Another "what's this noise" thread

[Tom, F&L GoR]

This is my 3rd Viper, so have a lot of experience and patience. It's a 2008 coupe with 47,000 miles and I replaced a mechanically failing RR wheel hub in August. (The metal bearing seal cover had been worn through from the inside because the cage failed, so not only were some ball bearings free, but the metal cover rubbed on the inside of the knuckle and grease running out.) The repair went fine. Over the last few weeks, I have a similar rubbing, chafing, metal on metal (or like dense rubber) squeaking noise from the same area (right rear?) that is correlated to vehicle speed, not engine speed or driveshaft speed, but I can't find what's causing it.

I inspected all four brake calipers to make sure pads weren't rubbing. I see the 2-piece rotor hats sometimes catch the inner edge of the pads, so filed the pads.
I backed off both parking brakes and haven't used them. They are very far from rotor.
Lifted rear wheels, set on jack stands, started engine, and ran 1st through 4th gear at engine idle speed for quite some time - no noise.
OK, maybe noise was really from the front, so changed RF bearing, wasn't that. Could it be LF? I must be really deaf...
My previous Vipers had U-joints, so I've pushed and pulled on these CV joint shafts, and while they go in and out of the differential, there is no rotational slop.
I thought the RR replacement wheel hub was defective, so replaced it again, no change.
I can replace the LF bearing because I have one and replace the LR with the one I took off, but not optimistic.

Is there a similar noise from a half shaft that feels tight? Or from a differential side bearing or seal? There aren't any differential oil leaks, but another step is remove the belly pan and get a better look.

Any idea is appreciated.

[Tom, F&L GoR]

Also, no vibrations, no pop or click noise. It's a metal on metal(?) noise that gets drowned out at speed but noticeable below 25 MPH, especially out of gear and coasting, all the way until stopped. No smell, no hot spots.

[Steve M]

Based on what you described, I'd suspect something in the differential, like bad pinion or carrier bearings.

[ViperSRT]

Any change with steering input or turning?

[Tom, F&L GoR]

Nope, only vehicle speed. Thanks, ViperSRT.

[Tom, F&L GoR]

I don't like you anymore, Steve M. But thanks, differential is on the radar. I have "good" wheel hubs and will change all those first because I have them and I'm now good at it, also because the sound isn't grinding like other old differentials I've had. Can't tell, and why I'm asking.

[Steve M]

I only say that because I went through something very similar on my daily driven truck ('07 Toyota Tacoma) a couple years ago. It was a squeaking, grinding noise that sounded like it was coming somewhere from the rear, but I just couldn't quite pinpoint it.

I ended up replacing the cheapest stuff first, working my way toward the more expensive stuff. That ended up being a full u-joint replacement on my 2-piece driveshaft, the center support bearing for said driveshaft, and even the brakes on both sides. None of those things ended up being the issue. I finally ended up supporting the rear axle on jack stands, removed the wheels/tires, and put it in drive while I crawled around underneath while it was running (not the brightest idea, but I was out of ideas). It was at that point that I was able to attribute the noise to the rear differential.

When I went to drain the differential fluid, it was sparkly, so I knew one of the bearings was going. I'd recommend doing the same before you go too terribly far with this...if your differential fluid is relatively clean (i.e. not filled with glitter from a disintegrating bearing), you can probably rule it out.

Not sure if your CV joints could be the cause, but it'll be worth checking the boots while you are under there just to make sure.

[ViperSRT]

Sounds like you have eliminated anything up front then. And in doing so the differential carrier components should have responded to the turning as well. I don’t really understand how the diff pinion or side bearings would be quiet without road load (on jack stands) and noisy under coasting. When you ran it on jackstands were the jackstands under the suspension or the frame (that is suspension loaded or unloaded)?

[Martyb]

Are you sure it’s not the inside pad on the ebrake? I know you mentioned you backed them off, just hoping it’s something simple. Best of luck Tom, if I was near by I would come over and help track it down. You have been such a huge asset to our community over the years, I feel obligated! Again, I hope it’s something simple.

Marty

[Tom, F&L GoR]

Steve, I also had it on jack stands in the rear, took the wheels off, put lug nuts on to hold the rotor tight. Engine on, put it in first through fourth gear, and all was quiet.
None of the CV boots are bad, cracked or have tears. Yes, I'm going cheapest stuff first, or what parts I have left over (i.e. Gen 2 front hub = Gen 4 front hub.)
Checking the fluid is a good and cheap idea, thank you.

BTW, somebody at Dodge? decided the plug in the center of the front wheel hub needed a huge nut and stamped the threads. Even so, the nut could come loose before coming to the upset threads. Use a dremel tool to remove the damaged threads (can do this at your bench) to be able to remove the nut without stripping anything. That part of the threaded plug (plug itself does nothing in Gen 2, only holds ABS ring in Gen 4) is external to any clamping, so don't worry about it.

ViperSRT, yes the noise (almost groaning) does not change with turning or not. It also doesn't change with accel or decel.
The jack stands were under the frame, so another test is putting them under the suspension, thanks.

Marty, I used my old 40mm caliper piston retracting "socket" so there's a huge gap between both inner and outer pads. Thanks.

[Grcforce327]

Possible diff/pinion bearing. The gearset noise itself would change between on and off the gas. Bearings make that deeper tone, and get worse with speed... even going at speed with the engine shut off.

