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A604 Transaxle problems

21K views 16 replies 6 participants last post by  el conquistador 
#1 ·
I just installed a rebuilt Transmission Computer Module (made by a reknown rebuilder, with 4 moth warranty).
But the transmission still isn't working on my '93 Dodge Caravan.
Before I had it rebuilt, the car wouldn't shift from 2nd into 3rd gear but go into neutral and then stay in safe mode (2nd gear).
After I installed the rebuilt TCM, it reacts exactly the same way.
When I got back to this guy he said that the solenoid pack is most probably clogged and suggested I got a new one, but I already switched it ones, about a year ago and it behaved exactly the same way than it does now.

Any idea what else might be the problem? Perhaps a bad input or output speed sensor, or some of the contacts on the TCM connector?

Thanks in advance.
 
#2 ·
This is a classic example of throwing parts at a problem without proper diagnosis.

What you can do is remove the plug on the OD port as I explained in your earlier post. install a pressure gauge, even a cheapie oil pressure gauge will work. run the vehicle when it shifts to 3rd, you will see over 80psi pressure when the solenoid activates.

If it does, then your problem is an internal failure. Most commonly a broke overdrive hub.
 
#3 ·
Welcome to the forum, frankpistohl

Usually when a transmission starts to have shifting problems, it can often be caused by the solenoid pack, but not always. Rarely have we heard of a tranny problem stemming from the TCM, in any GEN van. We have heard of several caused by loose wires, or a bad ground wire to the solenoid pack. If you replaced the TCM, I would have to "guess" you cleaned the connector, or atleast inspected it, prior to re-connecting, the same with the solenoid pack connector(?).

These tranny's are "smart", so getting a "free scan" from a reputable place, and, your dealer (nothing wrong with several opinions). Just stay away from AAM**, unless you want to get your tranny back in a doggy bag ........

Providing us with your "miles" would help us in figuring a problem out, as well as "location". Winter "SALT" in your area, etc.
 
#4 ·
I wouldn't generalize that all **MCO stores are bad. Might as well say all Chrysler dealers will screw you over just because you hear or had one bad experience.

If the man just puts a pressure gage on the OD port (which applies in 3rd gear) and he has decent pressure, then he will know if the computer and solenoids are doing their job.
 
#6 ·
Milage, location,

to AzTraveller:
The mileage on my Caravan reads approx. 230.000 Km (142.915 miles). The vehicle is located in Caracas / Venezuela, so there is no snow or salt around.
Transmission (as far as I know) was completely rebuilt approx. 50.000 Km ago.
About a week ago I had the TCM rebuilt. And I know that it had two components blown 'cause I could see two burned spots on the gel-like back of the TCM.
The solenoid pack doesn't buzz at all, and the shifting between gears don't occurs smoothly but throws in with a noticeable ruck.

How would an A604 react if the input speed sensor and/or output speed sensor had gone bad?
 
#7 ·
A604 Scanner

To El Conquistador:

I just fixed a OBDII scanner. It had a damaged keyboard. Now I have to find someone with the hardware to connect it to the A604 transmission.

About putting a pressure gage on the OD port: What is the ecxact thread of the hole?

Any idea where the ground strap of the solenoid pack attached to?
 
#9 ·
An A604 tranny with a bad input or output sensor will go into Reverse, and second gear in Drive. (Limp mode). There will be no buzzing from the solenoid pack. There will be no gear shifting.

An OBDII reader is of no value when it comes to reading codes from a 93 van which is OBDI, plus it will not read any tranny codes. You need a scan tool at the dealer or tranny shop for this. Just my $0.02.

FredB
 
#10 ·
I use a Snap-on Solus. It works just as good as a dealer scanner.

For trouble shooting this transmission or basically anything mechanical or electrical, I would think it's important to have a shop manual that can answer your questions and have flow chart and schematics to solve the problems.

As I stated in another post about this exact problem the ports are as follows from Left to Right looking at the front of the trans. From the bellhousing toward the rear cover it's
1st port underdrive (1,2,3 gear)
2nd Overdrive (3, 4 gear)
3rd Rev input (reverse only)
4th TCC (torque converter control)
5th 2/4 (2,4 gear)
6th L/R (1, rev gear)
 
#12 ·
1994 was the first year for any car to have OBDII and that was only in the Neon's.

ATF+3 came out in 1990 and that's what your van came with but really fluid isn't that much of an issue as to your problem.

Be aware there are 2 diagnostic connectors on your van. Under the hood for Engine only, one under the dash by the fuse block (trans, abs, body, airbag)
 
#15 ·
Is it possible for the A604's solenoid package to clog (get stuck)?
And if so, is there a way to unclog it? For example with some kind of solvent or mechanically?
never ever seen that happen. Like I said from the start, you need to put a pressure gauge on the trans and see what is happening. if you have pressure then you can eliminate the sol pack. I've tried very hard to explain this. Try a google search on diagnosis of the trans. I found an excellent picture buy picture explaination on how to rebuild one.
 
#16 ·
OBDII came into effect in 1996 except for the Neons which had it in 1995. My 94 GC has OBDI as did my now departed 95 LHS.
I use Amsoil synthetic in my Chrysler trannys. Costs about $10 USD in Chicago plus our high sales tax. Don't know if it is available in "HUGOLAND" but if it is it will be high cost.
You could use Mobil1 synthetic tranny fluid. Don't use anything that says Dexron. Just my $0.02.

FredB
 
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