Hello! Im new to the board! I have a 90 aerostar and it dies when you put it into any gear. Ive read that you can test to see if its the solenoid if you unplug it. Can anyone tell me where the plug is? And will it be able to drive and shift with it unplugged(temporarily of course)?
The electrical connector for OD and torque converter lockup is located on the drivers side of the transmission in front of the shift linkage just above the oil pan flange. It is a small (3 wire) connector. To disconnect it carefully pry/ pull the connector straight up. Yes, you can drive the vehicle, you won't have OD or torque converter lockup. Check also for a shorted lead on one of the wires, that would activate the tc lockup. I've even seen a shorted lead inside the pan.
That tells you that it isn't because of an electrical problem in the TCC solenoid. The TC clutch may still be stuck on. Crud in the valve body or elsewhere in the transmission is preventing the TCC lockup hydraulics from losing pressure and disengaging.
Here's a test, just be careful and don't get anyone hurt. Pick up the drive wheels, start the engine, and drop it into gear. With the wheels off the ground, there won't be any resistance and the wheels should start to spin. If the engine can spin the wheels in the air, but stalls when you push the brakes or otherwise force the wheels to stop, then it is likely a problem with the TC clutch. You'll probably have to take at least the valve body out so you can clean it up real good.
I don't think it's terribly difficult, but you won't want to attempt it without a good manual. You can get ATSG manuals for $15-20, or go to the library and find a good transmission repair manual for the A4LD. For reference sake, the valve body is the part the the filter is bolted to.
That valve body with aluminum valves and housing is a bear to remove the gaskets. You must be extremely careful when removing stuck valves in order to not damage them. In my experience when valves stick in a valve body there is some other problem causing particles of trash in the oil. Check the whole transmission. When you pull the pan you will likely find more than the normal sludge in it.