Rear dif?

4WRXter

4WRXter

Skier!
Since I bought my car I've had some noise from the rear. At first I thought it was tire growl. After the initial set of tires, winter tires, and new summer tires, it hasn't changed. MAYBE slightly worse. After doing a little reading and hearing Nigel say something about "rear dif whine" I think that may be the issue. I suspect that if I think it is rear dif whine, then it probably is.

Now, I know I'm not going to get an internet diagnosis for a noise. I have never ridden in any other RS, so maybe it is somewhat normal for 105k miles. I'll get it professionaly checked, or semi-pro from a knowledgable STMer if someone wants to ride along sometime, somewhere. But for the sake of conversation... If I was to source a used dif, how am I to be sure it is correct, and that a used one doesn't have the same issue.

Part 2: After skimming through a Haynes repair manual, I think replacing a rear dif is not something I should tackle alone in my dirt driveway. I've read that Big Ass Bolt is next to impossible to deal with. It seems the knuckles have to come off. (of the car, [probably 1 or 2 on the hands]) I would consider paying a reasonable wage to some of you experienced folks for your help. I don't want to ask for "favors", because I don't really know anyone here well enough. If someone has a paved driveway, garage, that wants to help me, PM me. Obviously, I would first need to get the dif, maybe bushings, etc etc.

 
If you want to come to the BBQ I for one will be more than happy to turn some wrenches. I have paved driveway, garage, tools, ect.

I am sure I am not the only one either.

 
When you read about "Squirting the big ass bolt" that's the bolt people talk about. Start working some PB blaster into it so you can ease it out a little faster. Otherwise, above-average vulgarities and bloody knuckles might occur.

I'm willing to pitch in, FWIW... :happy3:

 
diff whine I'm talking about happens at roughly 60-65 mph in top gear, under slght to medrate acceleration. it's quite distinctive, diff makes no noise until that speed, whines until above 65 and then tails off above that. the louder the whine, the more pooched the diff is. when it's time to a replacement, the noise is loud enough so you'd want to pull over and DO SOMETHING about it.

replacing rear diff is not a horribly huge job, just moderately involving. helps to have ahelper, preferably one who's done the job before. MUCH easier with a lift and tranny jack, tho not unpossible with normal jack and stands. you shouldn't have to undo that Big Ass Knuckle bolt, pull the strut instead and tip knuckle outward...there's just enough scope to get axle outa de diff

 
This sounds very similar to what happened in my car. The first 4.11 manual that i put in ($550 from norms) began making a whine/howl at various rpm's and engine loads after driving it for a couple months. soon after replacing it the rear diff started making the same noise :angry4: :argue:. It was a pita to replace but not entirely bad since the old 3.90 came out fairly recently. Lake region imports is one of the better places to find a decent diff too.

 
My old one was good when I had it. It did have a very slight whine at 71mph, but that could have been just the harmonics of everything doing their thing on the highway. Couldn't notice it unless the radio was completely off and the road was smooth and you were listening for it. Motul inside.

If by chance you cant get the long bolt out just undo the strut bolts and remove and pull down on the knuckle. You should be able to get enough flex to get the axle out with max amount of swearing. The long bolts usually come out if you hit it with an impact and pull on the bolt at the same time with an open end wrench just behind the head of the bolt. Once I had to hit the other end with an air hammer.

fwiw, every Forester and Impreza I did an alignment on I hosed the long bolts with PB Blaster to help reduce future long bolt problems. There are two permanent drool spots in my old bay at Patriot to proove it. Now, EVERYONE go out side and hose down your long bolts and nuts just becasue someday it will need to come out. Period. Let the PB pool up in the long pocket and just let it be. The PB will eat away at the rust, keeping that bolt and nut useable. PB it once a month.

John, make sure you dont have a bad wheel bearing.

