912 5 speed

[effvee]

Hi, thank you very much. I need to just start

[effvee]

Originally Posted by effvee

Hi, thank you very much. I need to just start

There is also mention of the first gear being weak, is there a fix for the first gear weakness?

[Bruce.]

The issue with the 1st gear is it sits on the end of the gearbox shaft, not between the two main bearings. So if you try to use a 901 box for drag racing, the first gear, being only supported on one side will not last long.

This problem was fixed on the 915. I think they swapped the position of the 5th gear and 1st gear.

For normal road use, up to around 200ftlbs of torque, I don't see this as a big problem.

A bigger issue with some of the 901 boxes, was the diff support. On later 901 boxes, they simplified the parts inside the diff and with wear, parts of the diff can suddenly drop. (!). However, it is not difficult to prevent.
If you remove the bolt from the centre of ONE output flange (do not remove both at the same time!!!), it may be a straight forward bolt or it may have a small nipple on the end. A box which uses nipple bolts has the weak diff. The nipple supports part of the dif and wears away over time, so the bolts need checked regularly and replaced when required. The diff can also be back-dated to remove the weak parts (bits from a 914 box work perfectly).