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Front Differential whine = exploded transmission?


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22 replies to this topic

#1 telpernian

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Posted 04 April 2006 - 08:10 PM

Is there such a thing as a "transmission differential" ? My dealership is telling me I've had problems with my Front Differential. They've confused me by first saying the two things were different, then saying they were the same thing.
I understand what the F. Dif. does, but not how it works with the transmission. If I were having a problem with "bearings and seals" in the F. Dif, should I expect a massive transmission failure?

If you're curious about the background to this question, this is my sad story:

I have a 2001 Forester (automatic) that I bought used from this dealership in 2004. It's been in fine shape, considering its current 130K miles. It's a basic country commuter car that's made a lot of 3-5 hour trips.

Since last August, any pressure on the accelerator resulted in a whine that grew in pitch as the car sped up. Three separate sources said "it might be your front differential, it'll just get louder, don't worry about it." Three!

The sound did indeed become louder, until a new deceleration sound developed. Again, we were told by mechanics that this wasn't a great concern. It's just the front differential bearings wearing out. They suggested cutting the AWD for the summer to quiet the noise. They suggested the following repair eventually:

"Will need to remove to remove transmission to determine if front differential bearing are the cause. Estimate $975 P/L to remove transmission. R & R needed bearings and seals in front differential."

Two weeks ago, this was the advice we were given by our dealership. We took one long trip with complete success and commuted 50 miles daily for two weeks.
On our last trip, we hit slow traffic, and while in those lower speeds (30-40), the car began to buck and shudder. While scrambling to get off the interstate, the front end began to bang viciously, and the front wheels periodically locked. Thus, the "exploded transmission" (their words).

What's got my goat is that until now, my dealership mechanic has only expressed modest concern. After towing the car back to them, they expressed great surprise and said it was "incredibly rare." Now that we're taking our repair elsewhere, they say it was what they expected all along. (Naturally.)

We've only been given information concerning the front differential. No warnings concerning actual transmission. I'm not a car person. Was I expected to understand they are the same thing?

From my limited readings and conversations, it did not appear that a modest problem with a front end differential could result in an exploded transmission.
Was I horribly naive?

So many thanks for your thoughts: feel free to email me directly at jade.entangled@gmail.com

~Telpernian

#2 Brumby Boy

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Posted 05 April 2006 - 04:08 AM

eather way your up for some money unless you can get one from the wreckers and fit it your self unless you can find that the dealership somehow is at falt

#3 chanpaul

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Posted 12 April 2006 - 08:38 PM

Since last August, any pressure on the accelerator resulted in a whine that grew in pitch as the car sped up. Three separate sources said "it might be your front differential, it'll just get louder, don't worry about it." Three!

The sound did indeed become louder, until a new deceleration sound developed. Again, we were told by mechanics that this wasn't a great concern. It's just the front differential bearings wearing out. They suggested cutting the AWD for the summer to quiet the noise. They suggested the following repair eventually:

"Will need to remove to remove transmission to determine if front differential bearing are the cause. Estimate $975 P/L to remove transmission. R & R needed bearings and seals in front differential."


Ouch!

Well I experienced the same issues with my 2001 H6 VDC, with almost exactly the same problems. The whine got louder and louder, and then I started noticing it on deceleration too.

I did end up replacing the entire transmission before it "exploded" though ... we had it up on a lift and you could see the whole unit vibrating really badly. That was my warning ...

Hang in there!

#4 nipper

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Posted 12 April 2006 - 11:24 PM

Is there such a thing as a "transmission differential" ? My dealership is telling me I've had problems with my Front Differential. They've confused me by first saying the two things were different, then saying they were the same thing.
I understand what the F. Dif. does, but not how it works with the transmission. If I were having a problem with "bearings and seals" in the F. Dif, should I expect a massive transmission failure?