 
So on Friday, I had to come down to Portland. I had someone ride along for a few minutes. That very reputable, knowledgeable person thinks I have a bad wheel bearing. I'll call the place where the reputable person works on Monday for an appt. to get it checked and replaced. That would be better than dif. I was looking to spend some money on the car, it might as well be for something that is truly needed.

 
def check the wheel bearing, mine had a whiny noise in the rear that Al was convinced was the diff. he even had me sourcing diffs. until he put it on a lift and I drove it while lifted. the diff was quiet but the WB was toast and showed no outward signs of being toast

 
So on Friday, I had to come down to Portland. I had someone ride along for a few minutes. That very reputable, knowledgeable person thinks I have a bad wheel bearing. I'll call the place where the reputable person works on Monday for an appt. to get it checked and replaced. That would be better than dif. I was looking to spend some money on the car, it might as well be for something that is truly needed.
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bad wheeel bearing makes the dreaded whoo-whoo or wumpwumpwump sound, often sounding louder when you turn slightly at normal road speeds.

bad R diff makes a distinct whine...no sound at certain speeds, then builds up quickly and then subsides.

 
So on Friday, I had to come down to Portland. I had someone ride along for a few minutes. That very reputable, knowledgeable person thinks I have a bad wheel bearing. I'll call the place where the reputable person works on Monday for an appt. to get it checked and replaced. That would be better than dif. I was looking to spend some money on the car, it might as well be for something that is truly needed.
Click to expand...
bad wheeel bearing makes the dreaded whoo-whoo or wumpwumpwump sound, often sounding louder when you turn slightly at normal road speeds.

bad R diff makes a distinct whine...no sound at certain speeds, then builds up quickly and then subsides.
Click to expand...
nigel, that is generally true, but no joke, my left rear wheel bearing made no wumping (ie, why Al thought dreaded diff!) no excessive play, just a whining from the rear of the car. Al actually had to use his mechanic stethiscope to listen to the parts to find the problem. the noise was horrendous!

both are definite possibilities either way!

 
So on Friday, I had to come down to Portland. I had someone ride along for a few minutes. That very reputable, knowledgeable person thinks I have a bad wheel bearing. I'll call the place where the reputable person works on Monday for an appt. to get it checked and replaced. That would be better than dif. I was looking to spend some money on the car, it might as well be for something that is truly needed.
Click to expand...
bad wheeel bearing makes the dreaded whoo-whoo or wumpwumpwump sound, often sounding louder when you turn slightly at normal road speeds.
Click to expand...
YUP! Not real loud whoo-whoo, but definitely a little louder in turns.

As stated, calling for appt on Mon. I've been listening, Nigel. I remember you saying how sometimes it seems that people will spend a bunch of money on "rice", and skimp on true repairs.

 
So, my rear dif turned into: wheel bearing and hub

head gasket

timing belt tensioner and guide?

and I need to replace the rear brake pads (that, I think I can do myself)

What I hoped would be a few hours, turned into pretty much an all day affair. So I rented a car from Enterprise and left mine in capable hands and came home to work. I got a brand new (44 miles) Ford Fusion. It looks a lot like the new STi. Ya don't need no stinkin' $36k hatchback. Slap on some EGay wing of some sort, and it's a mirror image. I keed, I keed. :bunny: I like the looks of the new STi better in person.

 
diff whine I'm talking about happens at roughly 60-65 mph in top gear, under slght to medrate acceleration. it's quite distinctive, diff makes no noise until that speed, whines until above 65 and then tails off above that. the louder the whine, the more pooched the diff is. when it's time to a replacement, the noise is loud enough so you'd want to pull over and DO SOMETHING about it.

replacing rear diff is not a horribly huge job, just moderately involving. helps to have ahelper, preferably one who's done the job before. MUCH easier with a lift and tranny jack, tho not unpossible with normal jack and stands. you shouldn't have to undo that Big Ass Knuckle bolt, pull the strut instead and tip knuckle outward...there's just enough scope to get axle outa de diff
Click to expand...
Holy raisin that is exactly what my car has been doing for a few months now. Do you think its cooked? Would a fluid change help?

 
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