This week I unhooked the driveline from the tranny to try and isolate my problem. I ran thru all four gears, up to 2000rpm, no noise. So I started examining my driveline (all three U-joints where replaced 100 miles ago) there was forward/back play in the yoke that connects to the pinion shaft. Then I noticed the pinion shaft nut which is supposed to be 160-280ft lbs, was finger tight!
Today I
tightened the nut, and installed a cotter pin, which was not used by the last person who worked on it, and went for a short drive through the neighborhood. So far No Noise!
If you have a Big Bolt it would not hurt to check and make sure you have a cotter pin installed.
