Ive been getting the sense that there is some slack in my driveline so i crawled underneath to inspect u joints and found this.

 

It's the slip yoke, which is supposed to extend and contract. It appears normal to me, but I haven't looked at mine in awhile. I wonder if its getting hung up? You sitting level when you took this picture?


Edit: picture from last Aug. Little bit of weeping

 

So THAT'S what that is.
I've been wondering what that was. No thread-jack, but thanks. :P

 

OP there will always be a bit of slack in the ring & pinion, AKA backlash. Without enough of it your gearset would overheat and eat itself, but too much will cause excessive wear. Anyway you shouldn't worry about that, but you said you checked your U-joints for slop. If they had any, I'm sure you know to replace the offenders. Grease is your friend, so squirt it into that fitting until it comes out through the seals.

 

No slop in them. I will grease them though. Should i be worried about that seal though? It appears to be partially seperated. So an inch to inch and a half of play is normal or is that to much? This all came about cause every now and then i fell a tug in the rear like i hit a decent bump but there is know bump cant of hard to explain. Almost as if everything shuts off for a spliy second.

 

Can you describe better how the thump occurs?

At constant speed?

Accelerating?

Decel/coasting?

Braking?

Check out other possible areas of slop, like the ubolts for the leaf springs, the schackles, the bushings, etc. Hmmm, what else?

Can you reproduce the thump whenever you want?

 

It kinda sounds like what was happening to me. When I would start from a stop i would feel it kinda like roll and it would thump. It was coming from the rear and I had to get it rebuilt. Hope that's not your issue

 

I cant reproduce it. And its only happend a few times so i havent had much of a chance to anylize it. It seems to do it deceling or coasting or right after i lift throttle though. I have been suspecting that my diff is getting worn out. I drained and chandlged the fluid in it last year and the PO had filled it wih ATF...

 

Ohhh that's bad. You are probably looking at a rebuild then. Probably cheaper to buy a used whole axle if that floats your boat.

 

Have you checked your U-Bolts and spring perches?