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I am hoping for some information on AWD components. I purchased a Subaru (which I love) last month, because my last car, a Dodge mini-van with AWD, died. The mini-van (114k miles) had been running fine, but got a flat tire in July. The garage put the wrong size tire on -- 215 55 16. The other 3 tires were size 215 65 16. After driving around for 10 days or so, the car began to vibrate badly, and made a rubbing sound. The Dodge dealership I went to (different place than the garage that changed the tire) told me that the rear differential was shot and the rear axle needed to be replaced. I had the rear axle replaced w/ a used one -- very expensive. A week later, the vibration returned w/ a strong burning oil smell. The gear oil from the front differential was black and full of soot. That is when the dealership went looking for the root problem & discovered that the car had one tire of a different size. The dealership recommended that it was not worth the expense to determine the extent of damage to the front differential. The insurance co. for the garage that replaced the tire says that that was not the cause of the damage. The dealership says otherwise. I need to argue w/ the insurance co. Any thoughts? Advice would be much appreciated! Thanks, in advance.

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First off, save all receipts for everything including the tire itself. Then I would in a Dodge owners manual... it would probably have a warning about just this somewhere in it. Or contact Dodge directly and see if they can provide something in print stating that what we all know. Don't mix and match sizes.

 

You should be able to recover this one, I don't know how much your total bill was, but if worse comes to worse paying an attorney $500 to recover $2000-3000 might actually be worth it as well.

 

Just my $0.02

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Get an official letter from somebody at Daimler-Chrysler concerning the AWD system and use of tires that all at matching in tread, width, height, etc. If you can, get them to send it straight to your insurance company as a certfied letter. Or, you can send it certified to Daimler-Chrysler.

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if the odd size tire caused the problem, then there will be a warning in the owners manual. there seem to be 2 questions: 1. did the odd size tire caused the damage? and 2. whose reponsibilty is to know of the potential damage, yours or the tire shop?

 

#1 is going to be a no brainer. #2 i couldn't tell you. but if you persist with the ins. co. you will have a shot, if you give up you will have none.

 

did the tire shop tell you it was an odd size tire? did they tell you that it didn't matter? did they sell you what they had instead of what you needed? do they stock the right size and just put on the wrong one??

 

the difference between 55% and 65% of 215 is more than 3/4" in radius.that's a big difference. what worries me: was 10 days long enough to cause the problem?

 

good luck.

john

 

 

I am hoping for some information on AWD components. I purchased a Subaru (which I love) last month, because my last car, a Dodge mini-van with AWD, died. The mini-van (114k miles) had been running fine, but got a flat tire in July. The garage put the wrong size tire on -- 215 55 16. The other 3 tires were size 215 65 16. After driving around for 10 days or so, the car began to vibrate badly, and made a rubbing sound. The Dodge dealership I went to (different place than the garage that changed the tire) told me that the rear differential was shot and the rear axle needed to be replaced. I had the rear axle replaced w/ a used one -- very expensive. A week later, the vibration returned w/ a strong burning oil smell. The gear oil from the front differential was black and full of soot. That is when the dealership went looking for the root problem & discovered that the car had one tire of a different size. The dealership recommended that it was not worth the expense to determine the extent of damage to the front differential. The insurance co. for the garage that replaced the tire says that that was not the cause of the damage. The dealership says otherwise. I need to argue w/ the insurance co. Any thoughts? Advice would be much appreciated! Thanks, in advance.

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Maybe a dumb question, but how can one wrong-size tire ruin the differentials at BOTH ends of the car? I can see it doing in the end where it is located, and being really bad for the center diff (if so equipped), but how can it destroy both ends?

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Good point. if you have uneven sized tires on one axle it just seems as though you're going around a corner to the differential. The only place I would expect damage after 10 days would be the center, because it has to deal with the speed difference between the front and rear. I don't know much about the dodge awd system though.

