Aftermarket overdrive/gear splitter questions

[RLDSL]

THe formula, is take the gear ratio of each gear, and multiply it by the rear end ratio, then multiply that by the OD gear ratio and you get the final drive ratio for that gear.
You want to find an OD that ends up giving a parily even split between the gears for your rear end/ tranny combination. Granted, the ZF boxes and most pickup boxes are not ideally suited for splitting as the gears are not evenly spaced ( what I wouldnt give for a nice Clark 5 speed ) but you just have to find the closes match
I can't remember the formula for figuring the UD, I'll have to play with that for a while to remember
Some of teh boxes with give you a nice 3 way split on each gear and some like the one I got will just give you a serious deep reduction set, about 4 gears below 1st ( great for crawling into tight camp spots with the 5er without wearing the left knee out
Thene there are the 4 speed brownies that will give a good 3 way split plus a deep reduction.

 

[VanBoy]

Ah..... silly me.

I wouldn't mind putting one on that cab over Ford in my sig w/ the 3208. It has a 10 speed, but the rear axles were swapped out w/ an actual semi tandem by the last owner. Speedo is 10mph slower then actual speed. Prob. be a waist of time to put one on it... since it's a 200HP engine and a cab over...I guess only an air shift would work.

 

[RLDSL]

Ah..... silly me.

I wouldn't mind putting one on that cab over Ford in my sig w/ the 3208. It has a 10 speed, but the rear axles were swapped out w/ an actual semi tandem by the last owner. Speedo is 10mph slower then actual speed. Prob. be a waist of time to put one on it... since it's a 200HP engine and a cab over...I guess only an air shift would work.

I've driven twin sticks in a cabover before, It was an OLD freightshaker and it had a shiny 290 and a 4x4 tranny setup . The use heavy rods for the shift setup, and even without the air shift, I have seen ( that someone here pointed me to ) an electric solenoid shift setup made for 4wd transfer cases that could easily be adapted for use on one of these things for installation in a tight place..

 

[Lonesome7.3]

Wow, that is some very intersting reading.

 

[RLDSL]

Well, I finally got that Brownie all installed, just waiting on the batteries to recharge before I can take it out. Here;s the Pics

 

[Lonesome7.3]

That is very cool. I thought it would have been bigger. Maybe I should dtart looking for one of those.

 

[PackRat]

The DNE2(predecessor of the US Gear Dual Range) in my 85 dually was awesome. It puts a gear exactly where you need one, between 3rd & 4th, plus overdrive.

Nothing like stump pulling low end, with flat out top end. Having 'hurry up' in reverse is nice, too.

 

[Lonesome7.3]

I wonder how hard it would be to locate one of those.

 

[VanBoy]

I wonder how hard it would be to locate one of those.

There is actually one on Ebay right now.... but it fit's a C6 tranny out of an F250.

 

[Lonesome7.3]

Do you have the link? I have a C6 in another truck.

 

[RLDSL]

I finally got some clutch issues straightened out and got my truck on the road with the brownie box in it. So far, real happy with the results, good even splits and the OD drops my rpms about 500, so now I'm only turning about 1500 at 55mph in 5 over. This should make for a nice increase in fuel mileage. For normal empty driving, I can just leave it in OD and it's just like having a taller rear end, When loaded I have the splits and would start in Direct. That low range is seriously cool. It's going to be real nice for getting in and out of tight camp spots.

 

[Lonesome7.3]

That is very cool. I am planning a biuld for a 85 Ford when I get home. I think installing the same box will be perfect for that truck.

 

[VanBoy]

Do you have the link? I have a C6 in another truck.

Opps.... didn't realize it was closing the day I posted about it. Sorry. Only one bidder.... went for $700

 

[Lonesome7.3]

Is that a good price?

 

[VanBoy]

Is that a good price?

A local guy had one on CL for $500 a while back for a C6. On Ebay, some guys who 'clean' them up and such are asking over $1000..... and that is with NO drivelines at all. This US Gear had driveline parts....