Thread: TCC repair\freshening up...

Hey everyone, at the end of June I'm driving to 2600 miles in my car, and I want to try and make sure it'll make it there, get the best MPGs, etc. I've had the TCC PWM solenoid wire (Pin 78) disconnected from the PCM for awhile now, because I have the oscillating RPM problem going up hills and all that. I know this is a band-aid fix, and I want to fix it correctly before the trip. I've read it could be any number of 3 solenoids, or even the torque converter causing the problem, so I'm not sure where to start. The transmission has 230k+ on it, and it hasn't been rebuilt to my knowledge. Other than this problem, it shifts great, I've done a flush and the DIY shift kit to it.

I'm not sure if I want to put a new valve body in this transmission, since it potentially has 230k on it. I can pick up a transmission from pick n pull for $117, swap my diff onto it, and put it in, but that's a lot of work. Mainly because if I have to drop the subframe I'm putting an aluminum one back in, and I need to replace my oil pan since it's dented, so that'll happen since I've changing out the subframe (aluminum oil pan). THEN, also since I'm putting a new subframe in I'll want to rebuild my LCAs, since I'll need an alignment anyways. So, needless to say if I go the transmission replacement route it opens up to a LOT more work, lol. If I go this route, do the 4t65es have the same torque converters as the HDs? I seem to remember reading somewhere that they were different by 500 rpm.

What do you guys think? Should I just replace the TCC PWM solenoid since I unplugged it and the symptoms went away?

If you did an actual flush that could cause other major problems unless you ment just pan drop.

Sent from my Galaxy Tab 3 8.0

Not sure what Russ is even talking about, flushes don't cause problems, they merely allow underlying problems to be more visible.

Sub will be off either way. Control arms are easy when it's off. Doing a soleniod is a fairly quick, in and out (as long as the 4 pos torx bolts behave). And while it's all chained up.. it's a great time to do that pan.

If you need 2600 miles, I'd think you'd be happier with a lower mileage unit. However .. what do you really want to spend/do to it?

You cant just put a GT trans in your car, it has a different gear ratio.

Originally Posted by Slick2500

You cant just put a GT trans in your car, it has a different gear ratio.

Well crap. I think it was just the HD diff that was the difference. If that's the case, I'm stuck with the trans I have now then. I can replace the solenoids, but should I replace all of them? What else should I do while I'm in there? I have a few hundred to throw at it, but I can't go overboard with it. IF I could find someway to make the GT trans work, I could get the trans, subframe, and oil pan for $188+tax...

Just the pan drop when I bought the car and installed the shift kit while I was in there. All the shifts now are nice and firm, I just have the oscillating RPMs if I have that TCC PWM wire connected. The transmission temperature hasn't gotten above 172F since I installed the cooler, prior to that is would get as high as 200F.

Thought the flushes move stuff around and cause problems or is it the fact it like cleans and any metal bits holding stuff together aren't there anymore and hence you find problems? Either way, listen to bill imagine I never commented

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A flush removes all the clutch material suspended in the fluid. Which often is all that is masking a trans that should slip. It also puts in fresh fluid with detergents etc. Which.. often a trans will go unmaintained, so this detergent etc helps expose issues.

It's similar to going from years of dino oil to synthetic. All of a sudden the engine develops a million leaks. It's because the detergents etc break down the areas the sludge has clogged and poof.. leakage.

So if I choose the solenoid route, should I just change the TCC PWM solenoid? Anything else while I'm in there?

You would have to change the gear ratio in the PCM.

Sent from A Galaxy Far Far Away........

Originally Posted by Slick2500

You would have to change the gear ratio in the PCM.

Sent from A Galaxy Far Far Away........

I figured, so I think I'm going to replace the solenoids. Which solenoids do you guys think I should replace, the PCS and TCC PWM? What about a used valve body? Should I maybe try a valve body from a lower mileage 4T65E?

I've done quite a bit to the car since I disconnected the pin 78 from the PCM, mainly the new alternator. The old one was causing all kinds of crazy things, so maybe this was an early sign, who knows. Either way, it's getting fixed either this weekend or next weekend so I'm not disconnecting it again. I also made sure the TCC switch was adjusted correctly, just in case. Before I started I disconnected the battery and touched the (+) and (-) wires together for 20 seconds, as mentioned in this thread:
http://www.grandprixforums.net/threa...CC-Oscillation
I don't know if any of this stuff will fix the issue, but at least I can rule it out before I tear into the transmission and\or sink money into it. If this stuff doesn't fix it, I'll start with new solenoids and hope for the best.

...and that was a fail. Chugging is back now that I connected the TCC PWM again. I think this weekend I'll replace the TCC PWM and the PCS solenoids.

SO I tore it all down and replaced the TCC PWM solenoid today, it wasn't too bad at all. The symptoms are better, but they are still there. I'd say at least 70% better. I'm thinking I may need to reset the TAPS...is there anyway to do that without a TECH II?

Bump?

So I changed the title, because I'll be tearing into it again next weekend, to replace the PCS, 4th shaft, and possibly the clutches\steels. Should I replace the clutches while I'm in there? I'm also ordering the channel plate gaskets and a new set of thrust washers, just to be safe.

How many clutches are you aiming to do, I'm thinking just 4th? You'll only come across a couple of washers. If you have a chance.. trans goo would be nice to have on hand, or at least some vasoline. To hold the washers to the channel plate.

When you changed the TCC soleniod. Did you stick a finger in the hole to see if the valve felt like it was moving nice w/o slop?

Not with my finger, but the old solenoid came out in 2 pieces, and basically fell out of the bore once the clip was out. I had to push the new one in to get it to pop in, and in doing so I could feel the valve\spring push back. What all clutches should I replace? I don't want to go too overboard with it, this'l only be the second time I'm in one of these transmissions, and I don't want to rebuild it while it's in the car, lol. I figure the 4th clutches will be off since I'm replacing the shaft, so why not put new clutches in? Are there other clutches that are easy to replace nearby too all of this (without having to tear in too much farther)? I'm hopfully ordering parts today so I can knock this out over the 3 day weekend.

Nothing else is really easy. You'd fight the heck out of any other things. That's why I was asking, once you go past the 4th hub..it becomes tough with it in the car.

One more trick.. some M6 x 1.00 bolts.. long like 85mm without heads are great to hold the gaskets on and help line stuff up when going back together. It's actually used as a tool in the manuals.