Outer Limits 4x4 Board

Hey guys,
Trying to work out what I'm going to do with diff ratios on my latest toy, my Gq dual cab.
A few questions;
1. Are final drive ratios in a 4.5 GU auto box and the GQ TB42e auto the same?
2. What ratios are other guys running on TB42e with auto and 33s?

Wanting better offroadability but also wanting reasonable highway running. The truck won't be a daily driver but living in Dubbo have to cover some kms to get to weekend club trips. Haven't driven it for 12months on road but last drive from memory it was doing about 1700rpm at 100kms which from what I've read elsewhere doesn't seem right which is why I was asking about the gearbox ratios as I've fitted a GU box as the original box was fried when I bought it.
Any help would be great.
Thanks
Brad

You sound like you'd be better off changing your transfer ratios. Try Mark4wd.com

I thought the only real difference between the two boxs was that the GU box was built slightly stronger but ratios where the same.

turps wrote:I thought the only real difference between the two boxs was that the GU box was built slightly stronger but ratios where the same.

Gear ratios vary between engines and auto and a manual (even if it is the same engine and chasi). Transfer are the same for all (GU, GQ, TB, TD, etc.). R&P are interchangeble, but ratios vary depending on engine and trani type...

33" tyres, 4.6 diffs with Marks 5th gear overdrive (0.74) works out about the same as the standard 4.1 diffs
First 4 gears lower and a nice cruising gear in 5th.

4.6s and 33s would SUCK

4.1s would be pretty close. if you don't mind it reving a touch high u could go 4.3s

I had 4.11 r&p (manual trani) with 33" and the vehicle ran great on and off road, then I went up to 4.625 r&p and the vehicle ran even better off road, allthought it was a little fast still. Now, keep into account that I wanted better off roading, not caring how much on road I'd sacrifice. If you want to improve one without affecting the other, your only way to go is the transfer 4L.
A good excercise would be to calculate your crawl ratio for every shift at stock and start playing with the numbers to figure out where you want to be...

turbo gu wrote:4.6s and 33s would SUCK

4.1s would be pretty close. if you don't mind it reving a touch high u could go 4.3s

Not with this it doesnt http://www.marks4wd.com/products/gearma ... -gears.htm" onclick="window.open(this.href);return false;

that doesn't help 1st to 4th
I had 4.6s with 35s in a 4.2 diesel and it was the worst choice ever. went back to 4.3and it was perfect. the 46 didn't suit the torque band of the motor

turbo gu wrote:that doesn't help 1st to 4th
I had 4.6s with 35s in a 4.2 diesel and it was the worst choice ever. went back to 4.3and it was perfect. the 46 didn't suit the torque band of the motor

I tend agree with you there, however is all good for towing, and its mostly a touring setup.
And once in 5th with the turbo you never need to shift down very often.

Funny how things change from place to place. Up here a TD42 with stock ratios is seen as slow and lacking torque, so we tend to emmediately move up to 4.625; then again, this is a country that a 45 min drive is cinsidered as long

As far as the initial question, I would stay with standard r&p, strap on 35"s, and change transfer gears; allthought a turbo would not hurt

Clanky wrote:

turbo gu wrote:that doesn't help 1st to 4th
I had 4.6s with 35s in a 4.2 diesel and it was the worst choice ever. went back to 4.3and it was perfect. the 46 didn't suit the torque band of the motor

I tend agree with you there, however is all good for towing, and its mostly a touring setup.
And once in 5th with the turbo you never need to shift down very often.

It sucks towing aswell!!!
I towed my GU ute with my wagon with 4.6s then 4.3 and it was HEAPS better with 4.3s! Then 4.6s put it outside the torque curve at all the wrong times!!
On big hills with 4.6s it a constant change between 2nd and 3rd where as the 4.3s on the same hills holds 3rd!

4.6s only suit a car that never tows, doesnt care about highway touring rpm!! Or 1 with 37 inch tyres

turbo gu wrote: 4.6s only suit a car that never tows, doesnt care about highway touring rpm!! Or 1 with 37 inch tyres

And that would be me Although I got 38,5"s

turbo gu wrote:
On big hills with 4.6s it a constant change between 2nd and 3rd where as the 4.3s on the same hills holds 3rd!

Interesting, but I havent experienced this problem.
Also not disputing your findings, but curious as to how it cannot hold 3rd with a 4.6 if it can with a 4.3 (all things being equal)?
If your around the peak torque band at, say 2200rpm for example, the only difference should be road speed.

I also apologise to the OP'er for this temporary diversion thread if its not relevant to his cause