Yesterday...I heard a slight puttering sound like a 2 stroke motorcycle muffler sound...barely audible...thought it might have been a small exhaust leak.

Today it was a bit louder...I could only hear it under power...if I let off the gas the noise went down. As I got off the freeway, it changed to a very loud clunking sound...by the first street...my destination...I could now feel the clunking in the rear area of the truck.

I pulled over and check the U-joints they seemed ok...called for a tow because I didn't want to mess up the 3rd if was the u-joint.

I got home...jacked the rear axle up and spun the tires. I have a Detroit locker.
I could not see any binding in the driveshaft u-joints or feel any clunk.

I've never spun the tires before so I don't know what is normal. As I turned the rear DS tire...there seemed to be some play before the drive shaft or the PS tire turned....normal with a locker?

Should I try it under power?...Anything else I can do to trouble shoot?

I tried getting the filler plug off so I could check for metals but it won't come loose and it's starting round the corners....I shot it with pb blast and will try again.

 

Play is normal in a locker.
Have you checked the actual exhaust system? Wait until everything has cooled off and then get under the truck and tug hard on the various exhaust pipes, muffler, and all the hangers. Could be something broke and the pipes are flopping around or perhaps even hitting the wheel and being knocked around.

 

Ron,
I did check the exhaust it looks fine..

Any tips on getting the fill plug out without stripping the head?

 

^6pt socket of the correct size

 

Can't find a 6pt 24mm socket. Tried Sears Home Depot pep boys

 

Amazon

 

Try a 15/16 socket. It's only .17mm smaller, which means it will fit really tight and give you a really good grip.

 

I think 15/16 is what I used until I bought a set of larger size metric sockets. Try Harbor Freight with coupon.

 

I ended up using air tools...compressor wasn't working so I had to fix it first. I drained the oil from the diff, but didn't find any metal pieces.

Before I drained the oil I jacked the truck up and took a video of the u-joints and the diff while everything was moving.


When driving it feels like something is binding...you get the sensation of going over a speed bump.