The 2.0 litre, SOHC engine is standard in most U. S. spec Neons. It is not available in the ACR Coupe or the R/T. It is available as a deduct option in the Sport Coupe. Due to a shortage of SOHC engines caused by the introduction of the Plymouth Breeze, many Neons which would have shipped with the SOHC were given a free 'upgrade' to the DOHC. Also see the Neon Models section for availability of this engine.
The SOHC engine was the first to be released. 1995 m/y SOHCs have a slightly more aggressive cam, and the air intake snorkel is located at the rear of the engine compartment, leading directly into the air box. During the 1996 m/y, the intake snorkel was made similar to the DOHC unit, with the intake at the front of the engine. This is less effective due to intake air being warmed as it passes directly over the motor. Also, to improve idle quality, the cam was detuned slightly. Both of these changes reduced power output a small amount.
The SOHC head has not changed significantly throughout the years. However, the block was made common with the DOHC in the '96 m/y when the PCV valve was relocated.
SOHC Engine Specifics HP Peak: 132 hp @ 6000 rpm Torque Peak: 129 ft/lb @ 5000 rpm Redline: 6500 rpm Rev Limiter: 6750 rpm Compression: 9.8 to 1 Bore x Stroke: 3.44 in x 3.27 in Recommended Gas: 87 octane
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The 2.0 litre, DOHC engine is standard in the ACR Coupe, Sport, and the R/T. It was standard, but often deleted for credit, in the '95/'96 m/y Sport Coupe. Due to a shortage of SOHC engines caused by the introduction of the Plymouth Breeze, many Neons which would have shipped with the SOHC were given a free 'upgrade' to the DOHC. Also see the Neon Models section for availability of this engine.
The DOHC engine, both head and block, has remained largely unchanged since its introduction, except for minor improvements to the wiring harness.
DOHC Engine Specifics HP Peak: 150 hp @ 6500 rpm Torque Peak: 133 ft/lb @ 5600 rpm Redline: 7000 rpm Rev Limiter: 7250 rpm Compression: 9.6 to 1 Bore x Stroke: 3.44 in x 3.27 in Recommended Gas: 92 octane
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The TLEV (Transitional Low Emissions Vehicle) 2.0 litre, SOHC engine is standard in California, Massachusetts (and other states with low-emissions laws) on automatic transmission vehicles. It has been detuned slightly to 129 hp, to improve emissions levels. The compression ratio is reduced to 9.3 to 1, rather than the standard 9.8 to 1.
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The export Neon uses the 2.0 litre, SOHC engine. Horsepower and torque are each down 1 point, to 131 hp and 128 ft/lbs. Other than that, the engine is almost entirely the same as the regular U.S. version. The 2.0 litre engine is available with either the automatic or manual transmissions. Curiously, the Chrysler UK brochure lists the automatic as a full second faster than the manual in the 0-60 mph run.
In addition to the 2.0, there is a 1.8 litre version of the same engine for countries where there is a tax advantage to being in the under-2-litre class. This engine is not available with the automatic transmission, but comes with the performance manual transmission from the ACR. (1.8 litre Neon information courtesy of Aaron Mihe and the Export Neon FAQ.)
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A: As with all things Neon, opinions vary widely. However, many feel that the SOHC is better for street use because its torque peak is lower in the rpm range, allowing the engine more time in its power band under normal driving conditions. The SOHC is also a better choice with the automatic transmission. The DOHC does have more power in the top end, above 6000 rpm, which makes it the main choice for racers and autocrossers. Torque is also a bit higher throughout the power band.2.5.2 Q: What are the different cam specifications for the SOHC model years?
Under competition use, though, the DOHC does require more careful maintenance to avoid problems with its more complicated valvetrain. The DOHC is somewhat prone to rocker failure, and does not quite have the same reputation for bulletproof racing reliability that the SOHC enjoys.
A: After the 1995 model year, the SOHC cam was modified to improve idle quality. This caused a small but noticeable drop in performance. The cam changes are as follows:2.5.3 Q: Why do the two engines have different octane recommendations?
1995: Intake valve lift - 7.8 mm, centerline - 108 degrees, overlap volume - 2987 mm3.