The front differential is built into the transmission case. Once it goes bad, you replace the tranny. Yes you had all the symptons of a dying differential. On some vehicals it is so loud it sounds like a jet plane is in the next lane at highway speeds.
Your gears are eating themselves up, or have been eting themselves up. The gears have a lot of meat on them, so it takes a while for them to get where the car wont go anymore.
Did anyone ever check the fluid levle in this differential? It is extreemly rare for a differential to go in these cars, or for any car for that matter.
It doesnt matter if the seals or bearuiings went, as it is too late now.
My guess would be a leaky seal and you lost the lubricant, the rest is history.
The transmission didnt explode, the differential self destructed. SInce the differential is part of the tranny they can say the tranny exploded. Trust me you are not going to need just bearings and seals, but the entire differnential too.

nipper

#5 carlosg

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Posted 05 February 2010 - 07:21 PM

Thank you for your info. I have a Legacy 92 in a god shape but I had this problem with the transmission. The noise of the bearings inside the differential.
Is the differential a separated part from the transmission?
or do I have the buy the whole transmssion?
I was thinking that I just need the bearings of the differential to replace them. But I don't know if i could get those.
If you know where can I get the differential or just the bearings, please let me know.
If you think that I need to buy the whole transmission, please advise also.
Of course I need to know where If you know.

Thank you

#6 grossgary

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Posted 05 February 2010 - 07:42 PM

the transmission and front differential are essentially an assembly. it is very rare to separate them but possible. that's why you can hear both ways "they're the same"....or "they're not".

in general the labor and parts to repair a front diff....and then the possibility of further damage means very few people are going to repair a front differential. that's totally acceptable.

also Subaru automatic transmissions are extremely reliable and therefore used ones are cheap. last one i bought from a yard was $150, 100,000 miles, with a 3 or 6 month warranty. that's super cheap and not the going rate, but the point remains the same - transmission failures are rare enough that getting a used one is a good option. get one from a wrecked vehicle - then you know it was good!

when you can buy a perfectly good trans for a couple hundred it just doesn't compare to rebuilding a front diff where you have to measure and adjust backlash and pay for parts.

#7 Fairtax4me

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Posted 05 February 2010 - 08:16 PM

get one from a wrecked vehicle - then you know it was good!


Assuming that the car wasn't wrecked to get insurance money because the transmission was failing. :lol:

Yes the front differential is built into the transmission case. It is separated from the automatic transmission in that is uses it own fluid.

The reason they said keep driving it, is because the cost to repair worn differential bearings is more as replacing the transmission itself. Basically, you drive it until it blows up, then get a new one. If you repair it, you may end up with other problems associated with taking the transmission apart, which may render the car just as useless as a blown up differential.

#8 Gloyale

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Posted 06 February 2010 - 11:47 AM

Just for the hell of it

Make sure you haven't just broken a CV joint in one of the front axles.

It can act just the same as a broken diff.

It is also very possible to replace just the front diff.

All you need is the bearings, a ring gear and a pinion shaft and a few seals.

No need to throw away a good running and shifting 4EAT if it is just the diff that is broke. It's expensive....but in the long run a better option than simply "dropping in" another unknown condition used trans.

Edited by Gloyale, 06 February 2010 - 11:53 AM.


#9 davidsain

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Posted 02 November 2013 - 07:10 PM

I know this is an old topic, but I've experienced this failure twice now and thought I'd share the answer. 

 

The front differential is in a housing attached to the front of the transmission called the Torque Converter Clutch Case Section.  The input shaft shaft passes through this case (inside of the Seal Pipe) - the provides motive power from the engine to the transmission which is then transferred back to the Center Diff via the pinion gear shaft.  

 

R&R requires removal of the transmission and removing this Torque Converter Clutch Case from the front of it.  This does NOT require disassembly of the transmission as another poster suggested unless one wishes to call this case removal "disassembly of the transmission".  As long as the pinion shaft seal between the diff and the transmission has not been compromised, it's doubtful there is any damage to the innards of the transmission.  

