A quick search of a few keywords resulted in one of my old posts.....
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I have done this swap, however, I removed the tbi equipment at the same time. I dont think that will be an issue because the speed sensor is on the t-case. Be aware that you will have an extra plug left over, b/c the 700R4 has a lockup convertor and needs the plug for it. (no biggie, just zip tie
it to the frame)
Things you will need~
1. T-400 Tranny with a 208 output shaft.
2. 208 t-case with a 32 spline input. The input on your current 208 is 27 spline and will not work. However, you can buy a special output shaft from Advance Adapters, but its pricey and you still have to take the trannyapart to install it. My advice is to get a 400/208 combo already together.
3. The above suggestion will give you the correct adapter between the t-case and tranny. If not, you will need the adapter for a 400/208 case.
Two versions were used, the short and the tall foot. You will have a short one in your truck because of its year. These are plentiful and shouldnt be hard to find.
4. With the correct adapter the length of the tranny and t-case will be the exact, and I mean exact length of you current setup. The adapter makes up for the difference. You will not need to change any driveshafts at all. Your current crossmember should be fine also.
5. Your shifter should hook up with no problems. The indicator on the dash will not be look right b/c it will now only be 3 speeds. This is no big deal as long as you can feel what gear your going into.
6. You will need to install a kickdown cable. This is electric and easy to do. The throttle pedal already has the holes for it and the switch can be bought at GM. You'll need to wire it into an ignition switched power source. Then hook the switch to the terminal on the tranny. (NOTE)~~~you
can run without this hooked up and it will do NO damage to the tranny. You will just have to manually downshift at higher speeds.~~~~
7. You will need a converter for a turbo 400, as the one with your current tranny will not work. The flexplate on the engine should not be a problem.
8. You will need a dipstick and tube for a 400.
9. You will need a gasket for the adapter to tranny, and the adapter to t-case. You can use RTV on the adapter to t-case, but NEVER, EVER use it on the tranny side of the adapter. RTV is VERY BAD on auto trannies.
10. The original cooler lines will also work just fine. Just make sure you are running an external cooler in conjunction with the one in the radiator. HEAT is the #1 killer of auto trannies.
That is all I can think of for now. I hope it helps. I'm fairly sure
this covers it all, but its easy to miss some things..
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Hope this helps..
John