1996-9: Intake valve lift - 7.2 mm, centerline - 113 degrees, overlap volume - 2039 mm3.
Note that the normal '95 spec cam is now sold as a Mopar Performance part; it is also available over the regular parts counter. The MP catalog lists a gain of four horsepower when installed in '96 and newer SOHC cars. Unlike the hotter MP cams, this cam does not require premium octane gasoline.
A: SOHC and DOHC engines have different engine controller programming. The DOHC, due to its more aggressive tuning, is calibrated for 92 octane, while the SOHC is optimized for 87 octane.2.5.4 Q: What aftermarket hop-ups are available for each engine?
Both engine controllers have a knock sensor, and will retard the spark timing if detonation (or "pinging") is encountered due to running lower-octane fuel. However, the controller will not advance the spark beyond its original setting, so using fuel of higher octane rating than recommended above gives no performance advantage.
A: The Neon aftermarket changes on a weekly basis. Because more items are coming into production all the time, we recommend that interested folks check the current opinions to be found on the Neon message boards elsewhere on this site. Some Neon-specific manufacturers have appeared; Mopar Performance has begun shipping its new line of Neon parts, and the car is attracting attention from some companies previously interested in imports only. Opinions vary widely on the effectiveness of each modification, however:2.5.5 Q: What oil should I use? What about additives?"When it comes to modifying Neon engines for more power, in my opinion, I wouldn't waste any money on a throttle body, header, ignition system, or any of that typical aftermarket bolt-on stuff... the Chrysler engine guys are horsepower junkies just like the rest of us, and they did the best they could with what they were given."However, one bolt-on everybody agrees on is a cold air induction system. Also from the same article:
- Erich Heuschele, from an article in Grassroots Motorsports, July/August 1998"An intake kit [is] worth a few horsepower throughout the rpm band, and make[s] the engine much more consistent." -E. H.This edition of the FAQ includes a new section on Performance Modifications, which includes information on the common bolt-on modifications, as well as a suggested upgrade plan for both the SOHC and the DOHC engines.
A: The factory recommended oil for both engines is 5w-30, year round. See the Owner's Manual for oil change intervals. Now, some notes that don't come out of the book:2.5.6 Q: What oil filter should I use?
Many people prefer synthetic oils such as Mobil-1, Castrol SynTec, and others. Synthetic oils hold up better under high temperatures, and some people feel they offer longer intervals between changes. Synthetic oils are more expensive than regular oils, but much less expensive than engine repairs. Most people who use synthetics find that they keep internal parts cleaner, and help extend engine life. I personally use Mobil-1 5w-30, and change oil and filter at about 5000 miles. In my opinion, combination or semi-synthetic oils are a waste of money. As always, someone will disagree.
Some notes for racers and autocrossers:"The SOHC can be raced using the lighter weight oils, too. I prefer synthetic... Racers of DOHC cars should run heavier 15w or 20w-50 synthetic oil, change it often, and install the restrictor (p/n 4856291) in the make-up air tube that comes out of the driver's side of the valve cover."Additives have some devoted followers, but most people agree that they are ineffective at best, and harmful at worst. Products like Slick-50 and others often contain Teflon bits in suspension. This can clog small oil passages, and in general is a source of internal gunk. DuPont, who makes Teflon, specifically recommends AGAINST using it in engines. Modern motor oils, particularly synthetics, are carefully designed formulas. Adding other products can interfere with the performance of the original oil.
- Erich Heuschele, Grassroots Motorsports
A: The Neon originally shipped with a large filter (Mopar p/n?). This was changed to a smaller filter (Mopar p/n?) by a TSB applying to all Neons. Due to the filter's placement, the large filter is vulnerable to damage, since it hangs down below the frame crossmember. Some people prefer to use the larger filter because of its additional element capacity, but Chrysler thought it was important enough to issue a TSB about, so I use the smaller item.2.5.7 Q: What spark plugs should I use? What is the correct gap?
