Those who have had TCC problems.. (and speedo not working)

[AllGoNoShow]

I'm getting conflicted answers on whether this is a TCC issue or something else. What do you guys think?

 

I have a 90 GP with the 3.1 and 4-speed tranny. Sometimes (it is sporadic) when you get off the gas and brake after cruising at highway speed the engine will struggle (go down to under 500rpms-back up to 800) and eventually die. Very rarely when I'm cruising at just 30-40, it will actually stall when i get off the gas before i even brake. Suprisingly it doesn't do it when it is cold outside(didn't do it the whole winter) but if it gets to be 60 degrees+ outside, it will do it very often unless you shift it into nuetral and goose it a little bit before you start braking. What do you guys think? I just got this car from my father and i don't think he has done much to it the past 30K as far as upkeep.

 

Also, my speedo sporadically works, has been that way for 6 years. Again, it is tempature related. In winter it works all the time, it summer it will read sporadically and sometimes not read at all. The gauge cluster has been replaced...some say these speedos are mechanically driven (and i wouldn't know how it could give these symptoms if it was), other say there is a VSS...which one is it and how do i fix it?

 

So you guys have any ideas besides moving to Alaska and never having a problem in the cold weather? Thanks! I look forward to being a member here and contributing. I know carbed small block chevys and camaros and that is about it so im hoping you can help!

 

Nick

 

 

 

[Bossman429]

I'm getting conflicted answers on whether this is a TCC issue or something else. What do you guys think?

 

I have a 90 GP with the 3.1 and 4-speed tranny. Sometimes (it is sporadic) when you get off the gas and brake after cruising at highway speed the engine will struggle (go down to under 500rpms-back up to 800) and eventually die. Very rarely when I'm cruising at just 30-40, it will actually stall when i get off the gas before i even brake. Suprisingly it doesn't do it when it is cold outside(didn't do it the whole winter) but if it gets to be 60 degrees+ outside, it will do it very often unless you shift it into nuetral and goose it a little bit before you start braking. What do you guys think? I just got this car from my father and i don't think he has done much to it the past 30K as far as upkeep.

That sounds exactly like a failing TCC clutch solenoid. When you get off of the highway it is like you are driving a manual trans car, and didn't push the clutch in when coming to a stop. The TCC solenoid is no easy task on a 4T60, usually you have to drop the cradle a bit, or lift the motor. You also have to remove the drivers axle to take the pan off of the side.

Also, my speedo sporadically works, has been that way for 6 years. Again, it is tempature related. In winter it works all the time, it summer it will read sporadically and sometimes not read at all. The gauge cluster has been replaced...some say these speedos are mechanically driven (and i wouldn't know how it could give these symptoms if it was), other say there is a VSS...which one is it and how do i fix it?

That sounds like either a cluster or VSS problem. The way to diag it is to (unfortunately) pay someone with a scanner to plug it in and drive around. The scanner will read what the VSS output is to determine whether or not it's working. Working = bad cluster; Not working = bad VSS or wiring. If the cluster proves to be bad, you may try re-soldering the joints on the back, they tend to crack over time, and behave in the way you described

So you guys have any ideas besides moving to Alaska and never having a problem in the cold weather? Thanks! I look forward to being a member here and contributing. I know carbed small block chevys and camaros and that is about it so im hoping you can help!

carburators are my arch nemisis.

 

[Crazy K]

on the upper front of the transaxle, there is a plug that should be gray or black... that hooks into the internals of the trannsmission. unplug it, and the tcc selenoid will be disabled.

you can't miss it, it right next the dogbone engine mount... etc... etc...

 

 

as for the vss. buy a new one and install it, the vss is the the far right side of the case, right above where the passenger side drive axle comes out. see if that makes a difference.

 

I

[AllGoNoShow]

Does the VSS send a signal to tell the TCC solonoid when to engage/disengage? Cause i notice when i'm cruising around normally where it should lock up (low 40s or so) and the speedo starts acting up and wandering (going like back and forth between 35-50 even when im cruising steady at about 45) the TCC will engage/disengage and sometimes the tranny even seems like it gets confused and it will shift between 2nd and 3rd if i cruise at just the right speed like it doesn't know what gear to go in.

 

Where the heck is the VSS on this car? I noticed a connector and sensor when i did the plugs yesertday that stocks on the end of the tailshaft of the tranny where the passenger side CV shaft comes out...is that it?

 

I think the stalling part is fixed-i just did a tune-up and found all the spark plugs were 10+ years old (old "AC." label instead of the new "AC Delco") and had been gapped at .065 when the book says .045, but i still have this problem with the VSS.

[Crazy K]

Does the VSS send a signal to tell the TCC solonoid when to engage/disengage? Cause i notice when i'm cruising around normally where it should lock up (low 40s or so) and the speedo starts acting up and wandering (going like back and forth between 35-50 even when im cruising steady at about 45) the TCC will engage/disengage and sometimes the tranny even seems like it gets confused and it will shift between 2nd and 3rd if i cruise at just the right speed like it doesn't know what gear to go in.

well.. the vss should affect the tcc only, on a non-electronic car... but it might initiate a downshift when the tcc disengages... if it thinks it is going the right speed.......

 

may I suggest.... unplugging the vss and seeing if the car acts up on a test drive?

 

also have you taken the car for a test drive with the plug on the top front of the transmission for the tcc unplugged?

 

Where the heck is the VSS on this car? I noticed a connector and sensor when i did the plugs yesertday that stocks on the end of the tailshaft of the tranny where the passenger side CV shaft comes out...is that it?

on the very top of the case? That should be it.

 

 

 

I think the stalling part is fixed-i just did a tune-up and found all the spark plugs were 10+ years old (old "AC." label instead of the new "AC Delco") and had been gapped at .065 when the book says .045, but i still have this problem with the VSS.

that would definately be inportant to have fixed!

 

[Bossman429]

I didn't read CrazyK's post too welll, so I might repeat something, but:

 

The VSS does not send any signal to the TCC in any way really. The VSS simply send the vehicle speed to the ECM. The ECM then decides whether or not to engage the TCC based on many parameters including:

Vehicle speed greater than ~55 MPH

O2 sensors reading in closed loop

Coolant Temp up to a determined value

Basically the car has to be on the highway warmed up for the ECM to engage the TCC solenoid.

 

Try inplugging the TCC as CrazyK suggested.

[Pontiac6KSTEAWD]

I have to disagree with most of the posts. The engine dieing to me seems to make me think that the IAC or something simalar is the problem. The reason I say this is that with him driving at 30-40 MPH and the motor just dies, while driving? That is not the TCC. If he was coming to a stop, and under 15 mph, then I could understand. But 30-40?

 

I do agree that its probly the VSS is dead, or the magnetic pickup. One or the other...

[Bossman429]

I was under the understanding that it died after exitting the highway (55+ MPH) and coming to a stop.

 

[Pontiac6KSTEAWD]

Very rarely when I'm cruising at just 30-40, it will actually stall when i get off the gas before i even brake.

Nick

 

Looks like we might have both a intake issue and a TCC after re-reading it. Either that or he has a huge vacume leak.

[Crazy K]

vacuum leak?

 

does your cruise control work, and/or does the directional controls fo the climate control properly direct air from the vent and other ducts? That is one sign of a broken vacuum line..

 

sorry for my lack of clarity... it is described better above... the tcc is indirectly activated by the computer, based on set paramets... including the proper signal from the vss of the vehicle traveling at a preset speed