I'm suppose I'm deranged but.....

[Kspen90]

On one of my half drunken thinking sessions I came up with an idea that SHOULD work as far as I can work out with my limited knowledge. I'vs always wanted a 7th gear for cruising on the highway to lower the rpms but the zf-6 only has 6 gears of course and the tallest ring and pinion made for the rear is a 3.35 iirc and that still doesn't bring the numbers to where I'd like them. I also thought of having a custom ring and pinion cut but then of course the low end would got to hell in a hand basket which brought me to my idea, and as far as I can work out it should work but only for zf-6 equipped trucks. Mounting position and driveshaft modification aside, why couldn't you take a transfer case and turn it around backwards effectively making the outpu the input and the low range now the high range? I worked all the numbers and it lines out perfectly with the transfer case ratio to go from 6th in high range (which now would be low) to 4th in low range (which is now high). So what have I missed that keeps this from working? Will the transfer case not handle that kind of rpm? I have all the numbers written down at home if anybody is curious I can post them later.

 

[Kappa9012]

why not just install a gear splitter?

 

[rcr450mx]

What about finding a two speed rear axle?

 

[Kspen90]

why not just install a gear splitter?

Last time I checked there wasn't one made for the GM ZF-6 and gear vendors told one of the members on here to pretty much piss off.

What about finding a two speed rear axle?

Never heard of it.... Got a link?

 

[blk smoke lb7]

Um no

There is an add on overdrive i have heard of,theres some guy running around here in a hot rod dodge that has this and from what i hear its kind of like a 2 speed thing back by the rear end.i know nothing about this and or weather it works i do know a guy that rode in the truck and said its faster then hell and was beating any dmax with a caned tuner.i would really like to meet this guy on the street somewhere but it hasnt worked out.......Yet!

 

[Kspen90]

Um no

There is an add on overdrive i have heard of,theres some guy running around here in a hot rod dodge that has this and from what i hear its kind of like a 2 speed thing back by the rear end.i know nothing about this and or weather it works i do know a guy that rode in the truck and said its faster then hell and was beating any dmax with a caned tuner.i would really like to meet this guy on the street somewhere but it hasnt worked out.......Yet!

Hmmm..... Well upon consulting the google machine all the two speed rear axles I can find are an underdrive gear, not overdrive

 

[blk smoke lb7]

Hmmm..... Well upon consulting the google machine all the two speed rear axles I can find are an underdrive gear, not overdrive

That depends how you set it up,most guys want more pulling power not taller gears for better fuel milage,so they gear down you are looking to gear up.I will ask my buddy tomorrow what the name of this was.

 

[Kappa9012]

interesting, I new gear vendors thought their shit was gold, but I have never looked to see what they offered for larger trannies.

 

[mill1901]

A two speed rear axle uses a solenoid to engage a planetary gearset. I am not very familiar with them, but I know that a lot of the two speed rear axles were used on 60's and 70's trucks. I've driven an International and two Chevy trucks with the two speed rearend.

 

[rcr450mx]

I did a little more research and you can find two speed rear ends all the way up into the early 90's in chevy top kicks. The rear ends were produced by Eaton. The two speeds were popular around the 50's and 60's when trucks were under powered.

 

[Kspen90]

Im still wondering why the t-case won't spin backwards

 

[TeaBagger2006]

Man I missed your threads!!! Didnt even read any of it....now im gonna scroll back up and read it then make a smart ass reply

 

[TeaBagger2006]

Kspent.... why not just kick into neutral more often???

 

[whitetrash21]

:rofl:

 

[LWATSON]

Im still wondering why the t-case won't spin backwards

It should spin backwards, it does when your in reverse.

 

[Kspen90]

Kspent.... why not just kick into neutral more often???

Because kickin it into neutral doesn't help me cruise down the highway at 100mph with low rpms at 4 in the morning like I like to do on a regular basis

It should spin backwards, it does when your in reverse.

That's what I'm thinking But there's no way I've actually had an original, feasible, great idea!

 

[Kspen90]

And the numbers are as follows that I worked out with a calculator and the speed calculator here http://www.catherineandken.co.uk/sti/tyres.html

Transmission ratios:
1st-5.79
2nd-3.30
3rd-2.10
4th-1.31
5th-1.00
6th-.72

T-case ratios
High-1:1
Low-2.72:1

So top speed with my tires and 3.73 ring and pinion is 113 at 3200rpm but when the t case is turned around and shifted into low, which is now high, it effectively multiples the engine rpm by 2.72 which would put me shifting from low range in 6th gear at 113mph@3200rpm into 4th gear in high range at ~2100rpm and could be run up to 169mph@3200rpm given enough power, stability, downforce, and most importantly, enough balls!

 

[Chevy1925]

Your problem will be "how are you gunna attacht it" and i dont think the oil pump for the case works in reverse but i could be wrong.

 

[LWATSON]

That's what I'm thinking But there's no way I've actually had an original, feasible, great idea!

Usually really good ideas hit you when you least expect it.

 

[Kspen90]

Your problem will be "how are you gunna attacht it" and i dont think the oil pump for the case works in reverse but i could be wrong.

The attachment would be a bit difficult but its nothing that some custom fabricated bracketry and an assortment of custom made shafts wouldn't solve.