GU spline count

hi all. i have a 1998 GU 4500 auto with both front and back ARB air lockers and a GU late 2006 3.0l manual into which I want to transplant the diff centres. I know the ratios are 3.9 and 4.11 respectively, but I do not know if the axles in both models are the same? THanks heaps in advance. Steve

I wouldnt be putting a lower ratio into the 3l unless you gonna run really small tyres you will find the 3l will prob struggle with 3.9 ratios in it.

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Originally Posted by nissannewby

I wouldnt be putting a lower ratio into the 3l unless you gonna run really small tyres you will find the 3l will prob struggle with 3.9 ratios in it.

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Yes this is exactly what we would fear!!. So I looked at the maths with the gear ratio of 1st, 2nd and 3rd (pulling a 1.7 tonne van) of 4.11 diff (fitted) verses the 3.9 at 100 kph and the revs change is a 5% drop at 100 kph (any speed!) and is still within the torque band. Am I full of cr_p in my thinking? Please advise!

It prob wont be so much of the once you are going but the getting going that will be the issue. Not full of crap in your thinking its just initially getting that lump to move that the 3l will struggle with on the lower ratios.

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Originally Posted by gu2

Yes this is exactly what we would fear!!. So I looked at the maths with the gear ratio of 1st, 2nd and 3rd (pulling a 1.7 tonne van) of 4.11 diff (fitted) verses the 3.9 at 100 kph and the revs change is a 5% drop at 100 kph (any speed!) and is still within the torque band. Am I full of cr_p in my thinking? Please advise!

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5% increase in revs at 1:1 is roughly the 5% increase in drive torque, well worth the effort IMO.

But your title is about spline count??? Are they both H233's? if so all rear will be the same. If they are H260's then they can be either 34 or 37.