Tranny & T-case questions

[Brutus84]

Hey quick question i have an 87 K-5 with a 6 inch suspension lift and 35's. I just got it but there is no reverse, i was told by the last owner to put a new tranny in obviously. Its a 700r4 with a NP-208 T-case backing it up. Im at the point now where im looking for a new tranny to put in. I have now heard from a bunch of people that the 700r4 is a weak tranny and to not put one back in, so with this said would a TH350 or a TH400 be better to swap in, and what tranny would mate up with my NP-208?

 

[dabomb6608]

The 700R4 is a weak tranny in stock form that is for sure. Its really up to you on what you put in it. Do you want the overdrive? You can put a built 700R4 in it and would probably be just as good off as having say a TH350/400 but still have that 4th gear...The gurus should chime in with more info and better detail.

 

[xCaliK5x]

I'm in the same boat as you. I have slight slipping in third under full throttle going up hill. They are weak stock. Everything I have read is either the 700r4 is garbage and will break if you look at it wrong, to the 700r4 when properly rebuilt with upgrades is perfectly strong. I have no clue on who to believe, so trial and error and I'm going to rebuild mine.

 

[Greg Ducato]

The 700R4 can be built to a very high level of durability and having that low 3.06 first gear is as nice as having the .70 overdrive if you street drive the truck. Even a stock unit can do a good job for you if it is properly adjusted and not abused. The 700 has larger planetary pinions than either the 400 or the 350, has higher operating pressure and a better pump and lube system, especially the 87 and newer units. For all out, extreme use, the 400 is the hands down strongest unit you can use, mostly due to it's superior center support system and big output shaft, and the fact it was designed before weight consideration was important and thus is built with some substantial cast iron components and lots of friction area.