Trans swap from T400 to Overdrive

[Edahall]

Originally Posted by DetroitDan

see, I've been told not to even consider a 700, and I've been told that the built ones are fine. Obviously I wouldn't two in OD, I didn't use OD towing when I had my 97 4l80e. I would love a 5 speed manual, but it looks like it would be even harder to get all the parts together and make everything work. Plus I dont know which trucks I can swap out of, which ones to avoid, I don't know much at all about hydraulic slaves. But I'd sure like to drive one. I wouldn't consider an sm465, hate those clunky trannies. It's really just a 3 speed anyway, so no improvement over the th400.
So, no thoughts on how much an overdrive auto can help with fuel? I have looked at Gear Vendors, but they won't save you enough to pay for it for years.
I really don't drive on the highway, and the towing is only pulling the camper a handful of times a year. Which is why the 400 is still in there. I even considered swapping the 454 for a 6.2. But diesel is so much higher now it wouldn't be worth it.

Maybe I should start looking at nv4500s... Oh, one other thing, I've got an NP205 transfer case and auto locking hubs. I would love to keep this case in it if I can.

700R4's work great behind a 500-600 hp light weight car for track use. But I've never see one hold up well towing 10,000 lbs for long distances. If anyone knows where I can buy a 700R4 that is capable of heavy duty towing and not fall apart in less than 70k miles let me know, I'm very interested. I would like to put one behind a 6BT Cummins for another project build.

The NV4500 would probably be the cheapest solution for getting O/D. Find one out of a Chevy 4x4 so it'll fit to your 454.