US Gear Dual Range

[kennyw]

My '79 K20 now has 4.10 gears, 285/75R16 tires and a SM465/NP205. Looks like I'm spinning 2713 RPM @ 65 mph. With the diesel engine now in I need to start lowering the highway RPM's. I have a fairly worn set of 36 x 12.5 x 16.5's that could bring it down closer to 2487 @ 65. Probably still going to need to add an OD unit at some point in the future but it looks like it would get me down to 1990 RPM @ 65 with the 36" tires (2296 RPM @ 75 mph).

I'd like to go with the US Gear Dual Range unit between the tranny and tcase to be able to split gears and just starting to gather info on them US Gear Dual Range unit
Any opinions on this unit? I'm picking up a 32 spline SM465/NP205 combo to rebuild and run with this unit... Going to take some time to save up my pennies and buy it though /forums/images/graemlins/thinking.gif

 

[joez]

Are you running a 6.2? If so, i would just run it for now. The motor will be fine turning 2700 rpm on the highway, fuel mileage wont be the greatest though, probobally get you between 15 and 18 mpg on average driving. No need to slap the 36's on, unless of course you want to. Me personally, i would just run it as it sits, and save up for either an NV4500 to swap in, or that overdrive unit you are looking at.

 

[kennyw]

I just put in a 6.2 but the main reason for getting it was the economy (and still have as much if not more power than the original 350). Since I've put 100K miles on my truck in 1.5 years of owning it I'm wanting to get up to 20mpg or better /forums/images/graemlins/thumb.gif