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More Transmission Woes...


Rocketman

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Hi all,

 

Just recently I've posted about TCC lockup issues on my '95 GP SE 3100 w/ a 4T60-E. I clipped the PWM wire on the TCC terminal and I have lockup again, its been running beautifully and getting great highway MPG's now, I've hit 31mpg on a trip to Baltimore and back. I have recently done a partial fluid flush, and I dropped the pan & replaced the filter. (within the last 2,000 miles)

 

In the last few days I've started to notice a few issues:

-When coming to a stop, it feels like the transmission doesn't want to disconnect, it bogs the engine untill it releases. Only happens occasionally.

-When going up hills, it seems the transmission shifts to too high of a gear, be it 2nd or 3rd i'm not sure, but it definately feels like the TCC is locked. The engine becomes very bogged and a sudden jab of the throttle makes no effect on rpm (hence my belief in tcc lock) and it requires a substantial amount of throttle to get the transmission to do anything.

 

The latter being my major issue. I though I heard a bit of a grinding noise when going up a hill yesterday.

 

Could this be my transmission puking, or a torque converter issue? I wonder if its not disengaging when its supposed to? Looking for some help here. I have the capabilities to replace the transmission, I've located a 4T60e at a junkyard within driving distance, should I be picking this up?

 

Thanks in advance for your input -

Rocketman

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Start with the basics: check the fluid level and how old is the filter? I don't know how you pull codes from a 1995, but I know you can somehow.

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Do you have a transmission cooler installed?

 

Not going to say this is the end all solution, but it certain helps fix a whole ton of transmission problems for a lot of people.

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Start with the basics: check the fluid level and how old is the filter? I don't know how you pull codes from a 1995, but I know you can somehow.

 

Post states the filter is less than 2k miles old. Just replaced it. Fluid level is perfect.

 

I have a small aux cooler I have been meaning to get around to install, but its not in yet. Don't think this is a heat issue, it happens regardless if I've been driving for 50 miles or I'm up the road from my driveway.

 

Thanks for the quick replies -

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Do you have a transmission cooler installed?

 

Not going to say this is the end all solution, but it certain helps fix a whole ton of transmission problems for a lot of people.

In this situation the damage is done and a cooler will probably not do a thing. Not sure what his issue is but i doubt it is heat.

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Drove ~20 miles a day for the last two days, and it hasn't been acting up again. I had disconnected the battery for ~2hrs the other day to do a PCM reset...but it was still acting up after that. Now, its been acting normal. So freakin weird.

 

Anyone else have ideas? It got cooler, so perhaps it is a temp related issue...i'll have to keep an eye on it for patterns

 

-Rocketman

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Installed a smallish trans fluid cooler I pulled off an automatic capri parts car I had a few years ago. Its ~5x10ish, i think its all aluminum not sure. Used the cold weather bypass that came with it (simple h-pipe) installed it inline AFTER the factory trans cooler in the radiator. Was driving around today could not replicate the problem again.

 

We'll see if this helps. Transmission seems smoother & more responsive though, could just be me, but idk

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  • 5 months later...

Update:

 

Trans has been acting up intermittently for the last ~5 months. Would work fine for weeks, then start upshift/locking randomly. Trans has started to make a whining and then rumbling/grinding noise. When in gears 1-3 it sounds like marbles rollin around. I made a diagnostic connector w/ LED's on the shift solenoids, confirmed the issues were the transmissions's doing and not something the ECU was commanding.

 

Got fed up with it...so I went to Harry's and pulled a trans from a '94 GP SE, only 94,000 miles on the odometer, I'm in the middle of swapping it now. Hoping this one's in better shape.

 

I'll dissect the old trans when I get it down, see if I can find anything clearly wrong with it. I can see there is lots of metallics in the fluid though, did pan drop/filter + fluid only ~6k miles ago. Something's amiss.

 

-Rocketman

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Sounds like the torque converter just shit the bed.

 

Also, for others, snipping the TCC PWM solenoid wire can restore TCC lockup, but it throws the trans into a slight limp mode and trans adapts are disabled, so shifting and TCC unlock can get quirky. Not to mention with the TCC being forced to run max, it puts more strain on the torque converter clutch and can destroy it along with other internal hard parts when TCC does lockup.

 

At least in OBD2 cars where the PCM can be tuned/reflashed, the PWM solenoid code that pops up after cutting the wire can be disabled to keep the trans outta limp mode, keep the TCC lockup from locking full on/harsh, and trans adapts stay enabled so shifting doesnt get hellish.

 

I have my OBD2 swapped 95 CS 3100 with the PWM solenoid snipped. At first it set a hard code, then shifting got quirky, and lockup was wayyyyy too harsh. After disabling the code, everything was all good.

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One thing I noticed with my diagnostic connector, is that the PCM would NEVER touch the TCC lockup unless it was 4th gear, over 44/45mph, and light throttle.

After clipping the PWM wire, TCC lockup was a little abrupt but I don't mind that, shifting was unaffected. No codes were thrown to my knowledge.

 

I had though about replacing just the torque converter, but it really seems like the previous owner of the car beat the piss out of it, and the trans was whining as well. Figured I'd be better off replacing everything.

 

When I get the new trans in, I will reconnect PWM and keep an eye on TCC lockup. I remember reading the PWM was mostly a '95 thing, I have a '94 4T60e, so we'll see what happens.

 

Replacing this thing is a bitch. Wish I had the resources to go 282/284 at this time.

 

-Rocketman

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Finished the swap, took it for a ride. Trans doesn't whine, shifts MUCH better and smoother than the old one. Problem though - it growls when approaching a shift point under partial throttle, can't really define the noise.

 

Fuck me, lol.

 

TCC lockup still seems intermittent, Ill need to put some more miles on it

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