Transmission Choices

[TomC]

Jay Leno's 6V-92TA with HT740 was a relatively simple swap using existing parts.  What is talked about here is redesigning the whole transmission system of beveled gears, mounting a different transmission, and linkage.  If that's what you want to do as a project-great.  To me-the 6V-92TA and V730 sounds like the way to go.  Good Luck, TomC

[RJ]

Tom -

Jay Leno's 6V-92TA with HT740 was a relatively simple swap using existing parts. 

Very true, altho it was a challenge to stuff the V-block into a compartment designed for an inline.

However, the illustration was used as a metaphor - anything can be done w/ enough cash!


Steve -

To help you ponder why GM stuck w/ a simple 4-spd manual, think about the way 95% of the highway coach models were operated:

Reverse:  To back the vehicle out of a flat passenger loading slip at a depot.

First: To get the coach rolling, 90% of the time on flat ground.

Second:  Good to around 30 mph, roughly 5 mph over the speed limit in most downtown and residential neighborhoods.

Third:  Perfect for those suburban 4-lane roads where the speed limit is 40 - 45, while enroute to the highway out of town.

Fourth:  Finally on the highway, cruisin' along.

Remember too that these basic ratios were worked out before WWII, going back to the first V-drive highway bus, the Yellow Coach 719 and it's successor, the YC-743.  Virtually all highways back then were two-lane, very, very few freeways, and 60 mph was considered "fast."

Instead of Rube Goldberg, GM decided that a KISS philosophy was better.

Make sense??

FWIW & HTH. . .

[artvonne]

How much $$ do you have?

  More time and tools than money I guess.   

[Mex-Busnut]

This is an excellent thread.

In my humble opinion, the 13-speed Road Ranger manual tranny is tops!

[Barn Owl]

Personally- just replace the 6-71 and 4 spd with a 6V-92TA and V730 Allison-then you'd have a real hotrod!  Good Luck, TomC

Having driven 4106 buses with the 8v71 4sp, 8v71 V730 (my bus), and a 6V-92TA V730, Tom is right, that setup is awesome and is very easy and inexpensive to do compared to anything else, thanks to all of the transit parts out there. If I ever get to re-power that is what I would do. The problem I have with the 8v71 non-turbo is that it is a fuel sucking, black smoke belching, no-power dog at 12,000ft. Not to mention that with all of those benefits of a 6v92ta you don't take a fuel hit. There is a reason Jay Leno with the setup he did. One last thing, that unique turbo sound is great!