[cadengineer]

Opened box but all bearings look very good any thing els it cud be ,loud scraping noise when driving but no noise when stop or clutch pressed in ,I've also changed clutch bearing as was bad. Any ideas please help.

Have you looked at the crown wheel, it's a shrink fit onto the differential and can spin and move to a position where it rubs on the inside of the casing, it will slip and then the two faces will seize back together but the crown wheel will have moved towards the casing.

I have just opened my gearbox to find just that, it's moved about 7mm, luckily it has not done too much damage to the case.

 

[cadengineer]

How wud it move as the whole thing spins anyway? And how wud u repair?

The crown wheel is normally bolted to the differential in most transverse gearbox applications, but in the midland gearbox it's an interference fit (heated up to expand, put in place and as it cools it shrinks) like the starter ring gear on the engines flywheel.

There is an issue on the midland gearbox with this fitment where it can spin on the differential.

The only correct repair is replacement crown wheel and diff casing as an assembly, or a SX box.

In my case I am buying a complete gear set with upgraded bearings and new seals and fitting into my existing gearbox casing.

However I have heard the track day guys have the crown wheel welded to the diff, but taking care not to get too much heat into the crown wheel as it will affect the hardness of the gear teeth (not my option)

 

[cadengineer]

Need ya help mate or am I wrong and it can spin ,my pretty sure the pins go though both.which wud lock them together .

The roll pins only stop the shaft from coming out for the internal diff gears (item 2 in the attached PDF)

The crown wheel only mounts on the outer edge of the diff carrier, you can see what has happened to my crown wheel in the attached image, the 2 items should be locked together as one unit to enable drive.

Hope this helps.