best transmission for cummins swap?

[jimmy139]

Hi, I have a 1983 K3500 dually with a blown head gasket in the 454. The truck has a SM465 in front of NP205.

I have 2 cummins donor engines but they both have auto's behind them. I am wondering what the best choices are for a manual transmission to go between the Cummins and the NP205.

I would like to leave the tcase where it is and work forward from there, if that's possible.

any suggestions?

[Irish_Alley]

in order to leave the tcase you have to have the same size trans. the sm465 wont hold up to the cummins for long think its the 10 spline input shaft . the only trans that will hold up to a cummins is the nv4500 and 4l80

[bake74]

     Either transmission Irish suggested is going to need an adapter to mount your 205 to.

[jimmy139]

The adapter to go from GM NV4500 to t-case is available, but I'm not sure about what bell housing would have to be used, or where to get one.

Also, my digging shows that both the diesel and gas versions of the GM NV4500 are the lighter duty models, and I don't see any adapters to go from the heavier duty Dodge NV4500 to the 8 bolt racetrack pattern on the NP205.

I'm guessing the 10 spline input shaft on the t-case could be changed, but still need adapter between transmission and t-case mounting flange.

I'm not planning on high performance mods for this project, but it's still a truck with a dumping deck that will do a lot of towing service.

[Irish_Alley]

the th400 has 32 splines the 4l80e is also 32 splines. you can use the th400/205 adapter but you have to clear out the transmission side to clear the o-ring seal on the 4l80e. its not much but best to have a shop do it if you dont think you can. i hanvt done much research on the nv4500 so cant help you but from looking at pictures and memory you can oblong a hole on the 241 adapter to work with the 205 but this is just something i think i read. dont know about the input splines on the t case for that deal