I also use genuine Mopar filters, since they include an anti-drainback valve to stop oil from collecting in the filter when the engine is off. Dealer pricing varies from reasonable to ridiculous, however, so shop around. Some other manufacturers and part numbers are listed below:
Smaller filter: Fram PH-3614, Mobil M1-102
Larger filter: Fram PH-16,
A: The correct spark plug gap is 0.035" for both engines. Note that the Haynes manual has an incorrect gap specified for the DOHC.2.5.8 Q: What is OBD II? What are 'error codes'?
Many opinions exist on which is the best plug; the most important factor seems to be the age of the plug rather than the manufacturer. Changing plugs every 10,000 to 20,000 miles will keep them fresh. Most people agree that Splitfires or other novelty plugs do not provide any additional power, and are often more expensive. Some additional manufacturers and part numbers:
Champion: RC9YC (OEM plug)
A: OBD stands for On Board Diagnostics, and is a federally mandated specification for new cars, largely aimed at reducing emissions. The car logs certain problems that occur, and activates the 'Check Engine' light (CEL) to alert the driver. A mechanic with the proper DRB Scan Tool can the review this log in some detail to assist in repairing the problem. The most direct benefit is that owners can access some of this information themselves. Certain codes will set off the CEL while driving; some do not. It is a good idea to check for hidden codes occaisionally.2.5.9 Q: What is the significance of the timing belt? Are the engines an 'interference' design?
To read any OBD codes, perform the following sequence.
1) Cycle the ignition key ON-OFF-ON-OFF-ON within 5 seconds.
2) Count the number of times the 'Check Engine' lamp on the instrument panel flashes on and off. The number of flashes represents the code. There is a slight pause between the flashes representing the first and second digits of the code. Longer pauses separate individual codes. For example, flash-flash-flash [pause] flash-flash represents the code 32.
To cycle the ignition key ON means to turn it only as far as it takes to get the dash lights to respond. It does not mean to crank the engine.
Code Description of Trouble Code
11 Timing belt skipped 1 tooth or more from initial learned value;
Intermittent loss of either camshaft or crankshaft position sensor;
No crank reference signal detected during engine cranking
12 Direct battery input to PCM was disconnected within the last 50 key-on cycles
13 No change in manifold absolute pressure (MAP) from start to run
14 Manifold absolute pressure (MAP) sensor voltage out of range
15 No vehicle speed sensor signal
17 Closed loop temp not reached or engine cold too long
21 02 sensor problem (oxygen sensor), upstream or downstream
22 Engine coolant temp sensor out of range
23 Intake air temp sensor out of range
24 Throttle position sensor (TPS) out of range, or disagrees with MAP
25 Idle air control motor circuits problem, target idle not reached (+/- 200), vacuum leak found
27 Injector control circuit problem
31 Evaporator purge flow monitor failure or evaporator solenoid circuit problem
32 Exhaust gas recirculating (EGR) system failure or solenoid circuit problem
33 A/C clutch relay circuit problem
34 Speed control solenoid circuits problem
35 Radiator fan control relay circuit problem
37 Torque converter clutch solenoid circuit or park/neutral switch failure
41 Generator field not switching properly
42 Fuel pump relay control circuit problem
Auto shutdown (ASD) relay control circuit problem
No ASD relay output voltage at PCM
Fuel level sending unit - volts out of range
Fuel level sending unit - no change over miles
43 Multiple/ single cylinder misfire
44 Battery temp sensor volts out of range
46 Charging system voltage too high
47 Charging system voltage too low
51 Fuel system lean
52 Fuel system rich
53 Internal controller failure
54 No cam signal at PCM
55 End of error messages (If you get this only, no errors were found)
62 PCM failure - SRI mile not stored
63 PCM failure - EEPROM write denied
64 Catalytic converter efficiency failure
65 Power steering switch failure
A: Yes. Both the SOHC and DOHC engines are an interference design, meaning that the valves if open will conflict with the piston in its highest position. This only happens if the timing belt fails, since the valves are normally closed when the piston is at top dead center and the cylinder is firing.2.5.10 Q: What does the rev limiter do? What does the speed limiter do?
The Neon has a 100,000 mile timing belt; however, it should be inspected periodically. Failure of the timing belt will lead to collisions between pistons and valves, causing extensive (and expensive) engine damage. Diagnostic code 11 indicates possible timing belt problems, and should be taken seriously. Have the car towed to your mechanic if encountering this problem.
