'Snow Tire' noise between 5-35 mph on an 08

[SSovaiko]

]I have 'snow tire' sound between 5-35mph on an 08 3500 4x4 6.7 68RFE, all stock. It seems to be coming from under the center of the truck. I removed the front driveshaft while troubleshooting u joints and the noise went away. Spinning the transfer case output flange I thought I felt that output bearing or the chain sprockets rumbling, so I rebuilt the T case with a complete TransGo kit but found no wear anywhere, or bad bearings. Reassembled with all new bearings, chain, and sprockets, and still have that 'snow tire' noise between 5-35mph. It seems to correlate to driveshaft speed, not wheel rotation, and it's much louder in 4wd. Doesn't change with any gear selection or even coasting in neutral in the auto trans. Replaced outer left u joint that had some slight play - no change, no roughness in the hub, but when spinning the front diff and pinion flange it deems like there might be some slight roughness, but no play other than the usual gear backlash. No front axle leaks. All front driveshaft joints seem smooth, or have been changed. The double cardan joint has plenty of grease. But with that shaft removed, the noise goes away. I'm stumped, but am suspecting either the front shaft or the front diff. Any ideas to look for?

 

[bcbender]

You said the double cardan has plenty of grease but is it worn? I had a bad vibration on my 04, it was the front drive shaft, I took it to the local Fleet Pride truck repair shop (Greensboro, NC), and they replaced all 3 joints, rebuilt the cardan joint, balanced the assembly and I never had another problem, everything "felt" tight but I suppose the joints were a little worn. Have you tried driving around in 4HI, that would spin the internals of the T-Case w/o the front drive shaft. Front R&P is spinning w/o drive shaft so if no noise, probably not the problem (except from a small amount of back load from spinning the shaft and T-Case internals.) I would take a serious look at the front drive shaft, its an often overlooked source of many a man's frustration (and a dealer tech's "Cannot duplicate customer concern")

 

[Ozymandias]

I'd not recommend to repair an 04 front driveshaft as the design is severely outdated and was superceded by RAM at least 3 times.

 

[SSovaiko]

You said the double cardan has plenty of grease but is it worn? I had a bad vibration on my 04, it was the front drive shaft, I took it to the local Fleet Pride truck repair shop (Greensboro, NC), and they replaced all 3 joints, rebuilt the cardan joint, balanced the assembly and I never had another problem, everything "felt" tight but I suppose the joints were a little worn. Have you tried driving around in 4HI, that would spin the internals of the T-Case w/o the front drive shaft. Front R&P is spinning w/o drive shaft so if no noise, probably not the problem (except from a small amount of back load from spinning the shaft and T-Case internals.) I would take a serious look at the front drive shaft, its an often overlooked source of many a man's frustration (and a dealer tech's "Cannot duplicate customer concern")

I appreciate the ideas - I haven't tried 4H without the front shaft, but will try it tomorrow. I also have another front shaft that I can swap for a trial, I know it runs quiet/smooth. Either way I will pull the shaft and recheck, and likely send the 08 shaft it to my local driveshaft shop for checkout.

 

[SSovaiko]

I'd not recommend to repair an 04 front driveshaft as the design is severely outdated and was superceded by RAM at least 3 times.

Thx - Mine is an 08 - Do you know what years have the improved design?

 

[Ozymandias]

Latest part number, has 1350 ujoints all-around.

 

[SSovaiko]

Thanks for those pics! Looks like Mopar now lists the 52123326AD as their latest version, for $600. I pulled my shaft again to check all joints and it feels ok. But before splurging on the new shaft I thought I'd let my local driveshaft guy look it over - he thought the center ball in the double cardan was weak, and he also mentioned he was seeing yoke failures on the newest Mopar AC and AD shafts, he felt my older version was a stronger design. He's done many shafts for me over 25yrs, so I let him remind mine with 1350 joints and new center ball, and rebalance. He said my center ball was totally gone, as the spring had worn through the face of the ball due to lack of lubrication. I'll see if it fixes the noise when I pick it up tomorrow - if that doesn't work I have a line on an unused AC variant shaft for a good price.

 

[Ozymandias]

I got my AB from Rock Auto 3-4 years ago.

 

[SSovaiko]

Well, the driveshaft was NOT the culprit. I need to jack this up and get all 4 wheels spinning, and do a better diagnosis. My gut suspects the front pinion bearings or preload, or something else in the diff.

