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View Full Version : Cracking noise under car



Elio S
24-06-15, 03:58 PM
Ok, my TJ has developed another problem. When I'm taking off from a stop or when I shift from 1st to 2nd gear there is a confidence shattering 'cracking' noise coming from under the car. From inside the car it sounds like it's coming from the front end, but with the door open, it's quite obvious it's coming from the rear. The problem seemed to have started a few weeks ago when I was going to slow for 2nd gear and it has gradually gotten worse to the point it sounds like something is about to snap, crack or fall off my car. I can't really duplicate it when it's up on jack stands, but I did notice the tailshaft and the standard transfer case slip yoke spinning out of round which would explain the shuddering I get on take off which has been there since I've owned the car. Oh and one other thing, sometimes I get a noise like a wheel bearing problem or a rock caught behind the backing plate of a disc brake set up. This noise is also coming from the back of the car. I can't tell if it's the transfer case, rear diff or the rear wheel bearings about to collapse. Has anyone else experienced anything like this?? Seems to be only when it's under the most load. Once you're moving at speed it actually feels fine.

Steve F
25-06-15, 10:24 AM
Check all the control arm bushes etc first, could be as simple as a rubber bush is binding up, this can create some weird cracking and creaking sounds and is most noticeable under load or change of load. Also check out the unis in the drive-shaft, if one is on the way out or damaged it can make all the sounds you mention and would also cause the out of round type wobble, this will happen quicker with a lift and no slip yoke eliminator as the angles get steeper and can put too much/additional load on the unis which will kill them.

Cheers
Steve

Elio S
25-06-15, 04:38 PM
Got underneath today and started pulling things apart. I found it pretty quickly once I dropped the tailshaft. The problem was caused by the rear uni disintigrating itself. It fell to bits as soon as I dropped the tailshaft. On one hand I was relieved it wasn't the transfer case or rear diff, but on the other hand I was a little cranky as I fitted that 'quality' Japanese uni joint just over a month ago

Elio S
25-06-15, 04:55 PM
Sorry double post