Transmission swap - OD

[crashz]

My dump truck will be down for the forseeable future, as I suspect that the injection pump has given up the ghost. While I won't enjoy it, it will give me time to start working on the back of the frame, dump body, hoist and a bunch of other things.

One of those is the transmission. The truck had an orginal th400 which was swapped out for a junkyard th400 after reverse blew out by the PO. The new 400 must be from a gas truck, as it revs like crazy to move, and shifts too late. In fact, I'm positve it came form a gas truck.

Now many years ago, my 83 had a 700R4. It was a plow truck for all its life with no real problems other than a trans guys convinced my father that the 700 was junk.

Fast forward to now. I was thinking rather than fix my current 400, what about buidling a good 700 for my truck? The truck will see extended highway use once its running reliably. OD will allow it to travel highway speeds and save a bit of fuel.

Now I know people have had these break behind a 305, but in reality the 6.2 diesel is nearly in the same power range. The big issue is weight. Can the little 700 handle a 10K lb rig with occasional towing? I've seen it work well in a 3/4 ton for plowing and towing, but a 1 ton dump?

A goal with this truck is to lighten it up a lot, so that the empty weight will be in the 5-6000 lb range. Thats a lot of fat to cut. The smaller, lighter 700 with a NP 208, single peice drive shafts, rear disk brakes and an aluminum body may get me there. This would let me haul two cubic yards roughly, without being overweight.

All opinions and comments welcome. Any addtional ideas of weight savings, transmission choices etc welcome as well.