whicch tranny?

[84gmcjimmy]

SM 465...free to $200

built 700R-4...$1500-$2000 (cdn $$)

The next to free SM465 will still outlast the built 700R-4, and you never have to worry about tranny temps. The super deep first gear makes crawling easy...

The 700R-4 does have overdrive which should gain you some mileage...but it also takes power to run it so it robs some of the mileage back. You'd probably gain 2 to 3 mpg over an SM465.

I'd run the 465/208 you have and keep searching for the NV4500.

Rene

Alright thanks Rene. I'll stick with the 465 then. When I get a chance to check out the junkyards, I will look for a nv4500. Don't know if they would have one though. I'll search tonight to find out dodge vs. chevy, years etc.

Have you found a nv4500? I remember a few months ago in a thread you said you were looking for one.

 

[kennyw]

With a 350, SM465, NP205, 4.10 gears and 33" tires you can get 12-15 MPG out of your truck and have the strongest combination. That is how I ran my truck for over a year without any problems. Hauling heavy loads I would still get 10-12 MPG. The cost of adding an overdrive tranny will far outweight the money you save on gas for the first couple years.

However, if you want a cheap easy way to get 18-20 mpg out of your truck go with a 6.2L diesel, SM465, NP205, 4.10 gears and 33" tires. That is what I am running now. The diesel motor paid for itself in 20K miles which took all of 2-3 months for me

 

[u2slow]

low IS worthless on the street even with my 3.42's/33's

I find 1st (low) quite useful for hill-starts, crawling in traffic, and jockeying around for parking, loading, etc.... thats my experience with 4.57, 4.10, and 3.73 gears. Rarely will I go for drive at not use 1st (low). The same trucks I would start in 3rd when on a slight downgrade.

There is lots of gearing in that bomb-proof SM465 package that can easily handle highway gears. I do recall one member here running 3.08's and 35" tires with an SM465 and was content with it.

I run 3.21 & 33's on my DD. It is a little awkward in city traffic (TH400 mind you), but has great highway legs. IMO, a small inconvenience to lower engine strain. It will be better when I get the SM465 in there.

but would result in runaway compression braking

Compression braking should be affected only by the same % margin as your cruise rpm improves. Direct trade-off I would think. Further reduction/compression-braking could be obtained with dual-cases... easily afforded from all the money you saved going with a cheap reliable trans, not buying NV4500 adapters, and not regearing your axles.