Can someone fill me in on all the steps im going to need to take from a to z to make this swap and have the 700r4 working properly? or send me a link to a thread with the steps i cant seem to find one... Thanks guys!
TH400 TO 700R4 Swap
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Thanks for the input. A 700R4 will handle what i presently have and at this point that is my only concern. Again, Thanks.
You'll need to get a new or shoten your existing driveshaft. Modify or get a new crossmember. Wire it to be able to lock up your convertor or go with a non-lock up style convertor. Get the geometry corrector and the bracket for the tv cable.
With a 700r4, which is similar in length to a TH350, wouldn't he have to move his crossmember forward and have a longer driveshaft? Basically what jrm81bu said, you may be able to use the existing crossmember, or just go with an aftermarket one from jegs which sell for a decent price. The driveshaft will definately need to be either shorter or longer.
Nothing wrong with a 700r4 at all, people just complain about the 1st to 2nd gear drop which you can make up for by climbing a little higher in the rpm's in first gear to make up for the gear drop. Can't be too bad if GM is still using the same transmission today, just became the 4l60 and 4l80's.
Nothing wrong with a 700r4 at all, people just complain about the 1st to 2nd gear drop which you can make up for by climbing a little higher in the rpm's in first gear to make up for the gear drop. Can't be too bad if GM is still using the same transmission today, just became the 4l60 and 4l80's.
Several companies sell lock-up kits, like this one from TCI.
I'm not sure what qualifies as a high hp engine, but 700R4's can be built to handle a lot of power. I'm not a fan of the 1-2 drop either, but I suppose you can compensate for it with rear gearing.
I'm not sure what qualifies as a high hp engine, but 700R4's can be built to handle a lot of power. I'm not a fan of the 1-2 drop either, but I suppose you can compensate for it with rear gearing.
patmckinneyracing said:
The 4L80 is geared differently and does not have the extreme drop that the 700R4 does. Having gone the 700R4 route in the past, I would much rather have a 4L80E. Although they do make aftermarket close-ratio gearing now for the 700. I'd be willing to give that a try too.
i have done this swap for a few freinds and a few customers
first thing is you need to get a dual pattern flywheel from GM the th400 has a larger bolt pattern than the 700r4
second is to get a afterarket X-member from jegs or summit or if you are handy cut the mounting tab off it and reweld it on when you have it bolted up
third is to get a floor shifter to accomodate the trans
4th after everything is in place measure for a new driveshaft if it needs to be longer you can have one made up with the ends you have from the old one just got to have it retubed. th400 and th700r4's dont have the same output yokes but the th 350 and 700r4's share the same spline and diameter and they are easy to find
hope this helped you
first thing is you need to get a dual pattern flywheel from GM the th400 has a larger bolt pattern than the 700r4
second is to get a afterarket X-member from jegs or summit or if you are handy cut the mounting tab off it and reweld it on when you have it bolted up
third is to get a floor shifter to accomodate the trans
4th after everything is in place measure for a new driveshaft if it needs to be longer you can have one made up with the ends you have from the old one just got to have it retubed. th400 and th700r4's dont have the same output yokes but the th 350 and 700r4's share the same spline and diameter and they are easy to find
hope this helped you
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