Contour Enthusiasts Group Archives Forums Modifications Transaxle Transmission trouble, after driving for 45 minutes

You never stated that you had a TC slip code. If it is TC slip that is the problem you need to install a new TC. Once they slip the friction material is gone and they will never lock again. The new VB will fix the problem that caused the TC to slip but the TC is now damaged and must be replaced.

jeff

Well, after replacing the original valve body with a rebuilt VB with all new Sonnax valves about 2 weeks ago, it happened again yesterday. I was driving for about an hour at about 65 MPH, I get into town at a stop light, and the car shifts hard again, this time it did not set off any CEL. And after it did this about 3 times, I pulled off the road, shut off the car, then restarted it and it shifted fine after that. So why would this work? Shutting the car off for about 10 seconds, then staring it again. Hard shift is gone.

Any ideas?

P.S.
I did not install a cooler when I had the rebuilt VB installed.

Thanks.

I'm having the same issues. But why are they overheating to begin with, since it did not do this new? Is it anything to do with anything close on the engine overheating, catalytic converter etc?

At this point in the game, I would replace the ECT sensor and see if that eliminates your hard shifting after driving awhile. ATX uses ECT input to control trans shifting conditions during diffferent tempature ranges.....If you are only getting hard shifting after driving awhile, I would try this first.

Did you do a power flush after you replaced the valve body? If not I would have this done also.

I would also begin to suspect solenoid pack if the above does not work.....

Oh, yes have you ever replaced the TSS? If it is original, I would first replace it before anything else.

Bob

It sounds like your TC was too far gone, from the slipping, and it has started slipping again. I know that "Mercman" has stated that any TC slipage will kill the friction material within the TC.

RedCoat999 - The overheating issue is a very well documented problem in the CD4E's valve body piston design. The bores wear out and will cause the piston to hang inside the bore. The most common to wear, like this, is the piston that controls the cooler flow. And by cutting off this flow, it doesn't take very long for the fluid to get boiling hot. Once this happens, not only does it cause harm to the clutches and the like - but it also increases the wear in the other bores of the valve body as well.

Why does this happen with only the CD4E? Well, that is a two part answer that splits both ways actually.

1) It is not just related with the CD4E. All automatics have a somewhat similar problem.

See, as the pistons move back and forth in the bores, it actually hollowes out two seperate sections within the bore. Most of the time, the bores with wear unevenly. Don't ask me why, they just do. And this will cause the side of the piston that is seated in the widest opening to fall. This in turn will cause the piston to "stick", because the piston is no longer sitting in the bore perfectly straight.

If the bore wears evenly, the piston will actually float within the bore and this causes leakage. When this happens the piston could be slow to actuate, when the hydraulic pressure is applied to it, or not even move at all.

So, as you can see, this is a very common problem. And this is not just in transmissions. This same problem can be found in all types of air cylinders as well as magnetic actuators (which I used to see a lot of in my feild of copier/printer repair).

2) Well, whoever designed the pistons did not do a very good job. I'm not real sure what they were thinking. I'm betting it was one of those enginnering meets that went something like this...

Design team coordinator walks in the conference room, where awaiting him are three engineers with their ideas of the hydraulic circuit for the new CD4E transaxle...

"What do you have for me today?" He hears a quiet giggle from his co-workers.

"Yeah! Check this out! Wait until the mechanics get a load of this." This comment was followed by a slightly louder giggle from the engineers.

With an amused look on his face, the team coordinator says, "They will never know what hit'em!" Laughing out loud he excliams, "Send it over to production boys!".

Or something like that anyway.

Well, I cracked open the book. I think a key item is that after this problem occurs you shut off the car, wait 10 seconds and then everything is running fine again. If you had TC problem it generally would be more consistent in my opinion.

So the problem as I can tell is hard shifting that begins after driving awhile, shut off car, wait 10 secs and everything is fine for awhile........so.....


TSS - Provides converter turbine shaft speed info for torque converter clutch control strategy. Also used in determining static electronic pressure control EPC pressure setting during shifts.

Symptoms: no tc engagements or harsh shifts.

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TP Throttle Position Sensor - if a malfunction occurs in the TP sensor circuit, the PCM will recognize that the TP sensor signal is out of spec. PCM will then operate the atx at high EPC pressure to prevent transaxle damage.

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ECT Sensor -- detects temp of engine coolant and suplies info to PCM. ECT sensor controls Torque converter clutch operation.

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Tot sensor - Transmission Oil Temperature sensor is located on solenoid valve body. the PCM reads this sensor to determine temp of transmission oil. Determines shift scheduling and control of line pressure for cold and hot temps operation. If defective complete pack assembly must be replaced.

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MLP Sensor can cause harsh engagements and firm shift feel if defective


In order of replacement or testing.....

1. TSS Sensor
2. ECT Sensor
3. TP Sensor
4. MLP Sensor
5. Solenoid pack

Bob

Well, my TSS is original. Replacing this sounds like a good idea, after searching and finding that many people have had to replace it. So is this easy to replace? and where is it located? Also how much is the part and can it be purchased at auto zone?

Thanks guys for all this great info. You guys have really helped me out.

Nick

And what book is it that you cracked open? Looks handy to have around.