 

[SSovaiko]

SO with the truck on stands and running in 4WD at 30mph, the stethoscope revealed a noisy pinion bearing behind the flange. Yep, shoulda done that to begin with. I took the truck to my local diff shop for the rebuild, but the owner urged me to R&R the bearings myself and save about $1000 in labor, and let him coach me through the install/set up. So of course I tore the axle down today - I'll haul the diff parts in on Monday to see what he says. I found the backlash at only .001 to .002 around the ring gear, which seems pretty tight. And the tooth wear pattern looks odd, almost completely across the drive side of the pinion and ring - but that's without marker paint, so it's hard to be sure just yet.

 

[Ozymandias]

Put it together like it was, same settings or you'll end up with a noisy axle.
No matter how odd the settings are, the ring set is broken in to that position.

 

[SSovaiko]

Put it together like it was, same settings or you'll end up with a noisy axle.
No matter how odd the settings are, the ring set is broken in to that position.

Thanks, I agree - it has 220k miles in this position already. The tricky part will be getting the pinion depth to match before/after me bearings installed. I have an idea for a bolt-in jig to measure and duplicate the pinion depth below the carrier.

 

[Ozymandias]

Just use the same shims as have been in, you'll end up in the same position. Bearing manufacturing tolerances are way smaller then even the thinnest shim.

Shims are used to correct the manufacturing tolerances of the gear set, case and the carrier - more or less.

So you are good to go by just reuse the shims. Carrier and Pinion preload you know how to set? That's the only thing you need to care for.

 

[SSovaiko]

I've only set up 2 or 3 diffs over the years and have the factory manual on this one and most of the tools. Seems that the pinion crush to preload is critical, so I am not pulling this pinion today until I measure the current preload as a baseline - I only have a beam style 1/4" torque wrench but it should suffice.
Thanks for the input on the shim, that's helpful. I may still use the measuring jig just to verify the depth is consistent with old and new bearings.
The diff adjustment seems pretty simple with the side adjusters. I don't expect to change these bearings so I'm marking current adjuster position before disassembly, and will verify backlash and tooth pattern after reassembly and re-adjust as needed.
Any other advice? I appreciate it!

 

[Ozymandias]

I use a heavy impact for the pinion nut, so it crushes in smallest increments. Way more controlled then with a breaker bar.

 

[SSovaiko]

I can try using the impact, but I might get an extra crush sleeve just in case I overshoot.
On tear down yesterday I finally found the problem - the smaller outer pinion bearing had some pretty good galling on a few rollers, enough to score the race. The pinion had no play but preload was only 5in lbs. All other bearings look great I'll see what my mentor says but I assume he'll suggest just changing the bad bearing, verify gear pattern and backlash, replace all seals, and drive it.
Only thing that causes me a little concern is the race itself - it has witness marks in the case and back of the race where it may have spun in the case, no more than a turn, but I'm guessing when the first bearing roller sheared, it locked up on the race for a bit before the bearing finally broke free. The race is still tight in the bore, but I'll use some bearing lock fluid as a precaution.
This truck was a cvoid victim - it sat outside, unmoved for over a year and a half cuz it's owner was quarantined overseas. Im guessing that bearing was high and dry, and a few rollers rusted, leading to their galling. Or it just failed. But it's a Timken.. It does feel good to FINALLY find the source of this noise, though!

 

[Ozymandias]

Change that race no matter how it looks - it needs to be perfect perfect for the new bearing otherwise you end up at the same spot in a couple months. I never changed just the bearing without the race, i always do them both at the same time.

 

[SSovaiko]

Yes, the new koyo bearing and race are in, also changed the pinion head bearing. She's put back together for now, just need to final adjust backlash tomorrow, install new hub bearings and then test drive later this week.

 

[SSovaiko]

New pinion bearings/races cured the noise! I did open up the ring gear/pinion backlash just one notch on the carrier adjusters to achieve 0.004, as the pre-teardown 0.001 was just too tight for me. No whine so far but I really haven't gotten the axle to temp yet in winter driving.
The lesson learned here after chasing multiple rabbits is to get the dang thing in the air and verify the noise source(s) BEFORE diving into rebuilds and replacement. I was so *sure* I knew the noise source (three times !) that I wasted a LOT of time and $500 in parts on this one before finding the real cause. And thank you to my local differential shop owner who coached me thru rebuilding my pinion set up, saving me over $1200 in labor.

 

[petersonj]

@SSovaiko , thank you for posting not only that you solved noise problem, but how you solved the noise problem. So many times many members help out here, but never find out if anything they posted actually helped.

Thank you, again.

- John