Rear wheels grinding when going uphill???

[Frixco_240]

The other day, I went to a muffler shop to weld on an Apex n1 muffler to my stock piping. ( I will be getting full HKS system when I save up enough). I live on a hill and when I was going home from the muffler shop, the rear end of my car started to make this grinding sound when I was going up the hill. Aside from the noise, I can feel the rear end kind of vibrate when it makes the noise. It kind of sounded like my muffler was scraping on the ground and it also sounded like it was coming from the whole rear end of the car. I checked the muffler and hangers and nothing seems to be hitting anything. This sound only comes when I have been driving my car for about 10 min, because the next day when I was going to school, the sound came back when I was parking and this wasn't on a hill. So this is basically what happened:

1. I went to muffler shop to weld on a muffler
2. Went home and it seemed like the whole rear end was grinding/vibrating while I was parking. Not squeling or just the sound, I can FEEL it grinding.
3. Went back to muffler shop to check if anything was loose and everything seems fine, nothing was hitting anything.
4. Next day grinding/ vibration came back after driving for 10-15 min. while parking at school.
5. Went home, and when I was parking again, the grinding/ vibration came back.

This is only from the rear end, or rear wheels, or muffler??? and it happened RIGHT after I welded on the muffler.
If it's not the muffler, what else can this noise/ vibration be. It only comes after 15 min of driving and when I'm tring to park. More serious when I park on hills. Tried searching and this seems to be a very unique problem, experience. Can it be wheel bearings? brakes? PELASE HELP.

[streetdk1]

it can be that your mufler is grinding against your drive shaft i had this problem befor check that out

[Frixco_240]

I really don't think it's any of the piping since i still have stock piping. the sound actually comes and goes. When I would put the car in reverse after 20 min of driving, the sound would be there. Then, I would take the car around the block to see if anthing happens while going in drive. (it's an auto), and no sound and when I put it in reverse after that, no sound again. It only happend when the car has been sitting. then, drive around for 20-30 min, put car in reverse, and the sound would be there. very strange. someone please help.

[Neejay]

Differential fluid?

[pbcstylez]

look under your car for wear marks in the rear, something is obviously rubbing

[Frixco_240]

I've search and searched some more and I think it's either the diff fluid, diff bushings? subframe bushings? or my rear brakes. I just had my rear pads replaced, and my rotors resurfaced about 2 weeks ago, but it never made the sound until right after I weld on the muffler????? this is killing me.

[Frixco_240]

bump. help please. :-/ :hsdance: :hs: :-/ :hsdance: :hs: :-/ :hsdance: :hs:

[aznpoopy]

that sucks

i suggest having a buddy drive the car while you poke your head around carefully and try to pinpoint it

otherwise u'll have to look for wear marks like someone said above