gear whine

[cupgt]

I rebuilt both my difs with detroit/TT, Ashcroft 4.12s, and all new Timken bearings. Set up was good, backlash good, pinion preload in spec but slightly on the high side (new bearings), pattern looked real good on coast and drive side. All was well and quiet. Now its started to get a good whine to it only when maintaining speed with very little throttle. More or less gas and it quiets down. Also whines a little when coasting to a stop at very low speeds. Any idea? Probably going to pull the rear end this weekend and give it a good look over and drive it on the front dif and see if it changes. Anything in particular I need to be looking at as a potential cause with the setup?

 

[helievacpilot]

How long did it run quiet before making noise? Did you Loctite the ring bolts? Sounds like something has moved. I did front/rear TT's & KAM 4.11's a few years back. Could never get the drive/coast patterns perfect, but pretty close. Not a peep out of them.

 

[cupgt]

I did forget to loctite the ring gear bolts which is the main reason the thirds are going to come back out. They did not make any noticable noise until the past couple weeks. Also I will say I'm not even sure if it is the difs or the TC or something else. We set them up with a beautiful pattern. Going to let my buddy who helped me set them up listen to it and see what he thinks. Going to wheel it Saturday and if the weather holds up pull the rear end Sunday and pull the ring gear bolts 1 at a time and clean and loctite them in and retorque. Ill also check pinion preload, backlash and roll another pattern. If its the tcase I'll just let it rip until she throws in the towel, I just dont wanna wreck new gears.

 

[AGH Sasquatch]

light throttle, low speed decel- sounds like pinion preload. I dont think i would drive it until i figured it out as what ever the cause=the part could be salvageable if caught quick.

 

[cupgt]

Well my buddy that helped set the difs up rode with me today and we gave it a good listen. Its def coming from the back half of the truck. Sounds like it could be transfer case. Nothing on the dif was remotely hot at all. Going to be pulling the rear 3rd and checking everything out.

 

[cupgt]

Pulled the rear axles and drive shaft and drove it today. Noise is def the rear end. Gonna pull the third tomorrow