Diff ratios will sort the highway revs out. 3.0 will have 4.3. Get some 3.9 or 4.1's.
Just grab an 02 box out of any variant and swap it out as the 5th had been sorted by then.
A few guys have marks od 5th and like it. A lot of coin though!

 

Yeah I already have 4.6 ratios as I run 35's but don't really wanna change the diff ratios. Is it true that the 4.8 boxes have a standard lower 5 th gear ratio than the zd30 boxes?

 

4.6 and 35's is pretty old school. Lol
Most guys with power will run 4.1's and 35's.

There is a stat sheet somewhere on here with the ratios on all boxes.

 

Patrolapart have them pretty cheap , not a bad option if you look at the cost of a rebuild

 

Cheers simcoe, how the hell do I find that stat sheet on here?

 

That's off the marks site I could find the ratio chart, but there is a good diff ratio tyre size calculator in the technical section

I found this in another thread

Y61 Transmission Ratio’s as follows:
3.0 and 4.2 manual gearbox ratios = 1st 4.262, 2nd 2.455, 3rd 1.488, 4th 1.000, 5th 0.850, rev 3.971.

4.8 manual gearbox ratios = 1st 4.085, 2nd 2.353, 3rd 1.426, 4th 1.000, 5th 0.881, rev 3.806.

3.0 auto gearbox ratios = 1st 2.784, 2nd 1.544, 3rd 1.000, 4th 0.694, rev 2.275.

4.8 auto gearbox ratios = 1st 3.540, 2nd 2.264, 3rd 1.471, 4th 1.000, 5th 0.834, rev 2.370.

Transfer case ratios = high 1:1, low 2.02:1.

 

There are 2 versions of the gu 42 box. The one above, is as fitted to turbo coil cabs both dx and St.
Leaf versions and the odd non turbo coil cab have lower ratio first to third with a .836 fifth.
Same ratios as qg boxes.
Tb45 have a 91 overdrive from memory.
You can use the gq 5the in a gu box, just need to machine a spacer to fit between 5th, the the gu spacer, and the bearing to set snap ring gap.
Or you can, as my box uses, mix and match qg and gu internals in the gu case.

 

I can't for the life of me find where I read this but the crd manual box im throwing in my 99 dual cab td42t has a shorter first.
I believe the factory TD turbs wagon has the tall first while Utes/na wagon had the short first.