I just picked up a th400 and np205. Looking to swap out my 700r4/208 combo. Wanting to get some opinions pros and cons. How big of a job is this and what hurdles can I expect. Will my existing cross member and drivelines work etc. Any feedback is appreciated.
CK5
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turbo 400/205 swap
- Thread starter BPK5
- Start date
I'm pro 400/205 however your biggest changes will probably gas mileage (no o/d) and less low range (700 has lower 1st gear than 400 and 205 = 1.96 vs 208 = 2.61?).
The driveshaft lengths will almost certainly need to be adjusted.
Also take note if the 205 has a bolt on or slip yoke tailshaft. Both will most likely have a flange style front output with the same bolt pattern.
The driveshaft lengths will almost certainly need to be adjusted.
Also take note if the 205 has a bolt on or slip yoke tailshaft. Both will most likely have a flange style front output with the same bolt pattern.
fyi any off road fun use . . . . twin stick the 205 when its out of the truck .
I did mine and LOVE the twin stick function .
I also did it for 2 friends when we had there 205's out and both were no I don't need it . but once done and in they cant stop playing with and using the twin stick function .
don't forget the electric gas pedal switch under the dash and the orange wire for it to the th400 electric kick down .
and if you can get the id plate 2 little screws / 7mm ? on the inst cluster to make it go from prnOd321 to a prnd21 .
I did mine and LOVE the twin stick function .
I also did it for 2 friends when we had there 205's out and both were no I don't need it . but once done and in they cant stop playing with and using the twin stick function .
don't forget the electric gas pedal switch under the dash and the orange wire for it to the th400 electric kick down .
and if you can get the id plate 2 little screws / 7mm ? on the inst cluster to make it go from prnOd321 to a prnd21 .
I did the same swap several years ago and the crossmember bolted directly back in the same position, I didn't move anything. I had an 83 700R4/NP208 and switched to the figure 8 style TH400/NP205.
I had the fixed yoke 205 and needed new d shafts. You may be able to get the front one shortened if they are both CV flanges.
Obviously you need the shifter from the 205 and the shift boot.
And it was already said to get the shift indicator plate in the dash from a 3 speed auto truck.
You drop the 700R4 TV cable, don't need that anymore, but you do need a vacuum line for the modulator(full manifold vacuum) and also a kick down switch. You can bolt in a factory switch at the gas pedal or make one from a small switch on either the gas pedal or the carb. Or you can run without it, but it will not kickdown or increase pressure at high throttle.
What you gain is a bullet proof drivetrain, what you lose is OD and a lower low range in the Tcase. Although the 205 low range is actually good for me in the sand, it's not too low that I can't go fast.
Since you have it out, if they are not rebuilt, I would at least replace all the external seals, like the outputs, and the adaptor seal, and the torque converter seal while it is out. Also, even if you don't twin stick it yet, grind the shaft for it while its out like they mentioned, then it will be easier down the road if you want.
I had the fixed yoke 205 and needed new d shafts. You may be able to get the front one shortened if they are both CV flanges.
Obviously you need the shifter from the 205 and the shift boot.
And it was already said to get the shift indicator plate in the dash from a 3 speed auto truck.
You drop the 700R4 TV cable, don't need that anymore, but you do need a vacuum line for the modulator(full manifold vacuum) and also a kick down switch. You can bolt in a factory switch at the gas pedal or make one from a small switch on either the gas pedal or the carb. Or you can run without it, but it will not kickdown or increase pressure at high throttle.
What you gain is a bullet proof drivetrain, what you lose is OD and a lower low range in the Tcase. Although the 205 low range is actually good for me in the sand, it's not too low that I can't go fast.
Since you have it out, if they are not rebuilt, I would at least replace all the external seals, like the outputs, and the adaptor seal, and the torque converter seal while it is out. Also, even if you don't twin stick it yet, grind the shaft for it while its out like they mentioned, then it will be easier down the road if you want.
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454Sub
5/8 ton status
I dont run the kickdown switch myself, I just manually downshift it when its needed, but I also use a B@M ratchet shifter so it makes this process easier.
