Noise from the rear of my GMT-400 ECSB 4X4

[napoleon.hardy]

I have been hearing a noise from the rear of my truck for about a month. Sometimes it was not there but within the last week it was louder and i could feel a knocking in my left foot when i had it flat on the floorboard. I jacked it up off the wheels and wiggled the driveshaft and the rear u-joint was bad. I went to No-Reilly and they gave me a u-joint that was suppose to fit i returned home installed the u-joint drove about 100 yards and it through the caps off the ujoint and the shaft dropped onto the cross member. I pushed it back home cussin and yellin the whole way. I went to Auto Zone and they asked a few more questions and I soon found out if you have an aluminum drive shaft there is another u-joint (I had no idea there were so many u-joints for our trucks) so i installed the u-joint tightened down the straps and checked it and the u-joint moved in the straps. So I assumed the straps were bad. I took them off and saw someone has put some extra weld material on the inside so they would hold tight. I went and purchased new straps tightened them up and thought I was golden. I backed out of the drive way drove a few feet to make sure it was not going to throw the caps and was happy thinking I was a master mechanic... Wrong! I put the ball joint press in the bed of the truck to return it for my $115.00 tool rental return and I heard the *** *** *** *** *** noise still. The faster I go the faster the noise goes. So a little more info I did a frame off partial restoration 1 year ago and had new brakes, drums, wheel cylinders, brake lines, portioning valve, shocks, fuel lines, and fuel tank. Any ideas would be greatly appreciated.

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[90halfton]

I would pull the shaft and take it to a parts house (not a chain store). The kind of parts house where every guy that works there is over 55 years old, is missing at least 2 fingers, and has had grease caked in his hands since he was 8, the exact age he started racing circle track. You know the kinda parts house I'm talking about. They'll be able to get an exact measurement and cross reference what you need for a ujoint. Go to a chain store and you're just as good off to walk to the back blindfolded, grab a random box, walk out, and continue driving home with the blindfold still on.

 

[napoleon.hardy]

Update... Pulled the cover off and found pieces of teeth missing from the ring gear and a loose pinion/yoke. So now the question is which is the best for a driveway mechanic. I see the parts for rebuilding the rear end are not super expensive but setting it up seems to take specialized tools to get it right and to even press the bearing on. My other option is pick up a used rear end and just slide it in. I have a limited slip now and I see some open rear ends in the $250 dollar range on CL. I am going to look around the site to see which year rear ends will fit under there. So I guess my question is: How hard is it to rebuild the rear end preload, spacing, shims, etc to get it right? I know rear ends can last basically forever if they are not abused, and I baby this truck for the most part, just not sure how hard the P O was on the truck... spent most of it's life as a farm (county truck). So any suggestions are appreciated.