Leaking Rear Main Seal - Can it cause clutch to slip?

[RockJGC]

I'm thinking a leaking rear main seal can cause the clutch to slip, but I'm not sure. I'm trying to picture in my head how the clutch sits in proximity to the rear main seal and I'm not sure if a typical leaking rear main seal will get oil on the surface of the clutch or not.

[apeck240]

Look at a picture of our stupid flywheel design, no it can't. Trans input shaft leak can go right in though, through the collar the release bearing rides on, right into the pressure plate

[Theiceman]

pic is worth a thousand words..

RMS flange


then the flywheel bolts to that :


than that bolts to the flex plate :


that is attached to another module behind that that contains the clutch.

bonus content.. for those who wondered why you have to remove the engine to replace the pistons, in the first pic you can see how the RMS flange is bolted to the upper oil pan. stopping it from being detached to remove the pan. If a shop proposes to do it without removing the engine, i would wonder.

[RockJGC]

Okay.....so I have a problem. Last year, my original dual-mass flywheel failed (broken springs), so I pulled the transmission, and swapped in a SouthBend Stage II daily clutch kit, which came with a brand new dual-mass flywheel. Of course I also installed the new revision rear main seal since I was in there. Everything worked as expected and I was a happy camper. Then I decided have the car APR tuned (Stage 1) and everything seemed fine for about a month or so. Then the clutch started slipping under load in 5th & 6th gear.

So please tell me that a Southbend Stage II Daily clutch kit isn't too weak for an APR Stage 1 car. Is that even possible?

[MongoMcG]

Okay.....so I have a problem. Last year, my original dual-mass flywheel failed (broken springs), so I pulled the transmission, and swapped in a SouthBend Stage II daily clutch kit, which came with a brand new dual-mass flywheel. Of course I also installed the new revision rear main seal since I was in there. Everything worked as expected and I was a happy camper. Then I decided have the car APR tuned (Stage 1) and everything seemed fine for about a month or so. Then the clutch started slipping under load in 5th & 6th gear.

So please tell me that a South Bend Stage II Daily clutch kit isn't too weak for an APR Stage 1 car. Is that even possible?

The South Bend Stage II daily is rated to 375 ft lb of torque.
APR advertises their stage 1 E85 tune torque spec at 388 ft lb at around 5400 RPM.
So, yes, slippage is possible if you're using E85.

The torque from APR Stage 1 tunes for 91, 93 and 100 octane are 329, 338 and 360 ft lb, respectively.

[Theiceman]

its funny .. when you said slipping clutch , i was going to ask .. is it a southbend ?

i hear nothing but problems with that thing on this forum , you might want to do a search.

[jbain2]

I’ve run multiple southbend clutches. From my Mk IV, to my B5 S4. I ran a stage 2 daily on my K04 B5 S4. Held the power just fine. Never had a single issue.


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[RockJGC]

The South Bend Stage II daily is rated to 375 ft lb of torque.
APR advertises their stage 1 E85 tune torque spec at 388 ft lb at around 5400 RPM.
So, yes, slippage is possible if you're using E85.

The torque from APR Stage 1 tunes for 91, 93 and 100 octane are 329, 338 and 360 ft lb, respectively.

No E85 for my plastic intake engine. But yeah, I've run both 91 and 93 octane and it slips on both.

Pisses me off that I gotta do another clutch so soon. So what's a better option than Southbend? I want to keep my dual-mass flywheel and I don't want anything that's going to wear out my left leg in traffic, so I want to keep pedal pressure on the light side.

[apeck240]

No E85 for my plastic intake engine. But yeah, I've run both 91 and 93 octane and it slips on both.

Pisses me off that I gotta do another clutch so soon. So what's a better option than Southbend? I want to keep my dual-mass flywheel and I don't want anything that's going to wear out my left leg in traffic, so I want to keep pedal pressure on the light side.

My spec stage 3+ holds probably double that power and the pedal feels stock

[MongoMcG]

It'll be worth some research for other possibilities. You paid for a clutch that is designed to handle what your car is giving it. Did they replace the input shaft seal with the clutch? Would suck if this came up for an 8 dollar part, but it's known to happen.

[Theiceman]

I’ve run multiple southbend clutches. From my Mk IV, to my B5 S4. I ran a stage 2 daily on my K04 B5 S4. Held the power just fine. Never had a single issue.


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I'm not saying everyone has issues, but those who do, seem to be running southbend. I'm no expert , just what I see on here

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[A4B8 2.0tfsi]

Well Sachs Performance is a good system, but it's got to be something else going on with your clutch. Stock clutch worked for my Stage 2, for 3 years until I changed it and went with F23L.

[RockJGC]

It'll be worth some research for other possibilities. You paid for a clutch that is designed to handle what your car is giving it. Did they replace the input shaft seal with the clutch? Would suck if this came up for an 8 dollar part, but it's known to happen.

No, it wasn't replaced. I did the clutch replacement myself in my garage. Believe it or not, the car had 17,000 miles on it when I replaced the clutch, so I didn't even think about replacing the input shaft seal. Maybe that was a mistake....I guess I'll find out when I pull the transmission again.

Believe me, I was aggravated when my dual-mass flywheel shit the bed. I could literally hear the broken springs inside it when it failed.....and even with the extremely low mileage on the car, it was out of warranty since the car is a 2016. There's no way the flywheel should have failed that soon. It's not like I'm abusive to the car....and I've been driving manual transmissions for about 30 years now. The only other time I've had a clutch failure on any of my cars was my old 5.0 Mustang with a T5 back in the day and that was because I beat the ever-loving shit out of that car. I grenaded the clutch and destroyed 3rd gear all at the same time.

