View Single Post
Old 09-11-2016, 09:23 PM   #73 (permalink)
Experienced UAW Mechanic
Join Date: Sep 2014
Location: Bear Lake
Posts: 363
Thanks: 7
Thanked 73 Times in 63 Posts
Originally Posted by funkhoss View Post
I did consider what you are suggesting--not the transmission in the Duramax trucks, though, but rather the five speed transmission that came in 3/4 and 1 ton pickups in the 1990's (the NV4500). With an NV4500, I could theoretically have enough ratio spread for towing and economy, and leave the same rear end in the car all the time.

However, there are a few reasons that I ultimately didn't go that route:

-The NV4500 is a fairly expensive transmission, even used, and pretty much never shows up in U-Pull yards around here. It would have cost at least 10 times what I paid for the NV3500. It also weighs twice as much as the NV3500 and would have required more extensive floorboard and crossmember modifications to fit.
-The NV 4500, besides being heavier, also has more parasitic losses and much wider "gaps" between the gears than the NV3500--all of which would make it less efficient.
-And if I went with the NV4500, I'd be running a "light duty," high-geared rear end while towing--and as I discussed earlier, there are many reasons that isn't a good idea.

The Camaro T56 was offered in 3 versions, but with some mix and match you can combine the 2.97:1 first with the 0.50:1 sixth, you can combine the 3.36:1 first with the 0.62: sixth.
The ZF S6-650 had a 0.72:1 sixth in the Fords, but GM versions got 0.76:1, and aside from their size and weight, their internal hydraulic pump adds much drag on the engine. The price is even higher than the Camaro T56, so forget it.
  Reply With Quote