Replace rear main seal, with clutch? (Part quality issue.)

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I need to have the clutch on my 2006 Mazda 3 replaced (I've got 177k miles on the car, with the original clutch). I know people always say you should do the rear main seal, while the transmission is out.

But I was talking to a well recommended local transmission shop, the guy seemed really straightforward, and he said if my rear main seal is not leaking, he would not replace it, because the new parts he can get for that on my car are low quality these days. He said you just can't get a rear main seal now that's the quality of the original one.

I know from reading these forums that other things, like CV axels, have no good replacement parts anymore and people recommending rebooting the originall CV joints and keep the axel as long as possible. So the transmissions shop's comment about rear main seal part quality seemed plausible to me. What do people think? Should I follow the advice not to replace the rear main seal if it's not leaking?
 
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We did clutches left and right on Subarus for wear and tear and when we just had the engines out for a head gasket job. We never did a rear main seal that I know of, and this was a Subaru dealer where an engine or 3 was out every day of the week.

I agree that if he only has a line on aftermarket parts, you’re better off leaving it alone. If he’s ok with oem parts, I guess it’s up to you. But then you introduce mechanic error, hope he doesn’t scratch the crank when removing it etc.
 
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You have to remove the flywheel to get to the seal so that's more labor and might need new bolts as well. At 177K, if it ain't leaking, I'd leave it. If it was at 277K, I'd say otherwise. Hopefully it doesn't starting leaking a thousand miles later, just because you asked about it. :*******:
 

cb474

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We did clutches left and right on Subarus for wear and tear and when we just had the engines out for a head gasket job. We never did a rear main seal that I know of, and this was a Subaru dealer where an engine or 3 was out every day of the week.

I agree that if he only has a line on aftermarket parts, you’re better off leaving it alone. If he’s ok with oem parts, I guess it’s up to you. But then you introduce mechanic error, hope he doesn’t scratch the crank when removing it etc.
He was okay with me bringing in the clutch kit myself if I want to, so I assume he'd be okay with me getting the rear main seal from Mazda. I hadn't considered that there would be much risk of mechanic error. Is it a tricky job? I guess I could wait and if he says it's leaking, then get the part from Mazda. I can deal with the car being in the shop an extra day if I have to.

You have to remove the flywheel to get to the seal so that's more labor and might need new bolts as well. At 177K, if it ain't leaking, I'd leave it. If it was at 277K, I'd say otherwise. Hopefully it doesn't starting leaking a thousand miles later, just because you asked about it. :*******:
I think the flywheel is coming out anyway, at least to be resurfaced and maybe replaced. Although, I was thinking of just having him replace it anyway, since I can get a LUK flywheel for $73.
 
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... I hadn't considered that there would be much risk of mechanic error. Is it a tricky job? ....

If he's a capable mechanic, it's a safe, quick, and simple job if the flywheel is out. Minutes. An amateur can mess it up, certainly.

I went through this decision on one of my vehicles when I was rebuilding the AT a few years ago, ~160k miles IIRC. I went ahead and did it and am glad I did. With motorcycles and some critical places, I follow the "if it ain't leaking, don't touch it" idea. But when it's so very, very hard to get to and the vehicle already has serious miles and years on it - it makes sense to do it.
 
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He was okay with me bringing in the clutch kit myself if I want to, so I assume he'd be okay with me getting the rear main seal from Mazda. I hadn't considered that there would be much risk of mechanic error. Is it a tricky job? I guess I could wait and if he says it's leaking, then get the part from Mazda. I can deal with the car being in the shop an extra day if I have to.


I think the flywheel is coming out anyway, at least to be resurfaced and maybe replaced. Although, I was thinking of just having him replace it anyway, since I can get a LUK flywheel for $73.
It’s not really a hard job, a mechanic should be happy to do it while in there for the clutch. It’s just that I’m a mechanic, so I’ve seen SO many hacks in the few shops I’ve worked it it’s hard to trust anyone. Seals of any kind I have seen screwed up quite often.
 

cb474

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It’s not really a hard job, a mechanic should be happy to do it while in there for the clutch. It’s just that I’m a mechanic, so I’ve seen SO many hacks in the few shops I’ve worked it it’s hard to trust anyone. Seals of any kind I have seen screwed up quite often.
Yeah, I feel like I've tried every local mechanic near me and never been that impressed, even with people with amazing reviews (though mostly I was underwhelmed because they want to do work that I know is unncessary or charge me $100 for a $10 part and its a part that's crap quality). But, for what it's worth, this transmission shop comes well recommended, online reviews seem to be very good, and I figure since they are a transmission shop, they must do rear main seal jobs a lot. And when I talked to the guy at the shop, I appreciated that he was honest about the difficulty of finding good parts and not just pushing the rear main seal.
 
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I think the flywheel is coming out anyway, at least to be resurfaced and maybe replaced. Although, I was thinking of just having him replace it anyway, since I can get a LUK flywheel for $73.
Unless it has cracks in the surface, I don't think I would bother. Just go over it with a brake rotor disc to clean it up.

65Flywheel.JPG
 
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I would replace the seal with the transmission being removed.. I would believe a quality aftermarket seal being properly installed would be a far better gamble than the original (probably hardened) 16 year old OEM seal with 177k miles on it.

I think your mechanic wants to avoid a possible warranty issue with a new seal if it were to leak..
 
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D60

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I haven't seen the exact design here but typically I worry that it's driven perfectly square. It can (and almost surely will) start out slightly cocked but when you're done you want it set at exactly the same depth all around the diameter.

Some seals seat up against a metal lip so that's easy enough -- go until it doesn't go. But some have some float and this is where the proper seal driver is arguably mandatory to seat it at the proper depth all the way around.

Granted, I'm oddly paranoid about such things and have regularly machined custom discs and drivers to make it idiot-proof (in which case I'm almost not able to screw it up!)

Also, if the seal is not obscenely expensive from Mazda I'd order TWO. Just in case. Seriously. Nothing worse than having the job stall while you wait for YET ANOTHER special order. Or if your Mazda dealer has several sitting on the shelf, you're golden.
 
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If you decide to change the seal I highly recommend you replace it with a seal from the dealer. Aftermarket anything can be of questionable quality.
 
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Replace ONLY with Mazda OE if it’s leaking but I’m inclined to say if the flywheel needs to be pulled, might as well. Labor isn’t cheap.
 
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Don't touch it. I have NEVER seen a rear main leak on any Mazda engine, nor do I ever replace rear mains when doing a job that requires trans removal. Disturbing a perfectly installed OEM seal to hopefully install another seal "just because" is a fools errand.
I have seen so many guys pry out the old ones with a flathead screwdriver and leave gouges, then install new ones crooked.
 

cb474

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Well, I have to say, it seems like half the people here think it's a good idea to replace the seal and half don't. And everyone makes pretty good arguments. So I'm a bit confused. Also, I talked to two well recommended transmission shops. One said, if it's not leaking not to replace it, but mainly because aftermarket parts are low quality. The second said, it's easy to do, he always recommends doing it, after more than 100k miles it's probably starting to dry out, he can get the part from Mazda, and he's never had one come back leaking. The only consensus in this thread seems to be to use the Mazda seal, if it's replaced.

Regarding the flywhell, the two transmission shops I talked to also both said they would pull the flywheel to resurface it, in which case I'm thinking maybe I should just buy the Luk flywheel for $72, which is cheaper than what they're charging for resurfacing.
 
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