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Thud when driving at speeds.

AZRockRunner

Nobody
Location
Tucson, Az
OK, Let me try to explain the jeep 1st, then the problem.
90 4 door
4.5" Rustys lift
1.75 coil spacers
Bar pin elim in front
33 x 12.50 R15 tires.
Ford 8.8 Rear axle with disc brakes.
No SYE yet, pinion at about 8 degrees

PROBLEM:
When driving the jeep, above 10 mph and the rear droops like over a bump or a dip, I hear and feel a thud in the right side of me and towards the rear.
It sounds like something is hitting the floor of the jeep. Now I can wheel this thing all day long and flex the heck out of it and never hear it. This only happens at above 10mph. It also happened before I put on rear shocks, so we can eliminate the bar pins on those being the problem.

I have touched every nut and bolt, they are tight. I dont see any signs of anything hitting the floor of the jeep, but man it sure feels like it and sounds like it.

Friend of mine thinks it could be the slip yoke in the transfer case but we dont know.

Any Ideas???

:wstupid:
 
Do you hear a thud or multiple thumps when braking hard?

When the axled drops, hard braking oir a bump the angle at the slip yoke increases. You could be exceeding the angle allowed by the slip yoke and it is binding.

Had that happen. I noticed it after an increase in lift height. But only when hard braking. The nose dropped and tail went up, increased the angle at the slip yoke just enough to bind. hear a thump, thump, thump. Found it by jacking up the rear and allowing the axle to droop, then tried to turn the drive shaft.
 
No, I can slam the brakes hard and nose dive it and no thud. Its only when the back end goes down, not up. I also am running a YJ Yoke for the increased angle.
 
One of your shocks are blown. Same thing happened to me, loud Thud like something was hitting the floor of the jeep over speed bumps. New shocks in the rear and its gone.
 
Read above, it happened before I put in rear shocks. I thjought maybe a leaf shackle hitting or binding????
 
Have tried testing your rear shackles for a bad bushing? My front end bumps, thuds, etc... when it flex at any speed above 10 MPH also, due to the bushings in the lower arms being worn out. This is just a suggestion. As for checking the shackle, try to move side to side and push/pull up/down. I have had one set of shackles that were bad because of wear and tear, and they failed the up/down test, but passed the side to side part. The bushing sleeve in the shackle was worn thin, and letting the shackle "bounce" on the mounting bolt. HTH
 
now that could be. I have new bushings in the leaf springs, as they are new, but the upper shackle still has the 1990 bushings in them.

I will change them and see what happens.
 
Let us know what you find out, okay?
 
I always update my posts. Thats one thing I hate, I find a post that describes my problem EXACTLY but its not updated and no fix. LOL

I will reply, but it might be a few days or so, I run my own business and this is the busy season.
 
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