The timing belt can be easily inspected by removing the plastic cover over the passenger side of the engine (driver's side for you UK and down under folks). Look for any frayed or worn areas. Turning the engine over with the coil wire removed will allow you to inspect the whole belt one section at a time.
A: The rev limiter interrupts fuel supply in order to bring the rpm below redline. Note that this works only while accelerating! The Neon's manual transmission is very strong, and can be forced into low gears at high speeds. The car's momentum will drive the engine past the redline, and the rev limiter will not help in this situation. Also, the fuel cutoff is relatively sudden, and can cause throttle-off oversteer if encountered while cornering near the limits of adhesion.2.5.11 Q: Is there any parts interchangeability between the SOHC and DOHC motors?
As listed in the table for each engine, the SOHC rev limiter steps in at 6750 rpm, while the DOHC is set to 7250 rpm. Note that the DOHC is also rev limited at 6750 when coupled to the automatic transmission.
The speed limiter operates in a similar manner, based on indicated speed rather than rpm. This is done to prevent consumers from exceeding the speed rating of the OEM tires. All Neons (except ACRs and R/Ts) are governed at 118 mph, the maximum speed allowed on a T-rated tire. '95 m/y ACRs have no speed limiter; newer ACRs and all R/Ts are governed at 130 mph. This is a moot point because the ACR tops out due to aerodynamic drag at about 130 mph anyway.
A: "Putting DOHC pistons in an SOHC engine has been done. The two engines have essentially the same block and crank except for the PCV system in the '95 SOHCs. DOHC pistons raise the compression a little less than half a point. The DOHC engine actually has slightly less compression than the SOHC because it has 54cc of combustion chamber volume. The SOHC has about 48cc. Thats why the DOHC uses slightly domed pistons, to get the compression almost all the way back up.2.5.12 Q: Will removing the air intake snorkle give more power?
If you are planning on putting a DOHC head on the SOHC block even after you change the pistons, you'd better plan on getting a DOHC donor motor for the project. Otherwise, it'll get real expensive quickly. You'll need the manifolds, throttle body, sensors, some timing belt drive components, and wiring harness to get it running. You'll also need a DOHC computer to get the right fuel and spark. SOHCs and DOHCs will run with the wrong computer, just not that well. The fuel and spark tables are totally different because the engines have different airflow characteristics."
- Erich Heuschele
A: The '96-up m/y snorkle, which passes right over the motor, significantly increases the charge temperature of the incoming air. Simply removing the snorkle and using the stock airbox has not been shown to give a measurable increase in performance. However, it does put the air intake in about the same position as the '95 m/y SOHC, which has slightly better performance than later SOHCs. It is also much noisier, which is why the snorkle design was changed in the first place.2.5.13 Q: What does replacing the motor mount do?
If you do remove the snorkle, or have a '95 SOHC, there is a simple modification that is good for about 1 hp. Just remove the soft black weatherstrip at the rear edge of the hood. This allows high-pressure air from the base of the cowl to get under the hood at the rear of the engine, right where the airbox sits. The downside is that this will increase the temperature of the air brought in through the fresh air vents. Also, an underhood coolant leak can cause sticky white steam to blow over the windshield, impairing visibility.
A: The stock motor mounts (p/n ATX - 4668182, MTX - 4668183) are fairly soft, in an effort to reduce noise and vibration. This allows a lot of engine movement, interfering with quick launches and fast shifting. It also leads to wheel hop, where the front tire(s) shake rapidly up and down during a racing launch. Extended wheel hop can damage engine and transmission mounting points, and other components.2.5.14 Q: What is a 'bobble strut'?
Replacing the front motor mount (FMM) in particular is an easy way to reduce this problem. Stiffer mounts are available via the aftermarket, as well as "Rexified" stock mounts, which have plastic inserts to firm up the OEM unit. It is even possible to use solid mounts. All of these will improve shifting and launch quality, reducing wheel hop. However, expect to feel increased vibration from the engine, particularly at idle.
