TRNW PIC TIPS

  Early to late output carrier swap.

  Clutch plate usage chart.

  Inspect valve body boost bushing

  Underdrive piston wear

  EMCC Valve Body Identification

  2001 Differential Carrier Design

  Sonnax Input Hub Bushing Tool

  Chrysler converter cutaway

  Chipped Solenoid Switch Valve

  What to look out for when repairing solenoid pack

  Speed Sensor Pin Size Changes

  Accumulator Bore Concerns

  More Accumulator Bore Concerns

  Late Model Solenoid Pack Tips

REBUILDING TIPS

CLICK HERE to see a list of Special Tools for the A604 Transmission

This is an electronic transaxle. Always check for codes and perform proper diagnosis before tear down

If unit has major metal in it, replace the solenoid pack. Chrysler part #: 4504570

Be sure to update TCM to latest release

If pump has only 3 sealing rings, ('89 only) it should be updated to the 4 ring design. Pump, input hub, and valve body separator plate must be replaced. Chrysler upgrade kit part #: 4740075

If you only have 3 od clutch discs, upgrade to 4. All you need is a ud piston package. Chrysler part #:4886300AA

Thick od discs and plates are for the 3 disc design only. If you are going with 4 od discs, the ud, od, and rev discs and plates should all be the same thickness

The ud clutch clearance is adjusted with the reaction plate. A 4723682 plate and snap ring package is ideal

The ud and low/rev reaction plate painted snap rings go on top of the reaction plate, with the painted side down

The od and 2-4 clutch clearances are not adjustable. If they are stacked correctly the proper clearance should be obtained

The low/rev clutch clearance is adjusted with the reaction plate. A 4567898 plate is ideal. You can substitute 2-4 discs in place of low/rev discs to take up clearance. You will remove .010" with each disc substituted

Always upgrade the low/rev and 2-4 lip seals to the new d-ring design

Always replace the low/rev piston retainer with a 4431648. Don't overtorque the screws

The nut on the output gear is a 1 1/2''

Watch for a stripped spline on the od hub to front planetary carrier. Update package is availabe with larger diameter shaft and planet. Chrysler part # 4762712. The package consists of 3-pieces; the fr planet, the od hub, and the 2-4 hub

Replace all of the lip seals. Don't shortcut any piston seals

Do not use an impact to remove speed sensors.

Under the valve body, the accumulator pistons go in the case first then the springs. Opposite for the one that has a snap ring holding it into the case.

No gaskets are used on any of the 3 pans. Use a 1/8" bead of RTV. Don't overdo it. Be sure to clean the old RTV out of the bolt holes or case damage could result.

Always quick learn the TCM after overhaul or re-program.

On the 604 what I do is seperate the rings into 2 piles, drum and case. Look at the tapered springs and the one with the larger diameter goes to the case. They look close sometimes.
First drum retaining ring is the one with the eyelet that has a larger tab on one side. Install that with that larger tab to the left as you are looking at it with the gap up. Second retaining snap ring with the eyelets, I look at the wear patterns to see which side was up, wear on the inside of the ring goes up. I believe that is tapered side up.
In pile of snap rings for the drum, pull out the two flat rings. The one with the larger diameter goes in the lowest groove. Then your pressure plate and the tapered ring goes in over that. Tapered side up. Next pull out the two square shaped rings and the waved one goes in on the outside drum, then your OD to reverse pressure plate. Flate square ring goes in next. You end up with a flat snap ring that goes on top of the reverse pressure plate.
Case is easy. There is the small ring that obvisibly goes in the bottom to hold the spring in on Low & Reverse. Next ring is the thin flat ring. Lowest groove and the pressure plate rest on top of it. Tapered ring fits above the pressure plate with taper up. Finaly the large flat ring holds in the 2/4 piston assembly.
Jimmy Taylor

If you have a vb in stock with a 82 spacer plate, it will cure a reverse buzz.
Rick Anderson

This may sound over simplified, but anytime I have no communication, I unplug and plug back in again the computer harness to the computer, I do this about five times...Ninety five percent of the time, I get connected. Give it a shot... Jim, III

.I am beginning to not pay too much attention to codes as they seem to be set by some other condition then what the code suggests. So its back to basics for me...JimIII

Yes it is possible to get limp mode and have no codes. I found it to ussually be a bad fuse link that supplies battery (12volts) to pin 56 at the computer.

