[Jeff Lee]

My GUESS would be rear end. I have a Dana 60 with all MW parts. I'm about to get the Performance bearings package for the entire rear. I just need the shop to narrow the axle tubes, put new ends on it and get final measurements so I can get the new axles ordered. Previous axles were MW 40 spline with 11/16" rifle bore. New axles will be MW 40 spline with 1 1/16" rifle bore and 300M material. I'm also changing from 5:13 ratio to 5.86 ratio. Both the old and new ring gear are back-cut. The R&P will be coated (see last paragraph).
I'll take a measurement of torque to rotate the pinion before and after and post the results here. I'm not sure how or if I should measure torque at the axle? Don't expect this next week, this shop is slower than molasses! But we had a long talk yesterday and he's made a commitment to get the chassis & engine done by the end of this year. I'll believe it when I see it but I'm making a big push. I will push real hard to get the Dana up and ready to run. That also involves setting the engine / trans in the car with new motor plates to determine positioning of the Dana and axle size left & right. I'm not sure what MW's lead time is on these 300M axles. So just pushing for the rear-end to be completed will get the chassis well on the way to completion.

FYI - Same shop has had a hand in a customers vintage 4-cylinder road race car. After using a propriety coating on all bearings and bushings from front to rear (spindles, trans, rear), the car reduced lap times by 8 seconds. That's huge. He also believes that true ceramic bearings would be better yet.