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02-01-2020, 11:55 AM | #1 |
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rear end roar and "thunk"
Driving my '13 e88 yesterday I noticed a slight low pitched "hum" and a slight vibration coming from the rear end. The hum seems the loudest at about 30-40 mph. Along with that I noticed a slight "thunk" coming from the trunk area when ever I took a sharp left hand turn.
I shook both of the rear tires and didn't feel any wheel bearing play. I've not had a chance to get under the car yet, waiting for it to get warmer next week to take a look. Does this noise sound familiar to anyone? Car is basically stock with 49k miles on it. Appreciate any feedback if you have an idea as what the noise might be. |
02-01-2020, 02:54 PM | #2 |
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Check fluid for sure.
You shouldn't have the issue but, I'd boogered up the heatshield through the tunnel and it was rubbing on the driveshaft. Wasn't all the time and under braking was most noticeable. Just jammed a pry bar in there and wiggle it away slightly. |
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02-01-2020, 03:24 PM | #3 |
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I would have it checked out, it could be a differential or a driveshaft bearing, or a guibo. If these were to fail at the wrong time, it could be more expensive to repair due to collateral damage from failing driveline parts at speed. Or it could be nothing serious.
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02-03-2020, 03:06 PM | #4 | |
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Quote:
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02-04-2020, 09:41 AM | #5 |
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Gave the car a quick once over last night by putting it on some jack stands, killing traction control and putting it in drive for a slow roll. Got under the car and put my mechanics stethoscope on the outside wheel bearing hub and on the diff. The wheel bearings sound great, no noise. The diff is making some noise, but that may just be the nature of the beast.
I put the scope on the outside of the diff by the output shaft and both sides sounded the same. Also scoped the input by the driveshaft, but to my untrained ear, I didn't hear any grinding. I have some left over 75x90 redline gear oil and I'm going to change out the fluid tomorrow. Taking the day off since it's supposed to be warm here in NC. We'll see what happens from there. As for the noise, I grabbed everything I could while under the car with the engine off and didn't come across anything loose. Took the car for a quick spin around the block and couldn't reproduce the noise, so not sure what was going on. The hum and slight vibration are still there. While I'm changing out the gear oil, I'll swap the rear tires side to side and see if that changes anything. Stay tuned, more to come... |
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02-04-2020, 02:28 PM | #6 |
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Could be the trunk monkey:
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2008 135i, Jet Black, 6 spd, Canadian Sport package, black leatherette, manual seats, aluminum glacier trim, PDC.
1983 E21 Delphin, M10, 5 speed, LSD, MSW wheels, recaro seats, Hartge strut brace, rear sway bar. [SIGPIC][/SIGPIC] |
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02-05-2020, 04:03 PM | #7 |
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OK, gear oil replaced and rear tires swapped side to side. Not sure this did the trick, but I'll drive it for a couple 100 miles and see what happens and let that new fluid permeate everywhere. Not feeling confident this is the fix, but worth a shot. I'll post back up in a few days. My gut tells me it's heading to my indy for diagnosis and repair. The options combo on this car is rare enough where I want to keep it.
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02-05-2020, 04:40 PM | #8 |
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Sorry if this was covered elsewhere.
What's the production date on your tires?
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02-05-2020, 08:43 PM | #9 |
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02-05-2020, 10:09 PM | #10 |
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Ok do this next. Find a bump, like a driveway entrance etc. With wheel at full lock reverse slowly into it so one wheel hits the bump first. Listen for the knock/thump. Try again with wheel full lock other direction.
Hope this helps.
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02-06-2020, 03:43 PM | #11 |
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Not sure this is applicable to the E82, but in my 2006 Acura TSX, the rear sway bar endlinks would wear out every 50k miles and result in a loud clank when going over larger bumps. Could be something similar; a suspension piece in need of adjustment/tightening/replacement.
