71 Trans swap for towing?

[jerryk]

Need information! I have a 1971 Custom 10 with leaf springs, turbo 400, 410 rear gears, air cond.,PS..I pull a 24.5, 5th wheel and would like to install a tranny that has over-drive for max fuel milage with out trailer...Has anyone swapped a later model trans out of a PU? If so, how big of a job is it? Any advice would be helpful, even keeping the stock 400...

[Longhorn Man]

Welcome to the forum from freezing ohio
About the only over drive set up I would recomend for a towing aplication is an add on unit like the one from HERE This unit will hold up to anything you can give it, and probably more, plus, you can tow in over drive and have no problems.
The only OEM unit I would recomend would probably end up costing more than the gear vendors, and isn't as strong. (4L80E)

[1972C10]

4l80e is alot like a 400 but computer controlled and has the overdrive pretty good transmissions if you dont try to big rig it in overdrive.

Might look into a NV 4500 granny 5 speed w O/D Thats what i wanted to upgrade my 400 in an 85 i have but i kinda settled on the 4L80E Idea .

They make a kit to controll it without a computer and i have a magazine somehwere where chevy high perfromance or super chevy put one in a 84 dually with a big block . they got some kinda kit plumbed into the valve body so it split the gears out like a 6 speed it was wierd but most of that high budget stuff in there is.

[jerryk]

Appreciate the info longhorn and C10, this will give me something to work with..appreciate the link!
Aren't these old classic 67-72 trucks great? I sold my Silverado and decided to pull the trailer with old faithful.
I'm starting a club here in rainy Oregon for 67-72 pickups..Wish us luck, may see you down the road sometime..If your ever in Oregon, let me know and I'll let you know some of the best places to see or stay!.

P.S. This week we have sunshine and 60 degree temps! Its Feb!