I will explain how to make it happen, a swap-over from a 3 speed automatic transmission to a 4 speed automatic overdrive transmission with a lock-up torque converter. This maneuver will be performed on a truck that has four wheel drive. It is actually as easy or even easier in terms of parts. Obviously a 4 wheel drive (4×4) requires more labor since you are dealing with a transfer case now, which is heavy.
To start with, you will need the first four items listed in yesterdays post. The only differences would be:
1. You will need a 4×4 T-700R4 automatic overdrive transmission instead of a 2wd (two wheel drive) T-700R4 transmission.
2. If the upgraded 4×4 T-700R4 does not have the 4×4 adapter plate on it you will need to buy one. Hopefully (ask them to include it) the rebuilt upgraded 4×4 700R4 will have it attached already.
You will also need to count the amount of splines inside the input shaft of the transfer case (T.C.) so that you can order a T-700R4 with the same amount of teeth on the output shaft of the transmission.
From what I can remember about converting my truck and many others to an overdrive transmission, the rest of the parts are the same.
The beauty of a 4×4 change over is that all 4×4 700R4 transmissions are the same length. What that means is that you will not have to lengthen or shorten your drive-shafts. Four wheel drives have a front drive-shaft as well as a rear drive-shaft. Remember from my post yesterday, you may need to change the length of your drive-shaft in a 2wd transmission model..
It is more physical as I said before because of the transfer case which weighs roughly 60 to 80 pounds. A smart and strong helper would be nice. I highly recommend renting a floor transmission jack.
Don’t forget to flush your transmission cooler of all debris. You can buy a flushing agent in a pressurized can that has a screw on fitting that hooks right up to your cooler lines. Many transmission suppliers include the flushing agent with their products. They know what the score is! Again, cheat here and your rebuilt transmission may not even work.
As always, I recommend an add on external transmission cooler as insurance against excessive heat.
This swap-over one of the most effective upgrades one can do to their vehicle. My truck was converted about 8 years ago. It seemed like I bought a new truck at the time. Other then regular maintenance using synthetic automatic transmission fluid, I have never experienced a problem with it. This was a popular change over at my shop. About the only thing I ever heard from my customers was “I feel like I have a new vehicle now, except I did not have to spend $30,000”.
One thing we need to mention in our GotTransmissions Blog is safety. Be safe, use jack-stands that are placed well, have the correct tools and have a helper as I said earlier so no one gets trapped or unnecessarily injured. That was the first thing I talked about in my shop – safety. Be safe and good luck.
