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.

[Precisionw900]

I just went through this fight with a truck. Rebuilt driveline, new slip yoke and all. New brake drums all new tires. Alignments you name it I did it. What I finally found was output bearing on transmission was loose. Surprisingly I couldn’t feel anything pulling on output shaft when drive line was down. Once driveline was reinstalled I guess with the added weight hanging I was able to push up on yoke and feel slack. Remember a drive shaft acts like a large stethoscope. I can really amplify a vibration. Is your vibration high frequency? Drivelines usually are fast vibration and anything wheel end related is a slower heavier type vibration

[JimT]

fast or slow... not sure off hand. Haven't driven since before christmas. I am leaning toward something driveline as opposed to wheels. I'll get under there and check out what you mentioned as it's a logical candidate. Thanks for the reply!

[Chamberpains]

What the hell kind of matching are you doing there? Sorry, but you have to know that that much difference in tire size between the 2 axles, plus that 1 tire at double the tread height of the rest is gonna throw your axle ratio/tire rotation out of sync. Your axles are constantly fighting each other. Get your tire height matched between the 2 axles and hope you didn't burn up your differentials to much.

[Rawze]

Chamber called it spot on ...

New tires on one side, and worn tires on the other .. or new on the front (or rear_) and the other axle has worn down tires ... and the spider gears in the differential are going to be constantly spinning fast to keep up with that mess. Also the driveshaft between diffs is going to work harder with new on the front and old in the back.

Just mentioned this. i would never run old and new tires in combinations on the back end of my own truck knowing this. - I always have a matched set... and if I have to replace one tire, I replace the entire set.

That may or may not be your issue but it certainly does not help, nor is it the best thing to do.

[JimT]

(01-08-2021 )Chamberpains Wrote:  What the hell kind of matching are you doing there? Sorry, but you have to know that that much difference in tire size between the 2 axles, plus that 1 tire at double the tread height of the rest is gonna throw your axle ratio/tire rotation out of sync. Your axles are constantly fighting each other. Get your tire height matched between the 2 axles and hope you didn't burn up your differentials to much.

Thanks Chamber, Rawze.

I was thinking that I was still very broke after my inframe and couldn't actually afford ANY tires, but knew I had to do something before I had more tire failures. The remaining 4 will be replaced very shortly and that one oddball new tire will become a spare. Honestly, didn't think the difference between the axles would be that significant. I was more concerned with matching up tires on the same axle. At the time 4 tires was the absolute max I could manage (aka .

Probably be another 2-3 weeks (although I'll call now and see if I can get approval through our national account sooner) before I can replace the remaining 4.

Is there a better way to remount the existing tires until I can finish replacing them?

Also, any opinions on the u-joints? Meritor vs Spicer? Spicer's seem to run about $50-100 cheaper. They are a well known name, but I don't have any first hand experience with them to help make a decision between the 2. Did I get the part numbers right? Dealer just said CP25 for the front and CP20 for the rear.

[alborz]

Check the height of your truck. Depending on your suspension type, truck height is different from center of axle to frame. If a difference exists that might creates an imbalance angles between drive shaft and pinions and causing the dragging like noise when speed passes 50mph. But first you need to fix the combination of old and new tires.

[Chamberpains]

I'd start by draining the rears and seeing what comes out. I fear you chewed a crush washer or burnt a bearing up in 1 or both of those rears. You need to know they are alright 1st. If not you're OOS. Ive been there done that on 3 rears across this country and none went out anywhere close to home. The hotel and down time getting the rear in to wherever it goes out is the crappy expensive part. They can be done in a parking lot by hand but you had better have biggest smartest set of big boy pants on board to do it. Other than that its a tow bill and the mercy of whoever wherever to get the job done. Its better to catch it now then go any further.

Next is get those tires matched up as close as possible. Even if it means buying cheapy's till you get the money saved up for proper ones. Refer back to what you just read for the reason why. Take the short term hit so that doesn't happen.

As far as the uJoints... ive gotten 800,000 and much more out of those non greaseable 1's. So you have some time if money is tight. If I were you I'd save up to have the entire drive line taken out. Everything replaced and properly spun balanced. Also coraseal and por-15 it all for another go round of a good chunk of a million miles. Keep a close eye on everything till you pull the trigger on pulling it all out. Use a huge bar (3' or longer) to pry them around for play. Also grab them with your hand to feel if they click or clunk.

[JimT]

(01-08-2021 )Chamberpains Wrote:  I'd start by draining the rears and seeing what comes out. I fear you chewed a crush washer or burnt a bearing up in 1 or both of those rears.

Added to my todo list. Anything in particular that I'd be looking for, other then just metal/debris?

(01-08-2021 )Chamberpains Wrote:  Next is get those tires matched up as close as possible.

Called, waiting for approval on the national tire account to replace the remaining 4.

(01-08-2021 )Chamberpains Wrote:  As far as the uJoints... ive gotten 800,000 and much more out of those non greaseable 1's. So you have some time if money is tight.

I can get all 5 (not 6 as mentioned in the OP) U-Joints (Spicer brand) shipped to my home for about $675 which is currently well within my budget and changing them out is easy enough with my own tools. It may be early, but I see it as cheap insurance.

(01-08-2021 )Chamberpains Wrote:  Use a huge bar (3' or longer) to pry them around for play. Also grab them with your hand to feel if they click or clunk.