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There is a direct mechanical connection to the front diff

 

http://www.allpar.com/eek/awd.html

 

Just forward of the rear differential mounted between the driveshaft and the differential pinion is a unit with an overunning clutch and a dog clutch. When in any forward gear the dog clutch is disengaged. Whenever the front wheels are the same speed or slower than the rear wheels the over running clutch is slipping and no torque is supplied to the rear wheels. Whenever the front wheels are faster than the rear, as when they slip on ice or snow, the over running clutch locks up transferring torque to the rear axle, but only as much as the viscous coupling will supply. When the front axle is only slightly faster than the rear, only a small amount of torque is transferred. When in reverse the dog clutch engages which locks the driveshaft to the rear differential pinion because the over running clutch function is backwards for driving the van in reverse.

 

The AWD system does not split torque unevenly left to right. The left and right half shafts have a normal differential identical in function, if not truly identical, to the FWD differential. The driveshaft to the rear is turned by a ring and pinion driven directly from the ring gear (actually a helical gear) of the front axle differential. The ring gear drives the pinion, unlike normal ring and pinions where the pinion drives the ring. This whole ring gear assembly is hollow so that the a shaft from the front axle differential to the right side front axle half shaft can pass through the ring gear without affecting or being affected by power to the rear axle. There are no limited slip differentials in the transaxle.

 

 

The system got a little more sophistcated as it aged, but still basicallyt the same system, only with an electronic clutch replacing the dog clutch.

 

what a cheap rump roast system

 

nipper

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do not plan on the insurance company being "honest" or helping you. you will have to be persistent and on them all the time. what they say is not necessarily the truth. anything they say or promise, get it in writing. they will tell you one thing, but do something else. they will ask you to provide or do things but when you do they still don't do anything. they will string you along at first and act like there's nothing they can do without "proof". after a while if you're persistent they'll change tactics and act like they're doing something but really they're just dragging you along hoping you'll drop it and figuring that without an attorney you don't really mean business.

 

remember, they don't make money but handing out all the claims they can. without an attorney it is a long task but it is possible.

 

stay on them, call them all the time and don't back off.

 

have fun and good luck,

gary

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Nipper's explanation was pretty good, but I still don't see how one small tire can destroy the car. A small tire at the back would wear the rear diff, but stop the overrunning clutch from hooking up until the speed difference was even greater, as the average speed at the diff would be higher than at the front. A small tire on the front would feed more power to the rear, as it would look like the speed was always greater at the front. I can see this toasting the front diff, but why the rear one too? Unless the dog clutch hooks up when the back end runs fast? That might explain it.

 

I actually met the guy that was in charge of designing this system. A really nice guy, this was his last project before he retired. He was on "loan" from an Austrian company that was putting 4WD into every little econobox in Europe at the time. Everything from 10 HP mini farm tractors designed for farms in the Alps to Fiat's version of the Justy. I met him hiking. I hope I can still hike like that when I am 65. I was 1/3 his age, and had a hard time keeping up.

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Nipper's explanation was pretty good, but I still don't see how one small tire can destroy the car. A small tire at the back would wear the rear diff, but stop the overrunning clutch from hooking up until the speed difference was even greater, as the average speed at the diff would be higher than at the front. A small tire on the front would feed more power to the rear, as it would look like the speed was always greater at the front. I can see this toasting the front diff, but why the rear one too? Unless the dog clutch hooks up when the back end runs fast? That might explain it.

 

I actually met the guy that was in charge of designing this system. A really nice guy, this was his last project before he retired. He was on "loan" from an Austrian company that was putting 4WD into every little econobox in Europe at the time. Everything from 10 HP mini farm tractors designed for farms in the Alps to Fiat's version of the Justy. I met him hiking. I hope I can still hike like that when I am 65. I was 1/3 his age, and had a hard time keeping up.

 

from what i found on the web, those clutches were prone to failure, maybe thats why his front diff went bad too.

 

nipper

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I'm not a big fan of the wide varity of engineering solutions to the problem of putting power to all 4 wheels on dry pavement. Subaru has the only car based system that I put any faith in.

 

Dodge should have used a version of their Jeep based Select-trac sytem for the mini vans. By using a simple open center diff with a mechanical locker, you can have full time 4 wheel drive with the smoothness and durablity of open diffs and the option to lock the center when the going gets really slippery. Works great on our Grand Cherokee and you don't have to worry about mismatched tires sizes.

