What trans/tcase in cummins swap??

[td87]

Ok I am trying to gather everything I need for my cummins conversion into my 85 1 ton. I purchased motor mounts and crossmember from Tennessee diesel. Ive been keeping my eyes open for a 1st or 2nd gen still (want a full donor), I have a GM np205 and a GM np208 to chose from. I want an automatic transmission but don't know what my best bet would be, if anyone could help me out that would be awesome, thanks

 

[oopsman_09]

alot of people use the dodge auto. you could also use an allison but it gets a little expensive. you could go 4l80e but people say a fully built 4l80 will only hold a stock cummins. personally i like the allison and thats the route i would go... money permitting. cheapest way is nv4500.
check out www.4btswaps.com they will have more than enough information for you.

 

[TexasOutlaw87Cummins]

The cheapest way is the get rag !! The little
But more expensive is the nv4500 but autos just arnt any fun !! You build a truck build it how ya want it !! But swapping a manual in is cheaper easier ! An more fun to drive

 

[wildcatjason]

I've done the swap and a current cummins owner. If you go with an auto and use the 47rh/re. Make sure it is properly built. A stock transmission is a trash making machine behind this engine. They make max torque at about 1900 rpms and redline stock at 2500. If you do any power mods and most people start playing with the power screw and AFC star wheel because its just to easy to it will eat you clutch pack and torque converter alive. I personally believe a triple disc, extra clutch packs, and a shift kit for extra line pressure are minimum. I would research those trannys and put as many upgrades in it as you can afford. They are basically an old 727 with an overdrive bolted to it.

 

[MrMarty51]

Overdrive trans`LL get You above 90 Miles per with factory governering.

 

[wildcatjason]

Either way you'll want a 3200 Bosch spring. It's the highest you can go without valve springs and makes a heck of a difference.