If you power brake and your t-case shifter noticeably moves side to side, engine mounts are toast. May not be your entire problem, but it is A problem. You can also just watch it on heavy acceleration/blips of the throttle

 

I have not tried lifting the rear end or rotating tires yet, but here's another thought (considering any recent changes):

Could the vibration be coming from the front? A few weeks ago I replaced the both axle seals. As you may know this procedure, I had to remove the hubs (I replaced those), I replaced the drivers side axle u joint, I had to pull the differential gears, I had to remove the 4WD collar on the passenger side axle. There's also a carrier bearing on the passenger side axle to support the two-piece system. That's a lot a changes/adjustments.

If I had to point to anything I am concerned about, it would be that in order to put the differential carrier back in I used a dead blow hammer to tap it in place. I had to tap on those carrier bearings to move it in. I was doing it as gentle as possible.

And, I would also point to the new driver side axle u joint which was very hard to get out and put back in. The joint is a little tight but does not have a catch/hitch.

My gap in knowledge is if anything in the front could vibrate the transfer case shifter like it is.

Any thoughts about this are appreciated.

Thanks!

 

You can generally feel where the vibration is coming from. If you feel it thru the seat, its usually coming from the rear. If you feel it thru the steering wheel, it's coming from the front.

 

Meh, I doubt it. You can go drive around without the front d/s if you want, but I don't think you'll find anything.

When you're going straight the axle u-joints arent really doing anything (like speeding up and slowing down as they technically do at an angle)

Whaling on carriers and outer races to get them back in the pig is a time-tested shadetree tradition. As long as you were hitting it with something softer than steel, damage is unlikely

 

I thought about removing the front drive shaft, so I am glad you mentioned. Great thought about u joints, and yes, it vibrates while going straight. And... thanks for the shadetree wisdom. I used a plastic dead blow hammer so am probably good.

Just seems odd that the vibration shows up now after replacing the seals. Thank you.

 

All interested - I had time to put the rear up on jack stands and did some testing. Here's the rundown:

• Wheels spin like they should, no dragging of brakes or bearings
• Tread wear of the tires is normal and even. The balance is good.
• There is some slack in rear diff and transfer case when twisting the drive shaft. Seems normal from what I have gathered. There is no forward to rear slack when moving the drive shaft by hand.
• Re-inspected the u joints and the seals are in place and I don't hear clicks or crunches spinning it by hand. Recall that I have removed the shaft already and u joints moved like they should. I don't think they are the issue.
• There is no carrier bearing for the driveline. This is a one piece shaft.
• Brake torqueing reveals no twist at the transfer case shifter so I think the mounts are good
• Drive shaft weights are still in place
• No vibration in the steering wheel which is expected since the front is not in motion.
• No vibration through the seat.
• Rear differential works like it should. I used my phone video to isolate the sound and vibration.
• Vibration is up around the transfer case and transmission. I used my phone video to isolate the sound and vibration.
• Transmission has fluid and is red, it was rebuilt in July 2023.
• Transfer case fluid is full but is dark red to browning color. I suspect the transfer case may be the issue given the fluid color which would have been replaced in July 2023 too.

Next question is, is there a way to tell if the issue is in the transmission or transfer case now that I have it isolated? I had the transmission rebuilt in July 2023 so I want to make sure it is a warranty claim or not before I take it in.

Thanks.

 

Put the t-case in neutral, trans in drive, run the engine up to 2500 RPM or so, feel any vibration? Before shifting the trans or t-case to any other gear, shut the motor OFF, and give it a bit for things to stop spinning. Otherwise, rude noise ensue.

 

Did that! No noise with transfer case in neutral and trans in drive up to 3000 RPM.

With transfer case in 2H and drive the noise is back up to 2500 RPM or 70 MPH.

Would you conclude it’s the transfer case? I think so I just want to validate my thinking. Thank you for the help.

 

I would start with changing the fluid, and see what comes out. (make sure you take out the FILL plug first... to make sure you CAN refill it. )

There is also a snap ring on the output shaft of the t-case that holds the rear support being in place... that snap ring like to break, and allow the shaft to walk. Eventually, the t-case just blows up.

 

What will replacing the fluid do? Do you think the snap ring is something I should check on or replace?