Rear end noise 2005 Baja Turbo MT

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Izzy
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Rear end noise 2005 Baja Turbo MT

Post by Izzy »

I am getting a grinding noise from what I thought was one or both rear wheels, but now I'm not sure if its coming from the hub area or the differential, or ?? ... but definitely something from between the driveshaft to the one or both hubs. Its a clear grinding sound with a frequency and gets worse when turning in either direction.

I replaced the brakes, rotors, calipers, and parking brake shoes and hardware. What I noticed when putting everything back together is that with all four wheels off the ground, the trans in nuetral, parking brake off, I could not spin either rear wheel. Thinking it might be the rear wheel bearings (or front) I put the car up with all four wheels off the ground and I cannot move the wheels up/down, left/right ... but I'm still not convinced its not a bad bearing. I can spin the front wheels a little and the brake drag stops them from spinning pretty quickly. The rear wheels will not spin like the fronts. In fact they wont turn at all unless I use a LOT of force, then I can spin or rather rotate the wheel slightly, but they don't spin like the fronts. Reading about how the LSD functions, I think I understand that that prevents the wheels from just spinning. Or I could be wrong?!?

My questions to those that I'm sure are way more knowledgeable than I am are ...
- With all four wheels off the ground, parking brake off, trans in neutral, should I be able to spin the rear wheels or does the LSD prevent this?
- I removed the calipers and rotors and noticed quite a bit of dust on the right side. Would bad bearings create dust?
- Should I remove the axles and/or hub to investigate the bearings and axles or do you think it might be the differential causing a problem?
- I have not yet been able to drain the rear diff ... waiting to receive a 13 mm square drive so I can use either a jack or impact on it.

Any suggestions would be greatly appreciated.
TIA,
-Izzy
Izzy
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Re: Rear end noise 2005 Baja Turbo MT

Post by Izzy »

While I'm still looking for any suggestions, I found this on the NASIOC site...

https://forums.nasioc.com/forums/showth ... ding+noise

A description of the exact noise and symptoms I am experiencing. This actually even explains all why I saw so much dust build up on the new parking brakes after I took it all apart to inspect. I'm gonna take the rotors off and check on this again. Boy, I'm actually hoping my problem is only the disk rubbing on the dust shield! ... I'll post back after I check it again.
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kamesama980
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Re: Rear end noise 2005 Baja Turbo MT

Post by kamesama980 »

If it's just the dust shield, that'd be nice.

You have a viscous LSD, it provides more resistance as the difference in wheel speed increases. wheels off the ground, it will try to prevent the wheels on that axle from spinning separately. there's another viscous LSD in the center diff so with all 4 wheels off the ground, they're making it so you're turning all 4 wheels together (or at least the rear two and something in front). with the front wheels on the ground, you're fighting the center viscous diff resistance in neutral and only rear diff resistance in gear.
-Russell
"You don't get to judge me for how I fix what you break"
03 sport 5mt
05 turbo 5mt vf39 and other STI bits, 3" turbo-back
ZUBAJA
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Re: Rear end noise 2005 Baja Turbo MT

Post by ZUBAJA »

It is possible to have a bad (noisy) bearing without having excessive play in the wheel / hub. The bearings are a double row ball bearing and one row can be making noise while the other row carries all the load. One good way to check for bearing noise is place a long screwdriver handle against your ear and the other end on the bearing housing (knuckle) and spin the bearing. To do this effectively, you might have to disconnect the drive shaft from the rear differential so that you are only spinning one (or one set) of hubs. The noise will be less without the bearing being under load. Dennis
Izzy
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Re: Rear end noise 2005 Baja Turbo MT

Post by Izzy »

FWIW - Looking at the dust shield in the area indicated in the NASIOC post I saw shiny area where rubbing was likely occurring. So I got my grinder and did a little surgery trimming the dust shield area that was shinny and finished it by painting it black.
The grinding noise did stop but only when going in a straight line. I still get a grinding noise when turning left or right though it is not as loud as it was before the surgery.
So having done this, I believe the noise is indeed related to the dust shield rubbing the rotors. I'm gonna drive it a bit including maybe doing tight circles for a minute or two in each direction then take it all apart again next weekend to see if I see any shiny areas again.
Izzy
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Re: Rear end noise 2005 Baja Turbo MT

Post by Izzy »

Wanted to circle back and give this issue closure, for me anyway. I have not gone back in a second time as what noise I still had appears to have stopped just by driving ... probably about 50 to 75 miles some of which was hard left and right turns. So my grinding noise was indeed the dust shield.
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kamesama980
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Re: Rear end noise 2005 Baja Turbo MT

Post by kamesama980 »

BTW, it's small and stupid but hasn't been mentioned yet, forget the "13mm square drive". Just get a regular old 1/2" ratchet and extension lol
-Russell
"You don't get to judge me for how I fix what you break"
03 sport 5mt
05 turbo 5mt vf39 and other STI bits, 3" turbo-back
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