Chrysler A604 1990 Service Manual

You pull a Chrysler A604 1990 Service Manual off the shelf because you are tired of guessing which seal ring goes where. I have been inside these transaxles since they came out, and I can tell you that the factory documentation is the only thing that keeps you from stacking clutches in the wrong order. This is not a reprint or a generic guide. It is the original ATSG update handbook, 158 pages, released in 1990, and it covers every engineering change Chrysler made to the A604 from the day it launched through the 1990½ models. If you are rebuilding one of these or chasing a shift complaint, you need this on the bench next to your snap ring pliers.

Chrysler A604 1990 Service Manual: What the Factory Documentation Covers

Open the index and you see exactly what changed and when. The manual starts with the new 4-ring stator (reaction shaft support) introduced in April 1989. That single change affects oil feed to the underdrive clutch, overdrive clutch, and reverse clutch. If you install an old three-ring stator in a new transmission, you will burn up clutches inside a thousand miles. The manual shows you the part numbers and the machining differences on the input clutch hub bore. This is the kind of detail that keeps a transmission together.

Then it moves into the new lip seals, the parking guide bracket and parking pawl redesign, and the transaxle controller locations. There are five different controller designs, and this manual tells you which one goes with which production date. Page 26 covers the PRNODL and neutral safety switch changes. If you have a no-start condition or wrong gear indication, you will find the test procedures there.

New 4 Ring Stator and Reaction Shaft Support

This section is four pages of critical information. The old support has three sealing rings; the new one has four. The input shaft/clutch hub bore is machined differently to accept the longer support. If you mix them, the oil circuits cross-feed and you lose forward clutch apply pressure. I have seen that mistake cost a shop a whole day of labor. The manual lays out the parts interchangeability clearly. You also get the updated part numbers, so you can order the correct support the first time.

3 Clutch Pack Specifications You Need

The overdrive and reverse clutch assemblies changed in 1990½. The manual introduces a new 4-disc overdrive clutch assembly and a new overdrive/reverse piston. Stack height, clearance, and snap ring thickness all changed. Without the factory specs, you will guess at the clearance and end up with a soft shift or a burnt clutch. Page 42 gives you the assembly tips for the 2/4 and L/R clutch packs. That is the page you dog-ear before you start stacking steels and friction discs.

Fault Codes and Diagnostic Connector Location

Diagnosing electronic shift problems without fault codes is a waste of time. This manual dedicates pages 46 through 71 to fault code explanations. It covers the diagnostic connector location, what each code means, and the step-by-step test procedure. The connector moved with each controller design, and if you backprobe the wrong terminal, you can damage the controller. The manual shows you the correct cavity numbers and wire colors. For background on how automatic transmissions differ from Manual Transmission systems, that is separate knowledge, but this manual gives you the factory diagnostic flowcharts for the A604.

Torque Specs: Where to Find Them

Torque values are scattered through the manual because they are specific to each assembly. The bell housing bolt patterns changed (page 15), and the new pattern requires different torque. The valve body bolts, the pump bolts, the case bolts – all spec’d in foot-pounds. Aftermarket manuals often round these off. Chrysler’s factory documentation does not. You get the exact numbers, and you get the tightening sequence where it matters. If you skip the sequence, you warp the valve body and get cross-leaks. I do not care how many transmissions you have built – follow the sequence.

Why OEM Documentation Beats Aftermarket

Aftermarket companies copy from each other and miss updates. This manual was produced by the Automatic Transmission Service Group with illustrations and data directly from Chrysler. It is not a third-party interpretation. It includes the 1990½ updates that most aftermarket manuals never caught. If you are working on a Chrysler, Dodge, or Plymouth with the A604 (also called the 41TE in later years), this year-specific manual is the correct source. Related manuals in the same collection include Chrysler A604 Transmission ATSG Service Manual (a companion handbook) and Chrysler Stealth 1993 Service Manual – 1286 Pages Factory OEM which covers a different platform but shares some electronic diagnostic logic. For older Chrysler manuals, check Chrysler Stealth 1993 Service Manual – 434-Page OEM Factory Specs for comparison.

You will also find references to how the A604’s hydraulic circuits compare to Manual Transmission systems, but that is a different subject entirely. This manual stays focused on the transaxle.

Does this manual cover only the 1990 model year?

Yes. It covers the 1990 model year A604 transaxle, including the mid-year 1990½ updates.

How do I confirm I have the correct manual for my vehicle?

Check your vehicle’s production date. The manual specifically addresses changes from initial 1990 production through the 1990½ revisions. If your A604 was built after April 1989 (four-ring stator) or after the 1990½ changeover (new overdrive piston and input clutch hub), this manual details the exact parts and procedures. The VIN tag on the driver’s door jamb has the build date. Cross-reference with the controller design table on page 12 of the manual. If you have a later 41TE (1991+), you need a separate manual; this one is strictly for the 1990 A604.

You can rebuild an A604 blind once. After that, you learn the hard way that specs matter. Download the Factory Manual and keep a copy on your tablet or print the pages you need for the job. It is 158 pages of everything Chrysler changed and how to fix it right.