96 diesel in a 67 GMC

[67_C-30]

Originally Posted by TP from Cntl PA

It isn't the transmissions fault.............The NV4500 is a great transmission, the problem is the ENGINE is too much for it. You don't hear the Ford or GM guys having problems because their diesels won't lug like a Cummins. Even the Allison has limitations when bolted behind a 6-BT, I seen more than a few guys have custom shafting made for their Allisons on the Cummins Conversion board because of the fear of a turned up 6BT shreading everything internally because of the small shaft OD and spline counts.

If I ever use a Cummins for another swap, I am going to go with an Eaton...........I didn't even use a 6BT for my conversion, and I tore the heck out of my driveline twice..............The extreme amounts of torque and very low RPM just tears everything up. It doesn't help that we drive mine like a Semi, we pull it down to where its torque peaks out, engine keeps going, driveline says "NO!" But that is the trait I love about a Cummins, you can't kill them..............

I was talking moreso about the Dodge Auto trannys, but I have friend that has a salvage yard and he has had lots of trouble with NV4500's in his 3500HD Dump truck and Rollback with 6.5L TD. If you beat on any of the big 3's Turbo Diesel trucks, drivetrain problems will result. Lugging the engine down to the torque peak like you are talking about asking for trouble. My uncle used to run a pulp wood business, and they ran a lot 478 and 432 cu in GMC V6 gassers in the trucks, and when they would get them in a bind and lug them, it would destroy big Clark trannys.