06 3500 6-speed strange noises in 1st,2nd and reverse

[iplank]

06 3500 6-speed 4 wheel drive SB clutch and flywheel ... . am hearing noises in 1st 2nd and reverse. Don't hear anything in any other gear. Sounds almost like a bearing is going out but I dont know much about the guts of these things. I put 300 -400 miles a day on thing and have heard it for a bout a day and a half. Just curious if anybody has had any thing like this.

 

[Hoefler]

Most likely a rear counter shaft or main shaft bearing. Those two bearings have heavy side loads in the lower gears, as you shift up in the gears, the load lightens and transfers forward to the front bearings.

 

[AKaiser]

I thought mine was going out, but it turned out to be the rear driveshaft u-joints were going out, and apparently, that was causing some distortion in the driveline that sounded like the transmission.