I got caught in a snow storm this weekend and I used four wheel drive for a bit. I noticed a prety noticeable howlin noise when in fourwheel drive. Do gm trucks with the duramax/ali have a gear tcase or do i have something goin on?
Hey, I am new on here and this is my first post. I was looking for just this concern tonight. I was in the exact same situation this weekend. I was in a big storm and used my 4WD for the first time at highway speeds. I also noticed a hum as well as vibration which could be felt in the floor comming from the transfer case. It only did it when there was no torque on it. Under acceleration or decleration it was quiet and smooth. I took the truck to GM and took a service manager for a drive. He said that the newer trucks had more noise from the t-case once they got a few kms on them. I haven't checked the oil yet, but am thinking about switching it to synthetic. Maybe this will help smooth things out.
I had the same exact thing happen to me. I ended up replacing the entire front end and the noise was still there. I just had the fluid replaced in the transfer case and there was no metal in the fluid at all. the noise is still there. It did not start until I had around 33,000 miles on it. I was told to drive it for awhile to see if it gets worse. I don't know what else to do.
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