My truck started to make grinding noise in low speeds, like 10-20mph. Today I drove behind a tractor idling 15mph with 2nd gear and I heard grinding noise coming from under the drivers seat. Noise is biggest at those low speeds and I think in 2nd gear. Transmission fluid looks ok and transfercase fluid is ok. Time to rebuild??? And it's 47re transmission. Thank you.

Wheel bearing?

I had a similar noise but it was at highway speeds and the only reason i heard it in the first place was because i was driving next to the k rail with my windows down. it turned out that the rear most u joint was wasted. i think it had some dust in there from the roller bearings..

 

i would be leaning towards transfer case myself. they are chain driven. ive never seen one go bad in these trucks but ive heard the noise when a chain driven tcase does go bad and its awful. idk how you would go about pinpointing the noise unless you got the truck up off the ground so that you can put it in drive and be underneath it and see and listen to everything operate

How about famous t-case snap ring?? What symptoms I can expect if it brokes?? Front wheel bearings seems fine, I wiggled both tires and no loose. Front axleshaft u joints looks old but there is no loose either. Frond driveshaft has little loose in that slide part ( don't know exact name ) but ujoint are good. But front driveshaft doesn't spin in 2wd am I right??

I dont know anything about the snap ring problem I havent seen it personally. But the t-case should only spin the rear driveshaft in 2wd and you should be able to spin the front one freely depending on how your front axle is setup but it should have the disconnect in it on the right side.

My guess would be either u-joints or wheel bearings. Transfer case could also be the culprit but I would think the noise would get louder with speed on the transfer case.

 

I would get all four corners up on jack stands and run at speed to troubleshoot further.

Not to mention you would have glitter in transfer case fluid.