200-4r issues

[horners85regal]

im leaning towards the vacuum switch, as he said if he taps on the brake pedal it stops the jerking, that means the torque converter in unlocking when the power is cut at the brake pedal switch.

 

[DoubleV]

im leaning towards the vacuum switch, as he said if he taps on the brake pedal it stops the jerking, that means the torque converter in unlocking when the power is cut at the brake pedal switch.

A 1986 Monte Carlo SS doesn't have a lockup vacuum switch.

 

[horners85regal]

well that throwsout any help I thought I was giving in reference to a vacuum switch ! Sorry didnt realise the ecm was in the 86 I just looked it up, the purple wire at the brake switch can be cut to prevent the converter lock up on the power side or tan with black at transmission is the ground side of tcc lock up. Still it is unlocking when the brake is depressed so the solenoid isnt stuck in the transmission i wouldnt think

 

[jkey]

The most likely cause is that the TCC (converter clutch) solenoid is stuck which is a very common failure mode for these. Replacement is easy just requiring pan removal and then a couple of 10 mm bolts.

Is there a way to unplug it and see if it is stuck before replacing it? I imagine if its in the pan it wouldn't be worth the time to do that. Wasn't sure if there was an external connector somewhere outside the transmission for it.

Unplugging it electrically will not help when the solenoid fails in this manner. There is an internal check valve in the solenoid that normally bleeds a hydraulic signal off until it is commanded on electrically. What happens is that this valve sticks closed, a mechanical failure, that will exist whether it's plugged in or not. This causes the TCC to apply at all times as the transmission shifts to second gear and beyond. The internal hydraulic signal drops off on the 2-1 shift so that's why the car doesn't stall when stopped even with the solenoid stuck.

I may put a new solenoid in it just to see. It's only about 30$ and the filter hasn't been changed in a long time either. It'd be a good excuse i think

 

[jkey]

would putting in a cleaner additive like a Lubeguard product or something similar possibly free it from sticking?