 

The whine is caused by damaged teeth on the ring and/or pinion gears.  Once a couple of teeth have sheared off, you get the big "thunk" when the pinion gear turns and hits a mismatch in the alignment with the ring gear.  It's a fairly costly repair - around $1000 to replace the gears and bearings.  When draining the transmission, it is recommended to see if there is any loose metal in the fluid that may have bypassed the seal and damaged the transmission.

 

As I've experienced this twice in my 2000 roo that 237K miles on it, I am wondering why this happens.  It's an automatic, so there's no dropping of the clutch to add extra punishment to the center diff.  These gears should be strong enough to last the life of the car.  In all this time, I've never experienced any issue with the rear diff.  I do have a hard shift between 2&3 when the transmission is cold that's been there since I bought the car in 2006.  Maybe that's part of the problem...

 

David


Edited by davidsain, 04 November 2013 - 09:29 PM.


#10 presslab

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Posted 04 November 2013 - 09:55 AM

 
As I've experienced this twice in my 2000 roo that 237K miles on it, I am wondering why this happens.


The replacement ring and pinion was probably not set up right. How long did the second one last? Did it have a faint whine noise after it was fixed? There are shims and preload adjustments that must be done correctly to ensure long life from the final drive.

I doubt the hard shift has anything to do with it. That sound like a problem with the high clutch.

#11 davidsain

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Posted 04 November 2013 - 09:34 PM

The replacement ring and pinion was probably not set up right. How long did the second one last? Did it have a faint whine noise after it was fixed? There are shims and preload adjustments that must be done correctly to ensure long life from the final drive.

I doubt the hard shift has anything to do with it. That sound like a problem with the high clutch.

 

Presslab, this was setup about 100k ago by a Subaru dealer (Kevin is a good mechanic) and was quiet as could be.  For a couple of weeks it started humming and then exploded one night last week.  I'm driving my old chevy truck for now, but considering just getting a pulled trans which is way cheaper than doing another rebuild.  Probably fix the hard cold shift too.

 

Maybe I should just yank the engine and swap it into the old 78 DL wagon I have here.  That would be a fun project, but there isn't really enough room up front for an EJ251.  Wonder what would fit...


Edited by davidsain, 04 November 2013 - 09:36 PM.


#12 presslab

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Posted 04 November 2013 - 09:53 PM

I assume the oil level was good? Could there have been ATF in the gear oil? That seal between the two can fail sometimes. I think it's usually the pinion bearing that lets go first, which if not caught right away will wipe out the R&P.

#13 Gloyale

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Posted 05 November 2013 - 11:53 AM

I

 

R&R requires removal of the transmission and removing this Torque Converter Clutch Case from the front of it.  This does NOT require disassembly of the transmission as another poster suggested unless one wishes to call this case removal "disassembly of the transmission".  As long as the pinion shaft seal between the diff and the transmission has not been compromised, it's doubtful there is any damage to the innards of the transmission.  

 

You absolutely do have to disassemble the trans, at least partially to replace the Ring and pinion, and the pinion gear...(which is the part that fails and causes the noise/grinding)

 

In addition to the front diff section (TC case), you also need to remove the transfer section at the back to access the pinion shaft nut.  And also the Oil pump section (sandwhiched between diff and trans body).  The pinion shaft seal is set into the pump......and If the bearing went out.....that seal is wiped (it's actually 2 twin seals set in back to back)

 

All in all it's about $850 in parts (R&P gears, Pinion Bearing, Pinion seals, Tube seal, Oil Pump body metal gasket, and transfer flange gasket, fluid and filtter, at a minimum) + labor about 13 hours.



#14 soobyhobby

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Posted 25 January 2014 - 12:57 PM

I have two auto trans from 2000 Outback. 1 has front diff failure and 1 has trans failure(long delay into gear and doesnt shift right). Can I remove the front diff from the trans with a good diff and put it on the trans with the blown diff? Is this a very big job? Any info is much appreciated!



