Poping in the rear end

[BRAD6160]

I did a quick search and did not find anything like what I have going on. There are similar issues that I found.

Anyway I have noticed the longer time goes on the worse it has got. I get a poping noise from the rear end when turning. I only does it when I a pulling a load....the heaver the load the worse it is. The sharper the turn the worse it gets. It does not do it going down the road when turning just when you are in a parking lot or turning around/making a u-turn.

How long do rear diffs last?? 2000 F-250 3.73 Limited Slip 300,000 miles. everything still origional. I replaced the rear yoke seal @ 60,000 miles.

I had the rear u-joint fail around the same time (@70,000 miles) snapped 2 bolts off in the rear yoke. 1 came out with the easy out the other had to be drilled an retapped.

Any ideas what it could be?? it is not any u-joint because I just had the rear fail this weekend(had @50,000miles on it)...replaced the u-joint and still does it. All u-joints and center bearing have been replaced 1 time the rear joint had been replaced 2 times now.

[BRAD6160]

Ok so I took diff cover off to see if I could see anything obvious wrong...did not see anything. Changed Fluid w/friction Modifier and greased the slip yoke. Havent had a chance to pull a heavy trailer yet. Just pulled a 4500# trailer and no popping when I turn real sharp.

One thing I did notice I pulled up to a small hill in our yard (with just truck and no trailer)to check and see if both rear tires were pulling and only the drivers side wheel was spinning. I am guessing that would be clutch pack issues??