Weird Shake on the Olds

[wilpetty]

Bought a 1990 oldsmobile. I just put on new tires to try and fix this shake. It seems to only happen on the last gear on the highway. The front end shakes really bad. Not a side to side wobble, but more of an up and down vibration. Tires did not help. If i keep it in Drive instead of overdrive it does not happen. Suggestions? Also when this happens I can let off the gas or give it more and when it downshifts, the ride is smooth again. What could this be?

 

[FAB454]

sounds like the torque convertor lock up. If memory serves there should be a 2 wire plug radiator side on the trans if you unplug it the problem goes away(with a slight loss of MPG)

 

[wilpetty]

I will love you if this works! What side is the plug? Front back driver or passenger? I dont know what radiator side means

 

[wilpetty]

Answer given did the trick! I believe the plug is called the tcc plug. It is on the driver side under the hood. It had 4 wires in it 2 of which were the purple and grey as stated above. It did trip the service engine light, but resetting the computer should fix that. Drives great on the highway and I still have overdrive I believe. I cruise at 2000 RPM's going 70 so if gas mileage is suffering, it is not by much!

 

[dyeager535]

I replaced the TCC in a 1988 Beretta a long while back. Pretty simple job actually. Would this be the clutch itself failing, or the solenoid?

 

[FAB454]

this test would be the answer
had to look it up: unplug connector, connect an ohms meter to pin A and D, run in 3rd or 4th gear, check value (should be 20-30 ohms).
book time is about 2 hrs to do the sol.

 

[dyeager535]

As I recall the solenoid replacement on the '88 Beretta was simply take the wheel off, take the vertical(?) pan off the trans, replace solenoid.

Maybe it's pretty similar in this case? If wilpetty is interested in fixing it at all. No idea if lack of TCC will cause problems with heat like it does in the 700's.

 

[FAB454]

sounds about right.
most people never fixed them, we would diag the car and they were happy just doing the unplug.... might have something to do with the area I was working in when these cars were still on the road.

 

[wilpetty]

Looks like the part is under 30 bucks on most sites. To me it is worth fixing right. How much time would this take going super slow (usually me)

 

[FAB454]

Dangerous question to ansure. Had a friend that did maintenance on boilers for for one of the big3 , so I figured hes mechanically inclined. So, the coolant quick disconnect was leaking on top of the intake(454 suburban) tell him its an easy fix.... 3 days later I get a phone call, he cross threaded the disconnect and cracked the intake.
short storry long, book time being <2hrs depending on tools,experience, work space, destractability, blahblahblah....... between 1-4 hrs
Just replacing the solenoid is a slight shotgun approach, but probably the cheepest option other than just leaving it unplugged. If you do change it, don't forget trans fluid and a gasket.

 

[dyeager535]

As Fab gave you the way to test the solenoid, do that first. If it's the converter clutch or something other than the solenoid, it would be a big waste of time, and of $30. As he says, who knows what could go wrong even not from your own mistakes...previously stripped bolts barely holding tight right now, warped pan flange, etc. Things happen.