#15 CNY_Dave

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Posted 25 January 2014 - 07:28 PM

As I understand it, you pull everything off the front, and the tail shaft and MPT, so the valve body doesn't get disassembled and the internal spinny bits except for the front drive shaft stay in place.

 

I went the used-trans route as you can get one knowing the mileage, and doing the R&R myself it was affordable.

 

I plan on keeping the car long enough it would have been worth $1500 having the one in there repaired, but finances didn't allow.



#16 roadsubiedog

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Posted 27 January 2014 - 02:35 PM

my 99 outback 5 speed is making a whining/squealing noise at low speeds. the squealing happens at acceleration and deceleration and it only happens in gear. when I push in clutch pedal and put it in neutral there is no noise.

 

one mechanic suggested it could be wheel bearings or the drive shaft. if that was true wouldn't it make noise even with clutch disengaged or rolling in neutral?



#17 CNY_Dave

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Posted 27 January 2014 - 08:49 PM

A squeal is less likely to be an axle or diff.

More whine, or more squeal?



#18 roadsubiedog

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Posted 27 January 2014 - 10:20 PM

the whine is a low sound and the whine comes and go at low speeds. just cant pinpoint it. have taken it to 2 shops and both times there was very little noise. one guy said it sounds like something needs lubricant. btw , I cant notice any sound at hwy speeds. buts its very noticeable at low speeds after the car has been sitting overnight. the more I drive  the less noise, but the low whine is always there but very slight.

 

when I first bought the car 9 years ago I took it to a quik lube for service and the guy told me that the Subaru did not have grease points so I have always done the oil changes myself every 3 k miles. I like it better that way anyway since I believe I can check everything better. thanks for your reply.



#19 CNY_Dave

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Posted 28 January 2014 - 08:55 AM

Have you checked the diff fluid levels?

 

Here is my bad front diff noise

 



#20 roadsubiedog

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Posted 28 January 2014 - 03:12 PM

the front one is perfect. in fact recent fluid change. I checked the rear one this past summer. it was perfect too. the noise seems to be near front or maybe under the seats. wow. that noise in the video sounds sick. nowhere near my sound though.



#21 Gloyale

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Posted 28 January 2014 - 09:09 PM

my 99 outback 5 speed is making a whining/squealing noise at low speeds. the squealing happens at acceleration and deceleration and it only happens in gear. when I push in clutch pedal and put it in neutral there is no noise.

 

one mechanic suggested it could be wheel bearings or the drive shaft. if that was true wouldn't it make noise even with clutch disengaged or rolling in neutral?

 

Possibly a "chirping" kind of squeal?  Does it do it in Neutral sitting still?

 

COuld be a chirping Throw Out Bearing.



#22 roadsubiedog

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Posted 28 January 2014 - 10:36 PM

5 speed. no noise in neutral. noise stops when clutch pedal pushed in between shifts. also if I put in neutral while going down the road , it rides very quiet. I wish I could post a video. that's a great idea.



#23 1-3-2-4

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Posted 28 January 2014 - 10:52 PM


Ouch!

Well I experienced the same issues with my 2001 H6 VDC, with almost exactly the same problems. The whine got louder and louder, and then I started noticing it on deceleration too.

I did end up replacing the entire transmission before it "exploded" though ... we had it up on a lift and you could see the whole unit vibrating really badly. That was my warning ...

Hang in there!

 

 

My '03 forester XS lost it's front Diff this way, the crazy thing happened was I was already about 5 miles on the road when the wine started.. so I pulled off the exit nearest the dealer I was going too, I went about 1,000 Ft and just as I was leaving from a stop light with the lightest amount of throttle the front diff exploded.. I have the pictures around someplace.

 

Long story short the front diff case on the 4EAT cracked and the driveshaft popped out a little.






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