What's involved in replacing rear differential?

[Appygirl]

Hi All- OK my 07 Redline had a rear diff leak last year- seal replaced. Then rear end leak again in July, so had recall done. Since the recall a very obnoxious smell has been coming into the cabin whenever I accelerate the car. Been to the shop 3 times, and they have tried numerous things. GM/Saturn finally indicated to replace the rear differential. They already checked the turbo and turbo wastegate, plus checked for crack in the catalytic converter. They were able to reduce the smell somewhat by draining the rear diff again and adding rear diff fluid without the additive which recall called for as I have the LSD. While in the shop trying to determine where smell was coming from, they screwed up my front mudflaps (they replaced them), and they minor cracked my front passenger fender even after I told them how careful they had to be lifting it. They apologized profusely and offered to fix and repaint the fender. Since the crack is so minor and not visible, I indicated to leave it, and I would watch it. If it gets worse, I will have the fix done. I just hate having to repaint a new car, especially the yellow since it is hard to blend. After the crack issue, they have been lifting the car on the alignment lift since their alignment lift allows you to drive the car up on it. Their other types of lifts are not like that. They are frame point lifts- leading to the ability to crack the fenders, if they are not spot on the frame points.

I am concerened about what all has to be removed from my car to do the replacement of the rear diff, and if the car will need to be re-aligned after the work, as I have been told rear wheels will probably have to come off. In addition, are there other items that I need to be on the look out for? If car needs realigned, I believe there is a post somewhere out here that has the specs which I can give the dealership. My dealership has never replaced a rear diff, so that is worrying me as they have already shown their ineptitude on working on the Sky.

[GaryH]

Originally Posted by Appygirl

Hi All- OK my 07 Redline had a rear diff leak last year- seal replaced. Then rear end leak again in July, so had recall done. Since the recall a very obnoxious smell has been coming into the cabin whenever I accelerate the car. Been to the shop 3 times, and they have tried numerous things. GM/Saturn finally indicated to replace the rear differential. They already checked the turbo and turbo wastegate, plus checked for crack in the catalytic converter. They were able to reduce the smell somewhat by draining the rear diff again and adding rear diff fluid without the additive which recall called for as I have the LSD. While in the shop trying to determine where smell was coming from, they screwed up my front mudflaps (they replaced them), and they minor cracked my front passenger fender even after I told them how careful they had to be lifting it. They apologized profusely and offered to fix and repaint the fender. Since the crack is so minor and not visible, I indicated to leave it, and I would watch it. If it gets worse, I will have the fix done. I just hate having to repaint a new car, especially the yellow since it is hard to blend. After the crack issue, they have been lifting the car on the alignment lift since their alignment lift allows you to drive the car up on it. Their other types of lifts are not like that. They are frame point lifts- leading to the ability to crack the fenders, if they are not spot on the frame points.

I am concerened about what all has to be removed from my car to do the replacement of the rear diff, and if the car will need to be re-aligned after the work, as I have been told rear wheels will probably have to come off. In addition, are there other items that I need to be on the look out for? If car needs realigned, I believe there is a post somewhere out here that has the specs which I can give the dealership. My dealership has never replaced a rear diff, so that is worrying me as they have already shown their ineptitude on working on the Sky.

Hi Appygirl, I share your concern about your dealerships ability to work on your sky. My dealer broke both my front fenders. Like yours, it could not be seen but I was afraid the crack would get bigger. I went to another Saturn Store in a nearby town. Both dealerships are owned by the same person, but the service depts are worlds apart. The second dealership replaced my front fenders. The work was done by a body shop, not the dealership. I don't think the paint on the fenders match like the original. But, its hard to tell because none of the body panels on a silver pearl match to begin with. ChiliSky had some alignment problems. Maybe she can give you a heads up on the alignment.

[cerberus]

I'm pretty sure you shouldn't need an alignment after a diff replacement. Mine didn't, nor did a few others I directly know of. No one's ever mentioned that, and we've had plenty of units replaced.

[GaryH]

PM Seal9. He had his replaced at least once, maybe twice. He can probably tell you anything you need to know.

[ggccg]

Check your exhaust system after they are done.

When the differential is replaced, they need to drop the exhaust.

When they did mine, they managed to wring off a stud on the bottom end of the Catalytic Converter. Upon doing that, they decided to drop the exhaust from the exhaust manifold instead and managed to cross thread two of the studs on reinstallation. They didn't bother to fix the Catalytic Converter stud they broke.

