I have a humming noise comming from what seems to be somewhere in the middle (transmission??) or towards the back of the truck (rear end??). When I am driving and giving it gas there is no noise but when I let up on the gas the humming starts. I crawled under the truck this morning to check the u-joints and they do not seem to have any problem. But, by twisting the driveshaft back and forth there is about three inches or so of slack. Is this normal? I also checked the fluid in the rear end and topped it off using about 1 quart of differential lube. Would the rear end being about a quart low have caused something within to start making this humming noise? Thanks.
- posted
17 years ago