Ok guys I am confused on what the noise like a moan or groaning or humming (hard to explain) noise that seems to be coming from the rear....it only does it when I am in motion....its stops when the truck is not in motion.....I have a 00 F150 supercab 4x4...

Any thoughts as the noise is about to drive me NUTS!!!! Thanks in advance!

 

Rear end? Check bearings and the gears

 

When was your differential fluid last changed? Checked the fluid in the transfer case? Also may want to check the u-joints.


-MColford

 

Your friction modifier (assuming you have a LS differential) and gear oil is probably worn out. If it has some miles on it, its time for a change. They can make noise.

 

This past weekend I had the fluid replaced and had 2 bottles of friction modifer added as I was getting some shudder and that fixed that issue.....it seems the noise goes way after 30mph but that could just be my imagination.

 

Check your driveshaft, u joints and rear brakes.

 

Does the noise occur both forwards and backwards, vary by speed?

-MColford

 

Not sure if it would make a difference, I would imagine so.. It only calls for 4oz of modifier for the 8.8 and 9.75. If you used the motorcraft modifier, they are 4oz bottles, which means you put to much.

 

it does seem to occur both forwards and backwars and seems like i cant hear it anymore after i get above 30mph but maybe i am just not hearing it......also you know when you park and shut the truck off and go to get out when you let off the brake the truck will roll forward a little bit well it makes it then also a little when the truck moves.

 

I would check your parking/emergency brake.

 

i have to slightly disagree, i had a bad noise coming from my rear. so much i thought the gears were going bad. had my tech do a diff service with the everwear products from our store. he used the everwear friction modifier. when i still had the noise, i called the dealer pricing up gears, when the parts guy told me they just had a guy in there with the same problem as me. he put in 4 bottle of Ford friction modifier (not anything generic) and his problem went away. i figured as long as nothing was damaged inside, i would try it. but i was only able to buy 3 since the guy came back & bought most of their stock for his other truck and that's all that was left. my tech filled accordingly then put all 3 bottles (and that stuff stinks, lol). and wouldn't you know it, i haven't had a problem since.

 

I have an 01 SuperCrew 4x4, and I just had to replace the rear end. The truck would "jump", or sound like it was grinding or locking up while I was making turns at first; then it started doing the same things while I was driving straight. Definitely check out the rear and good luck!

 

Putting that much modifier in may get rid of the noise, but it will essentially turn your LS into an open diff.

 

when you changed the fluid you should have checked the play in the gears, the carrier cover was open itwould have been the opertune time. also why were you changeing the fluid. unless you have a leak or excessive miles you should never have to change it.

 

The reason i was changing is it has 178,000 miles and i was getting a bad shudder when i would turn from a stand still and it has corrected the shudder but still have the noise....and I was listening closely tonight and i dont dont hink it does it in reverse only going forward does that make a diffrence?