knock in the rear end?

[senorscott]

So earlier this week I had a 3 inch lift installed on my 98 4runner dd. The lift looks great and raises the truck to the perfect height, for now, but since the lift has been in, I'm hearing a knock coming from the driveshaft or the rear diff.
Everything underneath is solid. I've been under the truck many times since the knock started and nothing is rattling around or loose. The u joints are fine and the angle of the driveshaft isn't too bad. The knock is only there putting around town (stop and go driving). When I'm cruising on the highway the knock is gone. I've jacked up the rear end of the truck and put it in gear to see if i could find out exactly where the sound was coming from but it didn't knock at all. I've also had all the oil in the rear end changed but that didn't help either.
Has anyone else had a similar problem or any advice would help?

 

[SC T100]

I had a driveline clunk that was cured by greasing the rear slip yoke...there was very little grease in it. It seems the rear driveshaft was sticking and releasing on acceleration as the two pieces slid together. That may explain why you didn't get the noise with the rear end up...no driveshaft movement in the yoke.

 

[Mr Chuck Norris]

I had a driveline clunk that was cured by greasing the rear slip yoke...there was very little grease in it. It seems the rear driveshaft was sticking and releasing on acceleration as the two pieces slid together. That may explain why you didn't get the noise with the rear end up...no driveshaft movement in the yoke.

THIS.

The driveline slip yoke commonly gets sticky on these and causes a light clunk when stopping at or leaving a stop light. Grease the heck out of it. Same thing happens to mine occasionally, grease solves the problem for me.

 

[senorscott]

Okay, I took the driveshaft apart and greased the hell out of the splines, put it all back together and the clunk is still there just like before.

 

[SC T100]

Well, you didn't need to take them apart as there should be a zerk fitting for the slip yokes, but that stinks that it didn't cure the clunk.

Maybe a U-joint has gone bad. Also check the center support (carrier) bearing if you have one. It's the one with the rubber donut in the middle of the rear shaft (again, if the 4Runners have them).

 

[OverLand Cruisers]

While greasing our '03 DC the other day I noticed a leak coming from the rear DS slip yoke, the grease was almost the consistency of ATF.
The ds took a far amount of grease, still leaking a bit.
Weird.

 

[KLF]

This is the best grease I've found for driveshafts:

http://www.greengrease.net/

Very sticky and gooey, obviously very waterproof. It cured a slipjoint clunk in my truck. I have a special grease gun dedicated to the stuff. Sold at many parts stores.