01 outback rear end issues

[camel83]

having some issues in the rear end of my 01 outback. it has had a knock in the rear end for a while now. it is a four cylinder automatic with about 152k on it.

 

just had a bunch of work done on it, typical maintenance stuff nothing really out of the ordinary, noc sensor, brakes, fuel filter, transmission fluid drain and fill, etc. ive had it for about 20 months or so now.

 

it used to just knock when i put it in reverse. asked a couple mechanics about it and they didn't seem to think it was anything serious but its getting worse. i dont think its the transmission, but im certainly not much of a mechanic. it seems to be getting worse. i was recently on a road trip and had been on the highway for a couple hours and when i got into town and slowed down the car knocked really hard a few times that didn't sound good before it accelerated but it seemed more like a bind in the rear than the transmission slipping. it seems to knock now just accelerating but not all the time. sometimes it kinda jerks/shimmies a little while driving.

 

today i had only been driving for about five minutes and stopped at drive thru and there was smoke coming from underneath the car, couldn't tell exactly at the time where it was coming from but thought underneath the car seemed weird. when i checked a little further down the road it seemed to be coming from the rear axle on the drivers side but was pretty clear and wispy. there is a burning smell that was more prevalent in the drive thru. the car has always had kind of burning smell that i noticed since ive had it and ive put almost 20 k on it. now it doesn't seem to be too bad and no smoke or anything and no major burning smell. 

 

im taking it to my mechanic tomorrow but wanted to give him somewhere to start bc when i just say 'fix my car' that doesn't ever seem to completely resolve the issues i need fixed. its always more of a fix whats broken/what i tell him thing. 

 

there is also a subtle ringing sound coming from the rear end that has been happening for a couple months i guess. its really faint but im a musician and pay attention to how things sound, esp my car, im kinda paranoid about it lol. its def coming from somewhere in the rear end. 

 

so im thinking it could be a bearing, or something up with the rear differential. it might be a good idea to just replace the whole rear end with so many miles on it rather than replace all the individual parts as needed bc i imagine the bearings and stuff are getting worn out. i get parts and labor for pretty cheap but i just put almost a grand into it. but id rather deal with it then have bigger issues down the road. 

 

i guess it could be a universal joint, possibly? lol like i said im not much a mechanic just want to have some ideas on the best way to handle this. seems to be running fine for the most part now with the typical knocking. 

 

i dont know if all of these things are the same or separate issues but i they are ccoming from the same vicinity.  

 

thanks in advance for any advice. much appreciated. 

[forester2002s]

Could be a torn rubber-boot on one of the rear CV-joints.

The torn boot would fling grease from the CV-joint on to the muffler or tail-pipe, causing smoke (and a horrible smell!)

And the 'knocking' could be the CV-joint failing from lack of grease.

 

But it could also be any number of other things...

Edited November 13, 2016 by forester2002s

[1 Lucky Texan]

I wouldn't rule-out a frozen brake caliper - but??????

[blindrummer]

What kind of knock? Does it change with speed, cv axles are easy to diagnose. Check the boots, the click upon turning. subaru are known for leaking engines. My current 2006 leaks oil which drips onto the catalyst thus burning, i have to set my heater onto recirculate otherwise i can smell it, my 1996 also suffered this problem. Axle grease burning is a far more wretched smell.

Calm down on replacing the whole "rear end"

Could be wheel bearing or brake caliper

What kind of noise and when and how??

[CNY_Dave]

If the ringing sound was like a musical 'ping' when shifting D->R or R->D that's a classic universal joint symptom (front-rear driveshaft)