There is no need for any Mission Impossible theme music here because what we are about to tell you is completely possible and utterly doable. We are going to take all the fear out of the internal workings of an automatic transmission, and even go so far as to tell you that you can rebuild your GM TH700R4 at home without being ASE-certified in anything!
Automatic transmissions are not filled with magic voodoo no matter what the local transmission shop tells you. We called around to see what a rebuilt TH700R4 would cost us if we brought the unit down to the local shop and had them go through it. We were quoted prices from $550 to $1,500. Dang! Thats a lot of money. Being the inherent cheapskates that we are, were always on the lookout for ways to do things cheaper, and we are huge fans of doing things ourselves whenever possible.
But how can you rebuild an automatic transmission at home, you ask? We know what youre thinking, Nobody can do that! Well, were going to show you how. Actually, Paul Zank, of Technical Video is going to show you how. Paul has produced a series of videotapes designed to empower the average home mechanic with the ability to rebuild his own transmission. We called Paul at Technical Video and ordered up the 700R4 tape (about $40) to see if we could actually pull this off. We received a 90-minute, step-by-step tutorial video that shows Paul taking you through each step of the teardown, cleaning, inspection, and reassembly process of the transmission.
Most importantly, the video took away our fear of getting in over our heads on something we have never done. Along with the video we referenced our factory service manual, and a Haynes General Motors Automatic Transmission Overhaul manual to build our confidence before we started in on the project. We recommend you watch the video over and over until you can almost quote Paul Zank word for word.
When you have digested the video completely you should schedule a weekend to do the rebuild. Youll need a transmission overhaul kit that includes all new clutches, steels, seals, and gaskets like the 700R4 Pro-Super rebuild kit we got from TCI Automotive. If your core tranny is really worn, you may need some hard parts like gears, drums, or even a pump that could add big bucks to the cost! So try to get a good core. There are also a few specialty tools that we got from Technical Video that youll see in the photos.
Select a big enough work area that you can lay out all the parts in a logical order as you disassemble the transmission. We did it outside on a picnic table. If youre worried about screwing up, you can even make your own video of you disassembling the transmission to use as a reference for when you have to put the whole thing back together.
Take your time, but dont walk away from the project until you are done. When the whole thing is reassembled, reinstall it in the truck. If you followed all the instructions there wont be a need to cross your fingers. Itll work. Drive it for 200 miles, then change the fluid and filter. You can thank us later. We cant begin to show you the assembly process, but trust us when we say the Technical Video will hold your hand through the whole deal.