I have also here in Southern California fixed MANY MANY intermittant failsafe problems and codes with a speed sensor short harness and or a solenoid pack short harness. Short harness for speed sensors is part #04419478, don't have the solenoid harness # handy. Most all the problems I have seen are speed sensor harness related. Apparently the pig tails start to open after they get warm. Some time a code will be set. This will most of the time be code 39, gear ratio error. However have had a few that will not set codes. Do NOT use butt connectors for this harness, solder it in. I use a micro torch and sil-floss solder. A trip to your local Harbor Frieght will produce a holding setup with alligator clips and a magnifying glass for about $6.00

Yes, I've seen fail-saif without codes on several A604's. Most of the time, the TCM was brain dead.

While a bad TCM or loss of 12v to pin 56 can do this, so can a bad EATX relay.

It is not uncommon for a 604 transaxle to enter the failsafe mode and provide no codes. There have been several causes to this concern. One is a bad EATX relay. This one should give a code but sometimes it does not giving you this problem. Another is a loss of direct battery feed at pin 56. Could be a bad fuse or fusible wire. ATSG has a list showing if it is a fuse and which one it would be or if it is a fusible wire and what color it would be. Another cause is bad grounds or a bad computer....Rick Anderson

The main way the 604 establishes limp mode is it commands it! How does the computer command limp mode? It stops voltage going through the etax relay which in turns stops voltage from going to the solenoid pack's pin 4.

The TCM is the computer that controls the transaxle. It is located on the firewall (under the hood) in front of the passenger. It has a 60 pin connector. Do not torque the bolt on this connector. Just snug. Make sure the pins aren't spread or pushed in. Check to see that all the pins in the connector are snug with a drill bit (.059>.

Code 55 is the "secret" end of codes code that nobody seems to publish...Robb

Trying to work on a 604 with out scanning the computer is like banging your head aganst a brick wall, it will take a long time to knock the wall down.

604 codes:
Code 42 & 13--Have never seen 13 caused by anything but controller.
Code 42--Always resize harness connectors first- rarely code is due to truely bad solenoid body...Paul

On the A604 solenoid pack: It rarely fails. If it does, it sets a solenoid or pressure switch code.

Install the painted beveled snap ring: PAINTED SIDE DOWN!

Try a road test sequence like this...
1-2 up light throttle 5 times
1-2 up 1/2 throttle 5 times
1-2 up wot 5 times....
Same sequence on 2-3 ....
aAter all done then start doing forced downshifts from 2-1 then 3-2 then 3-1 (light throttle 2-3) 4-3 then 4-2.... The controller only resets the cvi indexes on kick down shifts! If the controller is ver. 7 or lower replace it... with a quick learn or reflashed unit.

Converter friction material break-up has historically been associated with imperfections in the front cover running surface. The T/C bolt length on all Chrysler applications is critical. Too long and you dent the running surface. (Very common failure)

I have not seen hardly any converter friction failures since I demanded a NEW set of bolts (the correct ones) be installed on every unit. It is my firmest belief the converter shops could eliminate 100% of the converters they get back with "dimples" on the friction surface. The complaint "your converter took a dump, friction came apart" would be a thing of the past. All this cured simply by supplying the correct bolts with every Chrysler/Mitsu converter...Yogi

The spark plug wires on some 3.3 caravans are routed right next to the TCM wiring harness causing RF interference, and a harsh 2-1 downshift. The fix is to wrap the harness with aluminum foil tape, but I just re-route the harnes away from the spark plug wires...Tod

Some problems that a new controller will fix:
1. limp in with no fault codes
2. Erroneous cvi values
3. And of course code 13

I fixed many gear ratio errors, but never with a new controller. My belief is that when people claim a controller fixed their gear ratio error, it just temporarily fixed an intermittant problem by making it tougher to set that code again. You see, the newer controllers will not set a code as easily as the older ones would. These vehicles will be back. Most gear ratio errors are caused by an internal failure, but wiring to the speed sensors, and the sensors themselves often fail....Tod

