New Tires, Rear End Grumbles

jcmd · November 19, 2015

I bit the bullet and bought new tires yesterday, going from 245-70R16 to 265-70R16. When I was driving home, I noticed that the rear end is thumping between 10-30mph, mostly noticeable when coasting and not noticeable under load or acceleration. I have some noise above 60mph, but it seems like maybe just tread noise from the new shoes.

Did a lot of homework last night and read about slip yoke problems, could be u-joints, could be rear end bearing problems, etc. It bothers me because I never had any issues before the tire change. Previous tires were pretty worn down, but never had any noise. The noise is like "thump thump thump thump" and I was hoping for some opinions on what to check next. Any ideas?

Here's my To-Do list for the weekend:

- U-Joints

- Rear diff fluid change (needed)

- T-case fluid change (needed)

00Silverado4x4 · November 19, 2015

First I would go back to where you had the tires put on and have them verify that everything is good with the new tires. It's possible you got a bad tire or bad alignment. If you didn't have an alignment done I'd get that done. Then, if all checks good, proceed to troubleshoot.

jcmd · November 20, 2015

Thanks. I did get the alignment checked today and it's good, so that rules one thing out. I'm going to get the balance and tires re-checked tomorrow hopefully. I wiggled the drive shaft and it felt solid, but that doesn't necessarily mean the u-joints aren't bad (been through that before with other vehicles).

Another thing to note is that this is definitely a come-and-go thing. This morning it did it, but after work it didn't at all. I just went for a ride a little bit ago and it only did it for a tiny bit, but not much.

00Silverado4x4 · November 20, 2015

Keep us updated. I'm curious as to what the issue is.

jcmd · November 20, 2015

Another quick update. I noticed this morning that it will mostly do it when coasting around a corner going left. If I coast around a corner going left say 20-25mph, I can hear it very pronounced. Going in a straight line, not so much. I wonder why it would happen most often when I'm going around a left corner? Seems so strange to me.

00Silverado4x4 · November 20, 2015

In that case it may not be a bad idea to check your hub bearings on the front, just to rule out the possibility of a bad bearing.

jcmd · November 20, 2015

I never did think of that, but that would make sense. It certainly could be an acoustic echo off of the front. Thanks for the tip.

Nanotech Environmental · November 21, 2015

In that case it may not be a bad idea to check your hub bearings on the front, just to rule out the possibility of a bad bearing.

What he said...

A strong sign of a bad hub is a noise when cornering. If the hub is bad enough, you can feel the weight of the vehicle shift a bit in the corner.

Lift up each front wheel off the ground and grab firmly the top and bottom of the tire (at 12 and 6 o'clock) and try to shake it back and forth to the inside and outside. If it moves, you'll feel it 'clunk' a bit in the hub & it's time for a new one.

While you're at it, also do the same at 3 and 9 o'clock to check your tie rods, if the hubs don't move..

jcmd · November 22, 2015

I dove in this weekend and I think it was actually just some old fluid. I changed out the fluid and haven't heard a peep since. I also conquered the transfer case fluid change, but my fill plug head is pretty stripped. While I was able to get it off to fill the case with a pair of vise grips, I went to take it off again to check the level after a spin around the corner and it's too stripped to get it off again. Guess I'll be welding a nut to it the next time I change it. Bummer.