Driveline noise/vibration

[JimT]

So, been monitoring this for a while now and seems I don't know enough to figure it out on my own.

Changed carrier bearing back mid-winter of 2020. Prior to this there was no noticeable driveline noise/vibration. Immeadiately after shop changed the bearing (I didn't own an impact at the time) I noticed something. Mainly up around 45-50 mph +. It was slight. I also had aging steer tires, wearing out front springs and bushings and haven't had an alignment. I chocked it up to a slight misalignment of the new bearing. It was subtle and I wasn't too concerned at the time.

Fast forward 9 months to mid-fall. Had a drive tire blow out. Took out part of my full rubber fender and damage my step box but nothing else. Replaced with a new tire, Bridgestone 726 ELA. No change. A few weeks later I replaced 4 of the remaining drive tires (so 5 new, 3 old) with Brigestone M710. Had them rotated as such:

[]---------[]
.......||.......
.......||.......
[][]------[][] <------ 4 new tires (26/32)
[][]------[][] <------ mix of 3 old tires plus 1 new (7/32, 10/32, 10/32, 32/32) (Don't remember exact pairing)

Ever since these tires were installed I've had a noticeable driveline noise while driving. It started immediately after the tires were changed. I'm not great at describing noises. It's only present when driving. It's not from the engine. It's most noticeable when applying positive power to the driveline. Coasting or slowing it goes away. If I take the transmission out of gear it becomes much quieter, but it's still present. It is rhythmic, but not constant.

Finally, just prior to shutting down for the holiday it started making more noise when I turn the wheel in one direction (I think to the right). Even the slightest adjustment in that direction will result in the same noise. My first thought was maybe it was a power steering issue, but as above it only happens while driving and under acceleration.

So, I'm stumped as to where to focus my investigation. I know the transmission has had it's share of abuse but I'm not sure if that's the source. Gonna replace all the u-joints (see below). Haven't looked at wheel bearings yet, but as the symptoms are not constant I don't think they are the culprit. I am (finally) replacing my front springs/bushings, but I don't expect that to solve the problem.


My U-Joints are sealed/non-greasable and most likely have 600,000 miles on them. After seeing the damage to Rawze's truck from a failed u-joint I'm planning on just replacing them all proactively. (Not sure the expected life, but it looks like they only carry a 500,000 mile warrenty) They very well could be the source, as all signs do suggest changes to driveline angle have contributed (carrier bearing replacement, tire replacement/rotation).

Dealer (Peterbilt) looked up the parts and quoted just over $1,300 for all driveline u-joints. Said I need 4 CP25 and 2 CP20. After some searching online I come up with Meritor CP20RPLS and CP25RPLS along with Spicer parts 35-RPL20X and 35-RPL25X.

Does anyone who's dealt with this know if I'm actually looking at the correct part numbers? Plus, other then a $50-$100 price difference between brands (Spicer is cheaper), is one better then the other?

Any help or insight would be appreciated. It's a 2012 Pete 587, 13 speed trans, 3.36 rears.