One tip that we do if we have a 604 come in with intermidate limp, or shift problems, is put it on the lift and jerk out the output sensor. If it has metal on it, we all know what has to be done. This saves a lot of time, and is quick. Of course if there is no metal, GOOD LUCK, recreating the problem...Dan

Dan..I love it!! That's exactly what I do to see if an A604 has geartrain damage! Pull the output sensor. An output sensor that has metal on it,always will have planetary failure. Good tip...Tod

Take a close look at the boost valve in the P-reg line up. It really wears out and causes the boost valve to stick in it's own bore.

Scanner Snapshots (movies) are often times not used, but they are a tremendious help.

To test the EATX relay, install it in the reverse light relay socket and with ignition on, and see if the reverse lights work.

To tell if the PR system is working or hung up (either physically or hydraulically) try pressure gauging the trans with the wire harness off. Remember on the 604's the PR system is not controlled by the solenoids. They control pressure to the clutches, therefore if the pressure is low in all circuits look between the filter and the solenoids, if it's low on one clutch look between that clutch and the solenoid....Jimmy

On some models, if you change the controller, you have to remove the wire from pin 49, or it will cause it to shift out of O/D when you hit the brake pedal...Tod

Beefing up the 2nd/4th Clutch pack by installing five clutches in the 2nd/4th pack. Been doing this tip for the last 3+ years or so and it works great:
Requires 4 low and reverse frictions
Requires 4 low and reverse steels
Requires 1 2nd/4th friction and 1 2nd/4th Steel
1. Install the 2nd/4th friction ( .086 )
2. Install low and reverse steel ( .067 )
3. In addition, alternate the low and reverse friction and steels.
4. The last steel installed will be the 2nd/4th steel (.101 )
From Showdown with Saddam, Turbo Tom....Kuwait

The EMCC program on the A604 is a one time program "supposedly to break in the torque converter when it is new....Some folks really love it because, the TC shudder is gone..Well, it should be, because this program will not let the TC lock up at all for the first 500 miles. Now it comes into operation and it starts apply and disengaging the TC clutch at varying pressures, "supposedly" to break it in....This also makes for some interesting driving up to 2000 miles, then the program ends for ever and then regular TC operation is in control....Jim, III

EMCC stands for Electronically Modulated Converter Clutch.. what it does is this...New chrysler product off the showroom floor, EMCC working, (actually not working) program will not let the torque converter lockup at all till 500 miles have elapsed. then it begins to supposedly begin breaking in the LU clutch by raising and lowering the pressures, changing the slip and other wierd things...it is supposed to stop doing this at 1500 to 2000 miles and be gone forever.. What happens is that for some unknown reason, the EMCC would become active again, but it may not necessarly follow the original instructions, it begins raising and lowering presssures on its own...It might stay activated for ten miles or a thousand. Generally it was of a short duration....What the customers gets is a pronounced shudder during EMCC operation, harsh upshifts and down shifts, and harsh torque converter clutch engagements. and by the time they get to you the vehicle is running fine, because the program has shut off, now everything is cool till it decides to turn on again... Basically the only clue you will have is the the fluid has deteriorated. It has been a big secret, but Chrysler scantool DRB II has the ability to eliminate the EMCC program by reflashing,,,not all computers can be reflashed....Chryslers secret bulletin on this is "Chrysler Bulletin 18-24-95"... Hope this is clear...JIM, III

Plug and unplug the connectors, going into the computer a few times...So far that has been the answer to scanner communication problems...Jim III

Everyone of these solenoid blocks that have 80k. miles or more will be junk because of those cast-in aluminum tabs under the two middle steel balls will be no good. Just dont even waste your time. I've taken everyone apart and they were shot except for a few that just out of factory warranty (3yr,36,000mi). Just pass the savings onto the customer. Those rebuild kits are like military intellegence.....torqueflit

When I put car into failsafe by disconnecting computer, car rolls free.That was a bright idea, putting the vehicle into failsafe to test what clutch is causing bind.