The Stovebolt Site Forums The Shop Area Driveline driveline noises

Yesterday I drove the truck (53 one ton) for the first time on the road, took it up to get safety inspection (it passed) about 15 miles. No problems on the drive up, but on the way back I started getting noise from the drive line. I didn't notice the noise until I was within about four miles of home, and I managed to get home with no problem other than the noise.

The noise is a very heavy, very noticeable while, but only occurs when slowing down or accelerating. No noise at all at steady speed. I'm hoping it's in the rear end, not the transmission (SM420 four speed). Happens in all gears except first, and it might happen then but I haven't driven it in first.

Parked the truck, bought new oil for the differential, and I'm waiting on getting the new gasket. Then I'll pull the cover, check out the inside and refill.

Is there anything I should specifically look for while I have it apart? I'll admit that the rear end and tranny are the only parts of the truck I didn't rebuild during the restoration. I had put about 15 miles on the truck before this excursion, all low speed on my road. Could the high speed run (I got up to 50 MPH at one point) have caused serious damage?

Tim