My 1967 amazon wagon required a new transmission. I nearly lost the remaining gears on the return trip and had to tow it the last 150 miles home. I put it up on jacks pulled the old gearbox and dropped a replacement M40 in with fresh gear oil. After gettign everything bolted back up I took it for a drive. While the gears worked fine, I heard a "runk-runk" noise I had not heard on the drive home. I was concerend that I had installed something wrong, so I checked the driveshaft to gearbox bolts and discovered that they were a little loose. I tightened those back up and took it for another drive. The "runking" noise stopped, but noise continued to come from the rear-end. I first thought it sounded a bit like brakes scraping, but the rear pads were just fine when I pulled the drums off (didn't need to use a gear puller - lucky me!).

I put the rear en up on jacks and ran in in place for a while. There is definitely a noise comeing from the rear...someplace, I can't quite get it pinned down due to engine noise. The sound only occurs when the car is on motion. No noise when stopped. Shifting into neutral or other gears makes no difference in the tempo or type of sound.

My guess is that it's coming from the driveshaft or the differential, maybe the axles. I have been running some heavy degreaser under the car to get the leaked-out gearbox oil off everything and I wonder if I may have degreased something I shouldn't have. Any thoughts on diagnosis?