Need some input, friends. My daughter's '92 Legacy sedan AWD MT has developed an intermittent noise in the rear end. We thought it might be rear brakes but she took it to a mechanic today and he tracked it down to the rear diff. Checked inside and said oil seemed okay, no debris.

 

Any insights or suggestions? Anyone had a rear diff go bad? What's the best fix--swap in a used one? And how much work is that?!!

 

Daughter's in Spokane, WA and very sad. I'm in Honolulu and very frustrated that I can't run to help her fix her favorite Subie!

 

Thanks for any help. Aloha.

Differentials can live a long time making noise. If that were mine, I'd MONITOR it.

describe the noise.

 

swapping a used unit is very easy and very cheap and a great option as diff's rarely fail under normal use. like he said, they can go a long time without failing, giving you time to source a used one for $100 or less.

Spokane has a great Pull a Part yard and used diffs are under $50 if you pull them yourself. There are at least two members in Spokane who could help out your daughter on this.

Thanks for the quick responses, guys. You've put my mind much more at ease (and you know that means a lot to a dad!) Reassuring to know that we have some reasonable options and probably some time.

 

I'll talk to her later today and try to get a better description of the noise--it's not real loud, but it's enough to catch her attention and concern her. Will post back when I have more info.

 

USMB is the greatest!

Try some lucus gear oil addative. It'll help with the noise. Also be sure to get a dif from the same year and model or better yet verify the ratio before getting one as Subaru likes to change gear ratios.

The '92 rear diff should be 4.111 ratio for your daughter's manual transmission. Same as my '91.

I had a rear diff start making noise at 55k, drained it and put in Amsoil synthetic gear lube and put another 100k in it. still made noise but never failed

Mahalo--thanks--everyone for the very helpful information. Since it's not likely to lead to catastrophic failure we'll monitor it very closely for the next little while. Will suggest that she change the gear oil for now.

 

Grossgary--I really don't know what it sounds like, other than it's not a loud gear-crunching sound! She described it as a "revolving" or "rotating" sound, which made her think wheel/brake problem. Sometimes it's louder than other times.

 

Will keep you posted as we go along. Again, mahalo nui loa.

assuming the mech diagnosed the right thing,it could also be a wheel bearing in the rear,ask her if the noise gets worse while going around a turn in either direction.

Shipping a complete rear diff to Honolulu, Hawaii could cost more than the part itself, I have all the internal parts, most of these parts (except the outer houseing) will fit into a flate rate box from the post office, under $10 with insurance. I have an entire inner case on eBay, http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1,1&item=8035761852&sspagename=STRK%3AMESE%3AIT

I have sold over a dozen so far and have a few dozen left, The Datsun and dunebuggy crowd use them up. If you want one for $25 deliverd let me know. At this price you could just save it untill you need it.

assuming the mech diagnosed the right thing,it could also be a wheel bearing in the rear,ask her if the noise gets worse while going around a turn in either direction.

 

This is a more likely scenario. Diffs are tough little assemblies. But wheel bearings on these cars are a royal pain. 3 of 4 wheels replaced on my 96 Legacy around 100K miles.

The '92 rear diff should be 4.111 ratio for your daughter's manual transmission. Same as my '91.

 

Just to add a tid-bit to this. The 92-94 MT's have 4.111 final drive ratio, but the 92-94 AT's have 3.900 final drive ratio.

Really appreciate the continuing input, guys! Am beginning to wonder myself if it might be a bearing.

 

Unfortunately my li'l gal is stuck in bed with the flu and hasn't been able to get out and drive the last few days. But we talked about the bearing possibility--she'll let me know as soon as she has a chance to do some more listening.

 

Will post as soon as I know more.

 

Aloha.