 

Perhaps they felt that any driver input was too much for minivan drivers though.

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[quote name=firstwagon

Perhaps they felt that any driver input was too much for minivan drivers though.[/quote]

 

thats exactly the reason why they did it that way "so that the inexpierienced driver can enjoy awd"

 

Actually Audi has a very good system also.

 

nipper

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thats exactly the reason why they did it that way "so that the inexpierienced driver can enjoy awd"

 

Actually Audi has a very good system also.

 

nipper

 

Audi's works really well but I know 2 Audi owners that have had very expensive AWD repairs. Makes Subaru parts look like a bargain.

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You might have good luck at small claims court. not sure of that limits in your state but in California it's $5000. No jury, don't necessarily need lawyers. Just get the info from the Dodge dealers head mechanic and have him sign it along with his credentials. Tire company can scream all they want that they didn't cause the damage, but the company who designed it should have more weight in terms of what caused the damage.

The argument that the owner should know is not the valid but it's more of a diversion. You went to a tire shop b/c you needed a service that they provide. You expect them to be experts in changing tires and doing it right. Like someone said, did they replace it without telling you that it was the wrong size? Even then they are the presumed experts in the field. It's like a tow truck towing an awd subaru by two wheels due to a parking issue or whatever. They would be liable for any damage caused by their actions.

with small claims court you don't have to incur the cost of litigation and if the insurance company get litigated, it will cost them more to fight it than to pay you.

 

Good luck and keep us posted.

 

BW

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Unfortunately the failure scenario that you describe can happen in these Chrysler minivans regardless of tire size differences. I know, because it happened to us, and I know we had a matched set of 4 tires. Turns out that as nipper says, the clutches in this design are prone to failure, especially in earlier model years of the AWD system. We had a 1994 plymouth grand voyager with this system, we had a clutch failure that resulted in full coupling to the rear wheels (as full as the viscous coupler would provide anyway), and we ended up with the vibration and burning oil smell that you described. When I took our van to the dealer, they saw the problem and after conferring with Chrysler they ended up eating the cost of completely replacing the rear end and the coupler. Our front diff was supposedly "fine," but IMHO the van never drove as smoothly as before the failure. Our failure happened at 64K miles, 14,000 past our drivetrain warranty, but I guess they didn't want the hassle of yet another dissatisfied customer so they didn't pass the repair cost on to us.

 

That's the nicest thing that an American car mfr. has ever done for me, and it was the last time that we were treated so well. Later on in the van's life all the paint began to flake off and we were eventually left with a vehicle that was 40% paint, 60% primer. Chrysler steadfastly refused to own up to the fact that they used a defective primer during those years, and although thousands of people tried to recover at least partial cost of repainting the vehicles, I don't know of any who were successful. We certainly were not.

 

I am suspicious of Chrysler to this day because of that episode, and despite their best attempts to get us to buy a new minivan in the ensuing years, I haven't ever given it a serious thought.

 

Good luck with your case. Although I can't believe that your tire caused your problem, it may have contributed to the final failure. I'm sure that Chrysler would rather provide you with an official warning statement about differing tire dimensions than own up to the fact that poor design and a catastrophic failure mode led to your situation!

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Thank you all so much for your input. It has been really helpful. When I brought the minivan to the service station to have the tire replaced, I gave them the punctured tire. They ordered the correct size, but Cooper sent the wrong (smaller) size. The owner realized it and re-ordered from Cooper, but the kid who replaced it accidentally put the wrong sized tire on. The gas station owner admits this much.

I have saved all of my receipts, and I think I can get a letter from the Dodge dealer who did the repairs saying that he believes it was the tire that caused all of the damage. I have also found some helpful articles on the Internet re the importance of matching tires w/ AWD cars. It also just seems like too much of a coincidence that within 3 weeks of having the tire replaced, I would need 3 repairs (ABS system, rear differential/axle, and front differential). I am probably headed for small claims court, but am willing to do that. Again, thank you all for your very informative responses!

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