Don't overlook the computer on the firewall that is usually above the alternator. It will cause your trany to default into second gear and make you think something is wrong with your trany which in fact is the computer itself. The other thing that is quite common with these tranys is the solenoid packs which is accessable right in the front of the trany and they aren't hard to replace, but you have to handle it like surgery...I mean clean, clean, clean. Anyway, you will need a motor support to hold the motor while removing the trany. You will need to take the ball joints loose to get the axles out, but drain the trany fluid out first since when you pop out the axles the fluid will run out. The bolts from the bell housing will need to come out and the transmission mounts and of course the battery will need to be taken out of your way. The bolts on the convertor, and if you get another convertor make sure that you take the old one into a transmission shop to match up since they have different convertors that the splines are different and will strip the first time you start running and you have a big problem then. You will have some connectors to unplug, a tranmission jack will be helpful. Note that the way the old one comes out the replacement will go in, but make sure that the convertor seats in well, usually 2 clicks to get a good seat. If you are using a junk yard trany, put new seals in on the convertor as well as the axles. There are going to be some things that you will have to disconnect that will be obvious when you get under there, but another thing after you get the other trany in, leave the return line off from the radiator. You will need to flush the system. I like to take a clear hose and place it in a 5 gallon buck out by the driver's wheel where I can see it and put about 5 quarts of trany fluid in the transmission and start it up and run it through the gears and watch the fluid turn to it's red color in case there is junk in the radiator or convertor or trany this will flush it all out. It takes about 10 to12 quarts of fluid to refill the trany.Note that the vehicle will run like junk for a little bit after having the battery disconnected since the computer has to relearn so don't get nervous at the first start up. If you are going to replace the trany, don't forget to change the computer on the firewall since they are noted for going bad and I would recommend doing that first before even going any farther unless you are getting slipping going on and you are sure the trany is bad. Good luck.

Before you do anything - (experience talking here) - drain the pan and pull the pan off - look to see if any metal shaving are present. If so, you'll most likely need to have the tranny rebuilt or replaced. If none are present, then proceed to replace the inner seal behind the torque converter.

If this does not solve the problem, proceed with having the computer tested and replaced if needed.

Please, let me know if you need any further assistance.

carsandcomps,

Guru, Premium Expert @ Fixya.com