Drive train noise

[Shawn Burns]

I recently completed a 14 hr round trip drive from PA to NC while towing a 7x12 enclosed trailer loaded with motorcycles and racing gear.

Upon returning, I can hear a metallic whine noise coming from the rear. I jacked up the rear on jack stands and let the truck idle in gear. I could not hear any noise coming from the driver's side wheel. A little bit of noise coming from the passenger's side wheel. The noise is loudest from the differential cover.

I had changed the fluid about 20k miles ago using valvoline synthetic 75w-140.

I changed the fluid again and it looked new. That made no difference in the noise level.

I was hoping that it was an axle bearing. I replaced both bearings. The passenger's side rattled around a bit more than the other side and I found metal shavings inside the outer tube. The diff cover was clean. I did not see any evidence of wear inside the difference.

The noise remains during my test drive. What else could the noise be? I'm thinking pinion bearing could be an option.

 

[rzr6-4]

1500 with LSD? 2500 with torsional diff?

 

[Shawn Burns]

Sorry 1500 with open diff. Crazy that a rebel came with an open diff.

 

[Ken226]

I recently completed a 14 hr round trip drive from PA to NC while towing a 7x12 enclosed trailer loaded with motorcycles and racing gear.

Upon returning, I can hear a metallic whine noise coming from the rear. I jacked up the rear on jack stands and let the truck idle in gear. I could not hear any noise coming from the driver's side wheel. A little bit of noise coming from the passenger's side wheel. The noise is loudest from the differential cover.

I had changed the fluid about 20k miles ago using valvoline synthetic 75w-140.

I changed the fluid again and it looked new. That made no difference in the noise level.

I was hoping that it was an axle bearing. I replaced both bearings. The passenger's side rattled around a bit more than the other side and I found metal shavings inside the outer tube. The diff cover was clean. I did not see any evidence of wear inside the difference.

The noise remains during my test drive. What else could the noise be? I'm thinking pinion bearing could be an option.

I've owned two 4th gen Rams. Both needed a pinion bearing replacement.

My 2010, when I owned it, had to have the pinion bearing replaced at around 100,000 miles. I was stranded in Farmington, NM for 4 days waiting for the parts and a "Tech", with the appropriate level of training to come up from Albuquerque.

My current 2013 started doing that a few years ago, at 70,000 miles. A local hot rod shop in Bellingham, WA rebuilt the differential with Timken bearings and seals.

It sucks and is expensive, but in both cases, the issue never came up again on that respective truck.

 

[Shawn Burns]

That's what I'm figuring. Sounds like a great excuse for a truetrack upgrade!

 

[Jeepwalker]

Put it back up on jackstands and push up/down on the rear driveshaft. Or have you done that already? Have your mechanic put a long broomstick to the pinion bearing area and the other end to his ear...and listen as the driveshaft turns..for bearing noises/grinding, etc. A guy might remove the wheels and driveshaft and rotate the pinion by hand and see how it 'feels'. Inspect the U-joint in case you have two things going on. Does this truck have a center driveshaft bearing? That's another source of noises and failures. Have your mechanic check that bearing with the broomhandle trick. Maybe that's the issue (I can't explain the shavings in the axle tube (axle bearings?). Maybe the center D/S bearing is the only issuue.

Pinion work:
Replacing the pinion bearings isn't too difficult. Based on your replies above, you should be able to handle it. Watch a couple "good" videos by guys who know what they're doing. Don't over think it, or think you need a lot of special tools (you don't) or get it 'just right' to the gnat's whiskers (you don't). Maintain shims where you took them out ...and the pinion washers. Measure the replacement bearing thickness...it should be the same as what came out. Before you tear into it, measure the pinion backlash...or even feel by hand...just to give you reference when you're finished. If you have a press, or know a guy who does (or buy the bearings at a parts store that'll press them for you) ....you need to press the new ones on. Cut the old ones off with a cut-off tool, b/c you risk the bearing assembly exploding all over the place if you don't get under it right during removal (I had that happen one time). Of course, inspect the side bearings/races.

I just usually put things back together with same spacers where they came out, new seal and crush washer ...and it's good. If there was a lot of backlash before you started, you can think about adding another shim to tighten it up a bit. Probably won't be on your truck. You can dust the gears and double-check your work if you want to, I usually don't unless I replace the side bearings too. Hopefully the shavings you saw aren't from the gears. The whole job is not as tricky as some guys make it sound and there is a lot of good internet help.

If you just need to replace the Pinion bearings, and you have a press lined up (or buy a H/F press..that works), the whole job ought to take a morning... since you've already done the axles. Beats leaving your truck at the dealer for 2 weeks only to have the tech to screw it up and call you ...and say it's gonna cost you $1,200 and 2 more weeks.


Tip: get a piece of 1/4 x 36" bar stock, 2" wide. Drill a couple holes in the end so you can attach it to the pinion and have the long end on the ground (to keep it from spinning) as you tighten the crush-washer.

Or you could take it to a driveline shop. I don't know that the dealer would do any better than you. I bet they would slap it together with the same shims anyway (well you couldda done THAT!!). Best of luck!

 

[Shawn Burns]

I will jack it back up to see if there is any play in the driveshaft where it meets the pinion. I know that I had the driveshaft off so that I could lube the splines in the spring. I didn't think of that. I want to make sure that my installation is holding. I do not feel any vibration, so that isn't too likely.

I don't remember there being a center driveshaft bearing in there.

Thanks for the help.

 

[Ken226]

I will jack it back up to see if there is any play in the driveshaft where it meets the pinion. I know that I had the driveshaft off so that I could lube the splines in the spring. I didn't think of that. I want to make sure that my installation is holding. I do not feel any vibration, so that isn't too likely.

I don't remember there being a center driveshaft bearing in there.

Thanks for the help.

It took me a few weeks of head scratching and crawling around under the truck to diagnose.

With it on jackstands idling, in drive, and the wife inside to keep the rpms up and the wheels spinning, I could definitely hear it coming from the diff.

But there certainly wasn't any play or movement in the back of the driveshaft. I also tried disconnecting the drive shaft, and tugging around on the yoke. Still rock solid.

I finally decided that despite any other evidence, to replace it anyway.

When the bearing came out, It was just a little rough with a small amount of rough texture on the races and some chips and rough texture on the rollers. Not enough to create and slop, but definitely enough to whine.

Obviously, replacing the bearing fixed the noise, it's been quiet and smooth for 3 years now.

 

[Jeepwalker]

Oh, I remembered something.... a while ago another owner posted a copy of a Ram service bulletin indicating some Rams ...the outer race on the carrier bearings have been known to crack, and produce noise (and I think a faint vibration??). His truck had that happen and they discovered it on a tear-down. Maybe you can find it in a search...or even a general google search.

Anyway, not saying that's your tk's issue, but it's another item to potentially investigate if nothing else jumps out at you. Or see if your truck falls into the range of the known build dates.