I have an aftermarket header installed in place of the stock exhaust manifold, and since the stock manifold doesn't have a gasket between the manifold and the Catalytic Converter, they just threw away the REQUIRED gasket for the headers. Needless to say, there were huge exhaust leaks at both ends of the Cat. Of course, they denied that they did any of that and it cost me $200 for my private mechanic to fix their incompetence.

Never underestimate the idiocy of Saturn mechanics.

[Appygirl]

Thanks guys for the advice. I figured I would have to reiterate for them to align exhaust properly as I have the Magnaflow exhaust. I will also advise that they need to be careful with the fenders and rear fenders on lifting the car. I won't worry about alignment of the car in general unless I notice issues after the fact.

[MandiLu]

Hey Appygirl.
Steve started this thread after our recall was done. We had a problem with the exhaust making a noise when they put it back one.
Terrible Vibration after Recall - any help??

[Appygirl]

Thanks to all. Got my rear diff in this AM and had it installed already. Car seems stiffer. Not sure if it is my imagination or not. Exhaust was aligned nicely. No further damage done to my fenders. They were able to do the work on the alignment lift which they can drive onto. The obnoxious smell that was coming from the car is gone.

[RenoSky]

Hi-
What's the secret to getting your retailer to stop replacing seals and to go ahead and replace the differential? Nothing but trouble with mine. I replaced seals under warranty last Sept, did the recall work in April.... leaking again and making a horrible noise. Is there a GM tech bulletin or hidden recall that I can show them? Suggestions?

[seal9]

First you not need an alignment after the replacement. It should take about 4 hours. they do drop the exhaust pipe from the header all the way back then the fun starts. Its really very easy so your car should be fine. Yes GaryH I have had two replaced now. The one I have now has been very good I passed on the recall replacement of the seal and my Dealer agreed "don't fix it unless its broke"...Seal9

[SILVER ANNIV]

Since you seem to have a good handle on where things are: is there anyway that wiring for the gas gauge could've gotten pinched during the diff replacement? My gas gauge started acting up the day after the recall work was done in the spring. They recalibrated it, replaced the sending unit and did another calibration, but nothing fixes it. I was given an warranty extension for any parts related to that in case the engineers can come up with a fix, but it's still very irritating to know you have at least half a tank of gas while it's pointing at E and the light's on.
Any thoughts?
Lori

[seal9]

Yes it's possible that the wires were damaged. you should be able to get an ohm meter and check to see if you have a ground from striped wires the connectors are under the matt in the trunk, You will see the access panel. you also have an in-tank fuel pump there so make sure you have the right wires. The problem is most likely the wire bundle on top of the Diff just to the right, when they installed the diff if you pull on the wire bundle you could have pulled a connector free or pulled a wire out...Seal9

[Appygirl]

Originally Posted by RenoSky

Hi-
What's the secret to getting your retailer to stop replacing seals and to go ahead and replace the differential? Nothing but trouble with mine. I replaced seals under warranty last Sept, did the recall work in April.... leaking again and making a horrible noise. Is there a GM tech bulletin or hidden recall that I can show them? Suggestions?

I had to take my Sky in and leave it for a day while they tried numerous fixes all the while talking to Saturn tech hdqtrs. When nothing worked, they then put in a request to replace the diff. It had to be approved by Saturn hdqtrs, but they approved it in half a day, and I had the new one within 3 business days. I checked with several individuals on whether I would need the car realigned because of the replacement of the rear diff and was advised it should not be necessary. This is the first I have heard it would need re-aligned. I feel the car is driving fine and alignment does not appear to be off for me at all. I will watch it more closely on the drive home today. With it being central IL, we have lots of straight level roads around here.

[SaturnSkyDude]

I had the rear pinion seal replaced on my Redline the other day and was told I had to because of the recall. My car was not leaking and USED to drive perfectly straight down the road and now if I hold the wheel straight it veers to the left. I would have to agree you shouldn't need an alignment for this procedure but for some reason my alignment is off. I checked the tire pressure and so did they so everything is fine there. I have an appointment next week with service and will let you know what they find out.

[seal9]

If the Diff replacement went the way it should (the Mechanic knew how to do it) the re-alignment is not required, none of the rear alignment is touched but I do know of one mechanic that strip of the wheels, rotors and so on to do it...seal9

[SILVER ANNIV]

Originally Posted by seal9

Yes it's possible that the wires were damaged. you should be able to get an ohm meter and check to see if you have a ground from striped wires the connectors are under the matt in the trunk, You will see the access panel. you also have an in-tank fuel pump there so make sure you have the right wires. The problem is most likely the wire bundle on top of the Diff just to the right, when they installed the diff if you pull on the wire bundle you could have pulled a connector free or pulled a wire out...Seal9

Thanks! I'll ask them to check it out.
Lori