I'm pretty sure the TCC solenoid is bad in my '88 LE. It appears to be locking up ok, but can't seem to make up it'* mind about disengagement until speed gets below 45 MPH. A whole lot of shaking going on between 45 & 55 MPH unless I back off the gas or pull it out of OD. I consider myself a fairly competent mechanic but most DIY info on replacing the TCC says "bring it to a mechanic". How hard is it to change out one of these and does anyone have a link to a procedure?
Thanks,
Jim

solenoids are inside the side pan. You basically have to lower the trans to be able to get it off. Several have had luck freeing up that solenoid by adding a can of SeaFoam'* Trans Tune.

Sounds more like a faulty ICM or coil to me.

I'll try the Sea Foam first. I don't think it'* an ignition problem as the car runs fine until it warms up - then the problem begins and the CEL light comes on. It'* throwing a code 39. So...no tips on changing out the TCC solenoid?
Thanks,
Jim

Changing the TCC is a piece of cake to do....

But getting at is is a whole other story. The transmission has to come out in order to have room to pull the side pan. After that pan is off, the TCC is held on by one bolt and a harness. One would also need to replace the side pan gasket and side pan gasket around the cv axle. These can be had at most transmission shops.

If you're actually pulling a code 39, it could just be a short in the wires somewhere. Check the harness at the transmission for corrosion. Otherwise, dump in some seafoam trans fix and hope for the best....

it is the tcc and nothing else.. i have a 88 sse with the same problem and i just have not bought the sea foam tranny tune yet.. but i will........ my tcc locks and shuts the car off when i hit speeds of 65mph or more....