A: Another item is the torque strut (or 'bobble strut'), which is in the rear of the engine and goes from motor to frame near the firewall. It dampens driveline windup; the stock unit looks a bit like the pneumatic struts that hold up a hatchback. This can be replaced with a solid bar, which will increase noise and vibration but provide better shifts and less wheel hop. At least one person has a solid strut setup that is not anchored at the frame end. This limits windup under acceleration, but does not transmit vibration at idle. The bobble strut is found only on cars with manual transmission.2.5.15 Q: What is the DOHC 'oil restrictor'?
A: Under hard use (over 6000 rpm), the DOHC engine generates enough vacuum to inhale oil through the crankase ventilation system. The oil restrictor is a small insert that goes in the return air line that comes out of the driver's side of the valve cover. The restrictor limits the amount of airflow and prevents oil from entering the air intake system. This piece (p/n 4856291) is available over the parts counter for about $4.00. This problem was described in TSB #09-07-95, which specifically mentions ACRs. However, any hard-driven DOHC should have this piece installed.2.5.16 Q: Is there a difference between the DOHC and SOHC engine controllers? What about ATX and MTX?
The symptom that indicates this problem is smoking through the exhaust, particularly following a long, high-RPM, right-hand turn.
A: The powertrain control module, or PCM, is unique to a given model year and engine type. Actually, from '96 up, the unit itself is interchangeable; however, the programming is engine- and year-specific. Each type carries a different part number, which refers to the correct software flashed into the EEPROM chip inside.2.5.17 Q: Where is the PCV valve on my '95 SOHC?
There is little advantage to be gained by swapping controllers between engine types, anyway. The Neon engine will run with the wrong controller, but not very well. The cam timing is quite different between the two engines, which means the fuel ratio table for one engine is not well suited to the other.
The ACR engine controller, contrary to some rumors, is not substantially different than the corresponding type/year from a regular Neon. The only change is adjustment/deletion of the speed limiter. The important things such as spark timing and fuel ratios are identical.
While there are some differences between the ATX and MTX controllers, none affect the power out put of either engine. Some of the programming changes are as follows:
The PCM on a car with the automatic transmission is programmed to operate the torque converter lockup solenoid. The auto PCM also monitors the park/neutral switch input, and as a result has some strategies for controlling the idle air control motor when shifting from park to drive or vise-versa. As noted elsewhere, DOHC engines are rev-limited lower than usual to protect the torque converter. (PCM info courtesy of Greg Smith.)
A: The '95 m/y SOHCs have a plastic PCV breather box mounted to the block under the intake manifold, which is very difficult to service. '96-99 m/y SOHCs integrate the PCV baffling into the valve cover, similar to the DOHC setup. The '95 valve cover has no fitting for PCV airflow, but the '96-99 cover has the PCV air "out" fitting. See the question about intake systems below.2.5.18 Q: How does the PCV relate to my cool new intake setup?
A: Many people, when installing the Iceman or other cold air induction setups, buy a small filter to put over the breather fitting on the valve cover. This is not a good idea, since under certain conditions the breather will splatter oil out through this filter.2.5.19 Q: Is the Neon's engine really a Mitsubishi product in disguise?
Most kits come with a small fitting that must be drilled and tapped into the intake tube. The PCV hose is then attached to this fitting, which allows the cranckase to breath filtered air. DOHC owners should also install the oil restrictor plug in this hose.
A: No! This is a persistent myth, particularly among DSM owners, founded on the history of cooperation between Chrysler and Mitsubishi. In fact, the naturally aspirated Eclipse 2.0 litre is based on the Neon engine, which was entirely developed by Chrysler. However, the head is reversed in the Eclipse installation, with the exhaust manifold facing front. The Mitsubishi turbo engines, on the other hand, were designed in Japan and do not have any common parts with the Chrysler product.
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The Neon automatic transmission is a three-speed, mechanically-controlled unit. Shifts are regulated by throttle position via a cable attached to the throttle body, while an internal governor sets the maximum upshift speed at 6500 rpm. It has a lockup torque converter for improved mileage, but no overdrive like the manual has. It is an older Chrysler design, and as such, is a reliable, durable transmission. The automatic transmission is not a good match for the DOHC engine, because its shift points occur too early to make full use of the DOHC's high-revving power. DOHCs are rev-limited at 6750 rpm when coupled with the automatic transmission, due to limitations of the torque converter. For people with no tachometer, the SOHC turns about 3500 rpm at 80 mph in top gear, while the DOHC turns about 3750 rpm at the same speed.
