i'm now having the third nv4500 put in my truck. my question is this, what would be a better swap, the 5600 or a ZF 6spd out of a ford? Finances aside i'm just courious which would hold up better.

 

NV4500s are a good trans. are you replacing them with junkyard units or top quility rebuilds? I would ditch the ZF idea i dont think they are known for durabilty. NV5600s are expensive to rebuild also.

 

there rebuilds, i had a zf 6spd in the powerstroke i had and i beat on it pretty bad granted it did not make the power the cummins does.

 

the only thing with the ZF 6 speed, is keep clean oil in it.

As long as you follow that rule, they are reasonably bulletproof, but if the oil gets dirty, or starts to sludge up the oil pump, they tend to take out the center bearings, and they are a real bear to work on.

I have done a bunch of them, and all for that reason, otherwise they were fine.

I have seen a ZF that lost a rolled pin out of a shift fork, the guy looked at a cutaway view of the tranny, drilled a hole in the case where the fork should be, drove a new rolled pin into the fork/shaft, and plugged the hole in the case with a willow branch. that was 250,000 km ago, and that truck is still going, hauling him and his welding gear all over the place.

Bush monkey fix, in a bush monkey location.

 

http://www.sanco-bg.com/Conversion_NV5600.htm
read here. this guy made a website to solve the trans issue with our trucks and cost wise is nearly the same