Hey all, recently got my '82 SE running and driving again, but it's having a strange issue. At speeds above 50 mph or so, the torque converter isn't locking up (TH200c transmission, it does have a lockup) but instead is doing a strange surging action where the car will jolt forwards slightly at random intervals. Could this be a bad solenoid, low fluid, or a computer problem? The ECM is new, and I don't thing the lockup worked beforehand. Any ideas?

 

I would say solenoid. Someone I know had a similar problem & turned out to the solenoid.
I am sure others will have a response as I do not know if ecm affect the lockup.

 

Yep, the TCC is ECM controlled (provided it's not a "Canadian car")

 

Could I get pointers to where the solenoid itself is located on the transmission? Might try replacing that along with fixing the fluid leak it has

 

Inside it.

When you drop the pan you'll see some wires. Follow em. They'll start at a connector to the outside world, and end at ... a ... thing. Not hard. Just a car electrical system.

 

Easy test: unplug tcc wiring. Does it stop? Y -it's the TCC. N - it's something else.

Usually the bad TCC solenoids lock after warming up and stay locked until a cooldown cycle, or the transmission goes into a gear where TCC cannot lock (1st usually.)

The TH200-C is more work to replace the TCC solenoid than the 700R4 or 200-4R, unfortunately.

If it seems to be TCC, you'll want to figure out what is creating the command. Monitoring a wire with a bulb that lights up maybe.