Carrera Transmission Rebuild Suggestions Please

[Peter Zimmermann]

Originally Posted by SteveWig

Slight hijack..
I have my '77 mag 915 apart right now and am trying to put my shopping list together. The obvious syncro's, sliders, and dog teeth will be replaced. The big unknown is the bearings - big $$ to replace them all. I've looked at them all very closely and they all look good and spin freely. I have no info on the history of the trans. but the general condition is good.
What is the conventional wisdom on bearing replacement?
($1500 + to replace) That is the money I was planning for the Wevo internals...

This is the toughest decision of all regarding the 915. I like to have a known history (see Tutorial), but without known mileage and type of oil used, I find that I replace the three P/S bearings, the three M/S bearings, and the diff carrier bearings routinely. One advantage that you have is that the mag case trans was actually easier on bearings than, say, the '84 Carrera. The 2.7 liter motor doesn't overstress the trans, and if the car is driven correctly, I would bet that bearings could go 300K + miles.

[SteveWig]

Ok, looks like new main and pinion shaft bearings.
Another question - if I swap out the existing open diff. for a ZF limited slip do I need to reset or check the pinion depth? I know I will need to check the carrier bearing pre-load but that is fairly DIY as opposed to the pinion depth.

[Peter Zimmermann]

Originally Posted by SteveWig

Ok, looks like new main and pinion shaft bearings.
Another question - if I swap out the existing open diff. for a ZF limited slip do I need to reset or check the pinion depth? I know I will need to check the carrier bearing pre-load but that is fairly DIY as opposed to the pinion depth.

In theory, if you replace the diff it's center will be in the same position as the old one. That means that the ring gear will also end up in the same position, so the pinion shaft depth should be OK. That said, I would not put it together without also checking/setting backlash as well as pre-load.

[SteveWig]

Thanks Pete, The Wiki is going to be indispensable. Thanks for your input and work on the Wiki