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02-06-2020, 08:57 PM | #12 |
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I can't reproduce the clunk, so that's really no longer an issue for me, but the slight roar and minor vibration are still there. Will drive it some more tomorrow to work in the new gear oil. We'll see if anything happens... Only have about 5 miles on it since I swapped it out. Too much freaking rain here in NC today to take it out for a decent spin.
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02-11-2020, 09:21 AM | #13 |
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Woke up early this morning and my brain started to wander and somehow slipped over the issue with the 128. Then I though about the center bearing on the drive shaft. I'm going to lift the car up again this evening and scope the bearing. It really makes sense in my mind that this is the issue considering the roar and slight vibration.
The down side to this is per realoem, there is no center bearing replacement, you have to replace the entire drive shaft, which is going to suck. Realoem lists those at $710. Back later this evening.... |
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02-11-2020, 09:44 AM | #14 |
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You might be able to find a driveshaft repair shop in your area who could do this rebuild, if that is the problem.
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2008 135i, Jet Black, 6 spd, Canadian Sport package, black leatherette, manual seats, aluminum glacier trim, PDC.
1983 E21 Delphin, M10, 5 speed, LSD, MSW wheels, recaro seats, Hartge strut brace, rear sway bar. [SIGPIC][/SIGPIC] |
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02-11-2020, 10:47 AM | #15 | |
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Maybe you just need to scroll down a little on RealOEM and there is an option for the components of the driveshaft. I picked a random 128i configuration and got here: https://www.realoem.com/bmw/enUS/sho...diagId=26_0217 |
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02-11-2020, 10:52 AM | #16 |
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Correct, if it is the problem. Will know later this evening after work. I'd have to shop around to see if there is any place local that could rebuild the center bearing. Maybe a breaker yard, but considering how few of these 1ers there are, don't have my hopes up for finding a used one...
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02-11-2020, 07:01 PM | #17 |
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wow, this is harder than I thought. The entire underside of car is covered. From what I can tell, I need to remove the exhaust, then the outer plastic under tray and then the aluminum heat shield. THEN I can get to the drive shaft to check the bearing. This isn't going well. I shudder to think what my indy is going to charge me to get those panels off and possibly swap out the drive shaft. Makes me consider getting a quickjack and getting under the car myself. Almost pay for the lift if I don't have to pay labor...
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02-12-2020, 10:01 AM | #18 |
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ok, another update. Talked to my trusted indy and told him I had checked the wheel and diff bearings and didn't hear any noise. He recommends driving the car until the noise becomes more pronounced. He said "no noise" was possible since the suspension wasn't loaded, there was no load force to make the bearing noise. Let it make more noise and then start rechecking bearings. It won't cause a catastrophic failure, only make more noise. His thought is there is probably a nick in the bearing surface that will degrade over time.
He said he's replaced plenty of wheel bearings but never a center bearing on the drive shaft. He has done the occasional rear "u-joint" on the end of the drive shaft, but he thinks one of the outside wheel bearings is the issue. So that said, I'll be driving the car for a while and keeping an ear out for the noise to get worse and then recheck the wheel bearings. |
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02-12-2020, 11:31 AM | #19 |
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You may have missed my earlier reply, but you can buy the bearing by itself:
"Weird that RealOEM isn't showing you the carrier bearing replacement, it should be part# 26121225071. Maybe you just need to scroll down a little on RealOEM and there is an option for the components of the driveshaft. I picked a random 128i configuration and got here: https://www.realoem.com/bmw/enUS/sho...diagId=26_0217 " Edit*: Adding link to useful reference thread: https://www.1addicts.com/forums/show....php?t=1212774 Last edited by dtla1; 02-12-2020 at 11:35 AM.. Reason: Added link/reference |
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02-12-2020, 12:58 PM | #20 | |
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03-19-2020, 09:41 AM | #21 |
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Wanted to update on this noise issue. Right now I have to say the vibration is less and the "hum" has diminished. As mentioned, the only change I've made is replacing the rear diff fluid with some red line. I'll keep and ear out for changes, but right now I'd have to say a simple gear oil swap has helped. More to come if anything starts to go south...
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