Transfer Case/ Transmission

I have a 2002 w/ 180,000. 4.8 Auto/4x4. Reg. cab long bed. I've noticed a few noises when the truck shifts from 2nd gear to third. It seemed at 1st to be the tranny. The noise can be described as a "clunk" as if metal is getting tapped by a hammer. I thought maybe something wore out, being that it has electronic actuators) Not real hard, but I can hear it every time it shifts. It hasn't gotten any worse since the summer, but I've also noticed some issues with vibration at 40 mph and 60 mph. When I'm in 4 wheel drive, there's no clunk when it shifts. The vibration is always there. If I hammer on the gas or if I'm turning sharp in wheel, there is a decent amount of clicking coming from under the truck. When I shift out of 4 wheel drive, the clunk comes back after a bit. I'm thinking the transfer case has issues. As far as the vibration at 40 and 60, it's not the brakes. I rebuilt them. The tires and wheels are both new and I had them rotated and balanced.
Your thoughts:

I have a 2002 w/ 180,000. 4.8 Auto/4x4. Reg. cab long bed. I've noticed a few noises when the truck shifts from 2nd gear to third. It seemed at 1st to be the tranny. The noise can be described as a "clunk" as if metal is getting tapped by a hammer. I thought maybe something wore out, being that it has electronic actuators) Not real hard, but I can hear it every time it shifts. It hasn't gotten any worse since the summer, but I've also noticed some issues with vibration at 40 mph and 60 mph. When I'm in 4 wheel drive, there's no clunk when it shifts. The vibration is always there. If I hammer on the gas or if I'm turning sharp in wheel, there is a decent amount of clicking coming from under the truck. When I shift out of 4 wheel drive, the clunk comes back after a bit. I'm thinking the transfer case has issues. As far as the vibration at 40 and 60, it's not the brakes. I rebuilt them. The tires and wheels are both new and I had them rotated and balanced.
Your thoughts:

anytime you hear clunking on shifting the U joints are #1 item. with the rear wheels off the ground check the u joints also the drive shaft spline bushings for wear..vibs also means its bad....

anytime you hear clunking on shifting the U joints are #1 item. with the rear wheels off the ground check the u joints also the drive shaft spline bushings for wear..vibs also means its bad....
I changed the U joints.

only time your gonna feel a vibration from your brakes is when your on the brake pedal. as far as the clicking u joints would have been my first guess to, did you check your front ones for any play, not sure if your truck actually have front u joints or not (correct me if im wrong), its possible the vibration could be your driveshaft out of balance and if it is a bushing like j cat said then that can cause the vibration.

I changed the U joints.

did you mark the drive shaft before installing ? I use spray paint , this way it goes back as it was...since it is still clunkiing , then you must re-check the U joints that you just put in ...who is the manufacturer of the U joints...

since you replaced the U joints did you notice any wear issues at the spline ends ?



clunking on moving from a stop I found to be the transfercase ,bushing needs some lube...the replacing of the transfercase fluid with TRAC II OEM PRODUCT USUALLY CURES THAT ..when you did the U joints did you lube the splines on the tail pieces ?

I have a 2002 w/ 180,000. 4.8 Auto/4x4. As far as the vibration at 40 and 60, it's not the brakes. I rebuilt them. The tires and wheels are both new and I had them rotated and balanced.
Your thoughts:

on the vibration this could be a wheel weight that fell off...

when in 4WD it is normal to get some vibration..since its at 40-60 usually the tires....if it does this at all speeds it could be most anything..like bent axle, defective tire, rim , drive shaft bal wts , different sized tires...

If you operate this in 4wd on dry pavement you with your milage may find it may indeed be the transfercase worn..check the fluid it should be blue,,,if gray its needs fluid replacement ,,if black the clutches are going...gone....

did you mark the drive shaft before installing ? I use spray paint , this way it goes back as it was...since it is still clunkiing , then you must re-check the U joints that you just put in ...who is the manufacturer of the U joints...

since you replaced the U joints did you notice any wear issues at the spline ends ?



clunking on moving from a stop I found to be the transfercase ,bushing needs some lube...the replacing of the transfercase fluid with TRAC II OEM PRODUCT USUALLY CURES THAT ..when you did the U joints did you lube the splines on the tail pieces ?

It's not the U joints. That's the 1st thing I did, I should have told you that. I didn't notice any unusual wear on the spline ends, but I didn't really look all that hard. These clunking noises and the vibration all happened before and after the U joints were changed. I usually start with the easy, less expensive route. There is a vibration that happens in 2 or 4 wheel. There is 2 different clunkings happening. 1 is every time it shifts from 2nd to third unless it's in 4 wheel. I though maybe something wore on a actuator. The other clunking happens when it's in 4 wheel, under stress and sharp turns. That clunking seems to have a steady rhythm. It sounds a little like a half shaft when they wear, but louder and seems to be in the center of the truck under it. I've a lot of work on Chevys, but the Tranny and transfere case are beyond my understanding. I've never had to deal with it.

on the vibration this could be a wheel weight that fell off...

when in 4WD it is normal to get some vibration..since its at 40-60 usually the tires....if it does this at all speeds it could be most anything..like bent axle, defective tire, rim , drive shaft bal wts , different sized tires...

If you operate this in 4wd on dry pavement you with your milage may find it may indeed be the transfercase worn..check the fluid it should be blue,,,if gray its needs fluid replacement ,,if black the clutches are going...gone....
I had the tires rotated and rebalanced. The tires are all the same size and under a year old. I will inspect the fluid next. Is this a big project? What about the clutches?