5KTQ gear oil: 75W90 Mobil1?

["Evans, Nicholas" <nevans@geology.state.va.us>]

I've run Mobil1 synthetic gear oil (75W90) in a number of manual
gearboxes including 5-speed BMW motorcycle trannies, Norton 4-speeds,
New Process 435 4-speed truck trannies, Land Rover 4-speeds, and various
others.  In almost every instance there's been a noticeable improvement
in shifting, and less overall friction.  Any comments out there on the
implications of running this great oil in a 5KCSTQ 5-speed, center diff,
and rear diff?   Somehow I don't see myself purchasing Audi-brand oils
for this beast any more than I would go to the Ford dealer & buy
Motorcraft oil for the pickup.

Nick Evans
Mayflower Garage
Barboursville, Virginia
'87 5KCSTQ and a bunch of other stuff