So my my '94 IDIT w/ 5 speed and 4.10's is awful in my mostly road speed driving. Power is just fine but I hate being reved all the time and fuel economy is about nonexistent. I bought a dually axle and I'm going to do the swap from SRW to DRW as you can see I need. I have wanted to gear the new rear to 3.55's but of coarse I have to do the front to match. The DRW axle I'm getting already has 4.10's so it's a bolt in if I stayed geared the way I am, which just sucks without another gear at the top. I recently ran into a US Gear Dual Range or what I'm told is an old Doug Nash overdrive unit for sale and I got to thinking. I like the idea but it has it's complications as well. Almost since I got this pickup I've wanted to solve my gearing issues with a swap from ZF5-42/4.10 to a ZF6/3.55, but I want to hear some more opinions on the overdrive/splitter units out there. The regular common ones like the US gear and gear vendors as well as some that may be more uncommon or custom.
Which are the best the toughest?
Pros
Cons
A little US Gear info. After reading this I really like the sound of this unit.
http://www.dieselwarden.net/temp/usgear/US%20Gears%20overdrive%20manual.pdf
Some quick calculations: ZF5 OD .76 x 3.55 gears = 2.70 final drive ratio
.76 x 20% US gear od .80 x 4.10 = 2.49
This would actually give a little taller OD with the US gear 20% OD. 3.55 over 4.10 gives 13% increase
Which are the best the toughest?
Pros
Cons
A little US Gear info. After reading this I really like the sound of this unit.
http://www.dieselwarden.net/temp/usgear/US%20Gears%20overdrive%20manual.pdf
Some quick calculations: ZF5 OD .76 x 3.55 gears = 2.70 final drive ratio
.76 x 20% US gear od .80 x 4.10 = 2.49
This would actually give a little taller OD with the US gear 20% OD. 3.55 over 4.10 gives 13% increase
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