The Ranger is for manual boxes and mounts between the gearbox and the bellhousing, so it will only have to handle engine torque (no multiplication). If you had an overdrive mounted after an auto trans, then presumably you would not need to use it as a splitter in the lower gears, only as an overdrive. In top gear with the converter locked you have a 1:1 ratio, so still no torque multiplication. I'm not 100% sure but I'd imagine that in 'direct' ratio it's a straight through drive. Besides, it only needs to be as strong as the transfer case.

 

My OD unit mounts on the tail shaft.

You are correct. A Ranger unit that mounts between the engine and manual transmission only has to handle engine torque.

Any OD or range splitter unit that mounts after the transmission must handle the multiplied torque from all gears. Some will handle straight thru 1:1 torque but may not handle it if in over/under drive operation. Check with the manufacturer. Most units are planetary gears that are brute strong.

 

I have a 74 F-250 4X4 and have gone through the same thought process as you have regarding the overdrive issue. I finally decided on going with the gear vendors unit for several reasons. 1. My T-18 granny gear is lower than the NV4500 which to me is a big issue given the offroading I do ( I like to crawwwwwwl). I also love my T-18 so why change? 2. The ranger units require remounting your tranny a bit further to the rear which also means your shifter is located more to the rear of the inside of the cab. Didn't like that idea 3. The gear vendors unit is stronger than any overdrive I have seen. It also has its own pressurized oil system which is more than I can say for other overdrive units. The downside is cost at $2,800.00 plus having to shorten the drive shaft $250.00. The only thing you have to do to install it is remove the tail shaft from the transfer case and mount the gear drive unit in its place. Very easy and clean install no cutting the floor boards no worrying where to run the extra linkage, you just run a cable up to your existing floor shifter with a button that mounts on the side. Just like the semi's have for their two speed rear ends. Now, granted I gave the other options a long hard look before deciding on the gear vendor but from what I can see its the best approach if you want strength, ease of installation, and factory appearance. I never really liked the idea of two sticks anyway. Plus you can split the gears as well. Take a look at their website at www.gearvendors.com you'll like what you see.

 

Karljay, do you know if that Ford F450 NV4500 used the Dodge ratios, the GM ratios, or a different set of Ford ratios? Would be really cool to find a Ford model NV4500 with GM ratios .

It is interesting that Ford would offer both the ZF 5-speed and the NV4500 5-speed in the same truck...

 

Cost is also a big issue as this is just a [B]play[/B] truck. Thats what I keep telling my girlfriend anyway I guess For now I'm just gonna keep my eyes open for a good deal to come along as I don't really need an overdrive unit, I just want one because I can . Thanks for all the replys, I really enjoy hearing everyones input.
-David

 

The US Gear unit is available in a 30% reduction ratio. The manufacturer is running a sale to its retailers until the end of May 2008, so now would be a good time to purchase. You can use my site at Boston RPM or any of the retailers listed on the US gear website.