31TH Automatic Transmission Specifics SOHC DOHC Final Drive 2.98 3.19 First 2.69 2.69 Second 1.55 1.55 Third 1.00 1.00 Torque Rating: 170 ft/lbs (approx.) 170 ft/lbs (approx.) Used in: All ATX models All ATX Models
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The Neon manual transmission is a five-speed unit that comes in three varieties, as described in the table below. The standard transmission, used in SOHC cars, has a slightly taller final drive than the two performance manuals. The original performance manual is used in all ACRs and R/Ts, and 1995 DOHC cars. The second performance unit has the taller fifth gear from the standard transmission, in an effort to improve highway driveability and fuel economy. In comparison to the automatic, the original performance manual turns about 3500 rpm at 73 mph in top gear.
The clutch disc diameter is 215mm. The OEM clutch comes in two varieties: standard (with separate plates and a different back plate) and modular (package unit, same back plate as the ATX). The regular clutch was used in all '95 m/y MTX cars built in either plant. For '96 m/y and newer cars, the Belvidere plant switched to the self-contained modular clutch, while Toluca has continued using the standard clutch throught the model run.
Note that the Neon's manual transmission is a New Venture design, and is fundamentally common with the GM J-body line (Cavalier, Sunfire, etc.).
A-578 (NV-T350) Manual Transmission Specifics Manual Performance Manual A Performance Manual B Final Drive 3.55 3.94 3.94 First 3.54 3.54 3.54 Second 2.12 2.12 2.12 Third 1.36 1.36 1.36 Fourth 1.03 1.03 1.03 Fifth 0.72 0.81 0.72 Torque Rating: 136 ft/lb (trans) 136 ft/lb (trans) 136 ft/lb (trans) Torque Rating: 160 ft/lb (clutch) 160 ft/lb (clutch) 160 ft/lb (clutch) Used in: SOHC
All ACR, R/T
1996-99 DOHC (ex. ACR, R/T)
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A: "You *must* use type 7176 transmission fluid in all Chrysler-built automatic transmissions since the mid-70's. Dexron II and III are much more slippery than type 7176/ATF+3 and will cause shuddering during shifts. The latest version of the Mopar ATF is Mopar ATF+3 type 7176. It is more heat resistant than the prior ATF+2 formula.2.8.2 Q: How can I increase performance for my automatic transmission?
Yes, there are aftermarket equivalents for the Mopar ATF+ auto trans fluid. I got a memo a few months ago advising that the following fluids are among those known to meet Chrysler's MS7176D specs:
Citgo ATF type 7176
Esso (Canada) ATF+2 Type 7176
Kendall Type 7176 ATF
Quaker State 7176 ATF
Texaco Texamatic Fluid CS 7176M
Valvoline ATF for Chrysler Vehicles
I have recently become aware of two synthetic fluids that meet 7176 specs:
Amsoil ATF (don't know if it's Chrysler-specific or not), which has been tested against the ATF+2 type 7176 specs and probably meets ATF+3 specs also.
Red line ATF for Chrysler vehicles, which has been tested against the ATF+3 type 7176 specs. Note that Red Line offers a specific ATF for Chrysler vehicles -- their Dexron/Mercon is *not* appropriate!
There certainly could be others out there that meet the 7176 specs that I am not aware of..."
- Greg Smith
A: There are several methods of getting more acceleration from an automatic, but all have some downside:2.8.3 Q: What are the shift points for the automatic transmission?1) Install a high-stall torque converter, available from Howell Automotive and other sources. The standard torque convertor will stall the engine at about 2100 rpm if the gas pedal is applied while the car is held stopped with the brakes. This is known as "brake-torquing" or "power-standing", and may damage your transmission if done for *extended* periods (it is safe if held for a short time, 30 seconds or so). Brake-torquing is done to allow the engine to be at higher rpm at launch, and thus closer to the power band. A high-stall torque converter stalls the engine at about 3000 rpm, which makes for better launches. However, it does so by allowing extra slip in the torque converter, which may affect overall performance. This requires dropping the transmission.
