a thump noise every 20 to 30 sec. on 4x4

[fishnmaine]

Ive been having this noise for the last 2 years. While driving in 4 wheel every 20 seconds or so I have this thump noise.( this does not happen in 2 wheel drive) This is while driving in packed snow or ice with some tar showing on the road. When I'm driving in snow I don't hear it. I know I need to change my transfer case shifting motor. Because I've had some issues coming out of 4 wheel drive. sometime i have to drive backwards to release. it will release fine in snow going forward. but on tar and ice I usually hear a good thump noise. Now i don't use 4 wheel much maybe half a dozed times in a course of a winter. Now I know all tires should be at even wear on all fours but i will have to say my back tires are new and my fronts are 75% worn..Hope to hear some input

Thanks

 

[fishnmaine]

Is there anybody with transfer case knowledge here? Thanks

 

[JuBean]

Do you notice it while in corners or just after a corner? Sounds more like the axle loading up and then skipping a tire than a transfer case issue. You would only have that issue when the tires have some traction so when there is just snow the tire slides effortlessly.
Have you checked the fluid level in the transfer case?
The tire difference I would not expect to be enough to load the drive train up especially if you have open differentials.

 

[fishnmaine]

Do you notice it while in corners or just after a corner? Sounds more like the axle loading up and then skipping a tire than a transfer case issue. You would only have that issue when the tires have some traction so when there is just snow the tire slides effortlessly.
Have you checked the fluid level in the transfer case?
The tire difference I would not expect to be enough to load the drive train up especially if you have open differentials.

Nope going straight. Don't hear it when going slow like 15 to 20mph but 25 to 40 I hear it most. As far as fluid I haven't checked.

Thanks

 

[koda2000]

You're not supposed to drive in 4WD on surfaces where the tires/axles can't slip. If you have a tire that's low on air or if your tires don't have equal wear you load up an axle as stated. I don't think there's anything wrong with your t-case.