[ViperGeorge]

Steve, I also had it on jack stands in the rear, took the wheels off, put lug nuts on to hold the rotor tight. Engine on, put it in first through fourth gear, and all was quiet.
None of the CV boots are bad, cracked or have tears. Yes, I'm going cheapest stuff first, or what parts I have left over (i.e. Gen 2 front hub = Gen 4 front hub.)
Checking the fluid is a good and cheap idea, thank you.

BTW, somebody at Dodge? decided the plug in the center of the front wheel hub needed a huge nut and stamped the threads. Even so, the nut could come loose before coming to the upset threads. Use a dremel tool to remove the damaged threads (can do this at your bench) to be able to remove the nut without stripping anything. That part of the threaded plug (plug itself does nothing in Gen 2, only holds ABS ring in Gen 4) is external to any clamping, so don't worry about it.

ViperSRT, yes the noise (almost groaning) does not change with turning or not. It also doesn't change with accel or decel.
The jack stands were under the frame, so another test is putting them under the suspension, thanks.

Marty, I used my old 40mm caliper piston retracting "socket" so there's a huge gap between both inner and outer pads. Thanks.

You state that all was quiet with the wheels off. This would seem to indicate the noise has something to do with the wheel. Are your calipers hitting wheel weights? I had a noise in my 06 coming from the rear. Took it to the dealer. The tech replaced wheel hubs, ebrake pads, and checked everything, noise was still there. He ended up finding a piece of metalic insulation had fallen and was rubbing on the driveshaft. Gen 3 and 4s are pretty much the same so maybe you should check that there isn't some insulation rubbing on something. Although if the noise is gone with the wheels off I would still focus on the wheels.

[Steve M]

You state that all was quiet with the wheels off. This would seem to indicate the noise has something to do with the wheel. Are your calipers hitting wheel weights? I had a noise in my 06 coming from the rear. Took it to the dealer. The tech replaced wheel hubs, ebrake pads, and checked everything, noise was still there. He ended up finding a piece of metalic insulation had fallen and was rubbing on the driveshaft. Gen 3 and 4s are pretty much the same so maybe you should check that there isn't some insulation rubbing on something. Although if the noise is gone with the wheels off I would still focus on the wheels.

I'd think as long as the rear wheels are of the stock 19" variety, there would be little chance of the wheel weights hitting the calipers. It'd be much more likely up front with the 18" wheels since there isn't nearly as much clearance.

That reminds me though: what about the battery? Vipers do all sorts of weird things when the battery starts going...

[Tom, F&L GoR]

Thanks everyone for the patience and good ideas. Made me rethink and retry stuff. I jacked it up, took the rear wheels off, start engine, ran it in 4th gear and the left rear wheel had a click in it. Not bad or loud, but different from the right side. Made me think of the toy ball bearings on the strings that hit each other and the motion perpetuates for some time, except that the click was not nearly as sharp. More of a click with plastic cushions. I guessed wheel hub and replaced it.

20201126_134311.jpg

Looked reasonable from the outside.

20201126_134421.jpg

Looked reasonable on the inside... whoa! Not supposed to come apart!

This is exactly the mode of failure on the left rear only back in August. whatever keeps the bearing together on each side lets go and while nothing can come apart, water can get in. The outside ball bearings are starting to turn yellow while the inner balls are clean.

Moral of the story - can't tell if they're bad by looking, can't tell when they are rotated with no load, and hard to tell left or right side from the driver's seat. Good news is that it's a 45 minute or less repair. The limiting factor is getting your torque wrench in between the shock forks to tighten the four bolts holding the hub on. Tightening the large axle nut isn't hard, but you might as well only put two lug nuts on the wheel when you do it, because you'll have to take the wheel right off again to attach the retaining cover and cotter pin.

Thanks again, everyone.

[Steve M]

Awesome...glad to hear it was something "easy".

Did you just replace them with OEM parts? If so, what was the part number and approximate cost for each?

[Steve-Indy]

Happy to see you solved the problem, Tom.

Steve M said: "That reminds me though: what about the battery? Vipers do all sorts of weird things when the battery starts going..." which I thought was hilarious, if not masterful. Happy Thanksgiving to All !!

[Tom, F&L GoR]

Steve, truth be told, since this is not a track car, only my commuter car I used MEVOTECH H513109 for the RR in August since I've used other front suspension parts from them in the past with good results. Because I thought this cheaper brand had failed, I replaced the RR hub again with SKF BR930045. Since that didn't fix it, I put the used MEVOTECH on the LR and problem is gone. Both were from RockAuto.com; MEVOTECH for $46 and SKF for $88. By comparison, the Mopar part is $363.

Heads up. I think Gen 1 and Gen 2 hubs were same front and back, but Gen 4 front and rear are different. For the August swap, I had to send back a hub because of that mix up at RockAuto, but they were as good as they could be about it. They have a warehouse on Long Island, so for my location it's 2-day service.

[J TNT]

Wow good find Tom , Thanks for sharing !!!

[Rocket]

Thanks for sharing. I'm approaching the same mileage with my 09 - so something to keep an ear on.

Did you look at your Stabilizer Bar Link Bushings when you were there? I did a brake pad change last week and noticed mine were shot. At least there is not a huge Viper tax on the replacement links.

[JonB ~ PartsRack]

Mr G2 Caliper TOM H !!!

I just now saw you on the scene again, and WELCOME

Glad you kept your super-secret royal title: F&L GoR. Well deserved your excellency..........

JonB