2) Install a "shift kit", available from Mopar Performance and other sources. A shift kit increases the hydraulic pressure applied during shifting, which means more positive, faster shifts with less slip. However, shifts may become noticeably rough for normal driving. Also, the Mopar Performance kit interferes with lockup of the torque convertor at cruise. It can be modified to allow lockup, but there is currently not a source of detailed information on how to do so. This requires dropping the transmission.
3) Install transfer gears with a shorter (higher number) final drive ratio. Mopar Performance had a set (p/n P4349677) which gave 1.22 reduction, but this is no longer sold. Units may still be available in some places. Howell Automotive offers used sets from a different Chrysler vehicle that can be installed in the Neon, for a 1.23 reduction. Shorter final drive ratios give stronger acceleration, at the cost of highway driveability and fuel economy. For example, a SOHC automatic turns 3500 rpm at 80 mph. After the gear swap, it would turn 3500 x 1.23 = 4300 rpm at 80 mph. This work can be performed through an access panel in the left front wheel well, and does not require dropping the transmission. Note that the SOHC and DOHC have the same transfer gears, even though their final drives are different. SOHC owners can't get a quick boost by switching to the DOHC transfer gears.
A: The automatic transmission will shift at different points depending on throttle position and engine speed. Under low throttle, the unit will upshift at very low rpm. Opening the throttle calls for a downshift and raises the upshift point rpm via a cable attached to the throttle body. However, at wide open throttle (WOT), an internal governor forces an upshift just below the engine's redline, or about 6500 rpm. Holding the ATX selector in a lower gear rather than 'D' will allow the engine to hit the rev limiter.2.8.4 Q: Why doesn't the Neon have a four speed automatic?
A: Chrysler tested the Neon with a four speed unit from the JA series (Cirrus, Stratus, Breeze). However, overheating due to the tight engine compartment led to durability problems and the idea was dropped. Also, Chrysler's marketing team does not feel that buyers are willing to pay a premium of several hundred dollars for a four speed automatic. Rumor has been confirmed that a four speed ATX will debut in the 2001 m/y.2.8.5 Q: What is a modular clutch?
A: The modular clutch is a sealed, non-serviceable unit that combines pressure plates, springs, etc. into a single, replaceable module. This clutch is standard in Belvidere-built '96-'99 MTX Neons, and supersedes the traditional unit in older cars as well (an adapter kit is available, p/n 4856319). From Greg Smith:2.8.6 Q: What kind of fluid should I use in the manual transmission?"A modular clutch is a preassembled clutch pressure plate, clutch disc and flywheel. It bolts onto the same crankshaft-mounted driveplate that the automatic transmission Neons use. It cannot be disassembled for service -- instead, you just replace the modular clutch unit with a new one.Note that most aftermarket performance clutches will not work with the modular setup. These may require back-dating of the flywheel and backing plate to the '95 m/y style.
Chrysler uses the modular clutch in the Belvidere assembly plant to commonize assembly processes. They can install an automatic transmission-style driveplate on all the engines, and they don't have to worry about aligning the clutch disc inside the pressure plate. The assembly is self-aligning."
- Greg Smith
A: "Just make sure you use the A578-specific semi-synthetic fluid (p/n 4773167) that's available at the dealer. It is specifically matched to the synchronizer material for good shifting, and has special friction modifiers to last a lifetime... You're on your own if you decide to use something else."2.8.7 Q: What is the duty cycle of transmission fluid for each unit?
- Erich Heuschele, from Grassroots Motorsports
A: In normal use, the automatic transmission fluid should never need to be replaced unless the transmission is serviced. Fluid level should be checked periodically and topped off with the correct type. Under severe conditions (taxi use - that severe) the transmission fluid and filter should be replaced every 15,000 miles. For most of us it seems that something in between, say every 50,000 miles, would be prudent.
The manual transmission fluid duty cycle is the life of the car. Even under racing conditions, there is no evidence that it needs to be replaced more frequently.
Either fluid should be replaced if water or other contaminants get into the unit.
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