Noise under jeep - please help!!

[Armyspecial]

Hi all,

For some time now I've experienced a noise under my jeep which I cannot identify to fix. The sound is a metallic rubbing / vibrating like 2 metal surfaces rubbing and or banging together at high speed. It happens, and I think this is the important bit, when the engine is kept at a constant speed when driving. If I excellerate or decellerate the noise stops. It sounds like it's coming from the centre of the Jeep but could be echoing from the front or the back? I've been underneath and checked for anything that is loose. There is some play in the propshaft from the diff but apart from that nothing obvious. Any ideas....PLEASE!!!!

Cheers
Richard

[dinof]

First try checking the shoes on the E-brake. You could always back off that adjustment so they are clear from the drum. Let us know if that stops the noise.

[dfast]

Free play in propeller shafts, probably in cross joints are very good reason specially for vibrations, and banging sounds, so I would fix that first.
If something is wrong with transmission of transfer case it would be heard in other driving regimes, or problems with gear shifting etc..

[Farrell Fox]

[Post Deleted By Author]

[Tony W]

One mans LITTLE bit of play, is another mans full rebuild. If your diff is out of alignment it can make a noise as you suggested. Especially only on coasting.
Can you post a vid of the freeplay in the diff, and a look at the uni joints.
Tony

[Oilleaker1]

Check for worn front output on your transfercase. A common metallic noise due to wear. Not something that will cause problems, just annoying. Another quick check: look at your driveshafts to see if the ears on the shaft are in plane or the same. I've had Jeeps where the previous owner pulled the slider apart and then clocked them wrong when re-assembling. John