[RockJGC]

Well Sachs Performance is a good system, but it's got to be something else going on with your clutch. Stock clutch worked for my Stage 2, for 3 years until I changed it and went with F23L.

Yeah, I agree. Now you guys got me wondering if the input shaft seal is leaking. I agree that something weird is going on. When I do eventually pull it apart and it's something like the seal leaking, then I'll probably just get a new clutch disk and stick with the Southbend pressure plate. Or if everything is dry and there's nothing obvious, then maybe I'll go Sachs Performance clutch instead. How's the pedal pressure on those?

[Theiceman]

i've read pulling the transmission on these things is a bit of a pig. Let us know how it goes, not many try it and post here.

[RockJGC]

i've read pulling the transmission on these things is a bit of a pig. Let us know how it goes, not many try it and post here.

Yeah, it's a job. And I did it in my garage completely by myself...no help from anyone. I have a small mid-rise lift, so enough room to pull the transmission out, but I still had to work on my back the entire time.

[MongoMcG]

Yeah, it's a job. And I did it in my garage completely by myself...no help from anyone. I have a small mid-rise lift, so enough room to pull the transmission out, but I still had to work on my back the entire time.

Looks like you have the garage for it and the skills, since you did it once. I went through the procedure in the FSM and watched a couple of vid's - not for the faint of heart. I am curious: how well did the transmission jack handle the 6MT, esp. stability and safety? A new clutch is on my list, but haven't decided if I want to take it on myself.

Speaking of Mustang transmissions, I still have the original AODE (essentially a 4R70) trans in the SN95 Mustang (72K Miles). I was going to mash it until it broke and replace with a Tremec, but it refuses to break. Surprisingly strong transmission (516 ft lb) paired up with the 3.8L V6, from which I built a 4.2L stroker, supercharged, cammed, gasket match ported & polished, upgraded the intake to the high flowing Windstar (minivan!) intake, and more. Fast enough, and torque-y as heck, but def not a corner carver. If I am ever going to make competitive autocross times in the Mustang it needs a Cobra rear end for the IRS and the 3.73 gear. Gotta' finish this B8 build because it interrupted the Mustang project, which is completely stripped and hanging on the rotisserie since last spring waiting for a final media blast and POR-15 coating on the bottom. It should be quite somethin' when done again, especially if I can find a deal on that Cobra rear end.

[RockJGC]

Looks like you have the garage for it and the skills, since you did it once. I went through the procedure in the FSM and watched a couple of vid's - not for the faint of heart. I am curious: how well did the transmission jack handle the 6MT, esp. stability and safety? A new clutch is on my list, but haven't decided if I want to take it on myself.

Speaking of Mustang transmissions, I still have the original AODE (essentially a 4R70) trans in the SN95 Mustang (72K Miles). I was going to mash it until it broke and replace with a Tremec, but it refuses to break. Surprisingly strong transmission (516 ft lb) paired up with the 3.8L V6, from which I built a 4.2L stroker, supercharged, cammed, gasket match ported & polished, upgraded the intake to the high flowing Windstar (minivan!) intake, and more. Fast enough, and torque-y as heck, but def not a corner carver. If I am ever going to make competitive autocross times in the Mustang it needs a Cobra rear end for the IRS and the 3.73 gear. Gotta' finish this B8 build because it interrupted the Mustang project, which is completely stripped and hanging on the rotisserie since last spring waiting for a final media blast and POR-15 coating on the bottom. It should be quite somethin' when done again, especially if I can find a deal on that Cobra rear end.

It's really not that bad....it's just a lot of disassembly. Believe it or not, my transmission jack is a Harbor Freight low lift unit (800 lb rating) and it worked really well. The platform is adjustable in all four directions and the thing is solid as a rock. As you can see in the picture, I used two straps to hold it since I was doing the job myself. And once I had it on the jack, I never took it off. I just replaced the entire clutch with the transmission still on the jack.

FWIW, one of the main reasons that I decided to replace the clutch myself is because I don't like other people working on my vehicles. Ever. I used to work as a dealership technician back in the day, so I know that guys take shortcuts all the time. Some of them are total hacks. When I work on my vehicles, it's by the book. Every bolt is torqued to spec. Every stretch bolt is replaced. I purchased the factory specified lubes (I think there were three of them). Every step is done by the book. Maybe I'm a little anal, but that's okay...I know the job is done right. Kind of ironic that I'm already having an issue and if it's related to something as simple as an Input Shaft Seal, then that's my own stupid mistake and I'll have to do the entire job over again.

BTW, if you don't have any kind of lift, the job can be done on jackstands. But I'm not 100% sure if you can get the transmission out from under the car on jackstands unless they are pretty high. I think I remember reading somewhere that you need 18" of clearance or something like that to get the transmission out from under the car. If not, you can still do the clutch job with the transmission under the car, but that would be a major pain in the ass and I wouldn't recommend it.

As far as your Mustang, yeah....I've heard those are pretty tough transmissions. And as much as I'm a manual transmission guy, I think those new 10-speed automatics they are using now are a lot of fun My buddy has one and I've ripped on it a few times. It was a blast.

[MongoMcG]

I have a four post lift in my restoration garage a couple miles down the road, so I can do most of the disassembly up high and then drop it onto the jack - maybe even put the jack on a rolling steel table. I watched the Flink Films guy use the table and it makes sense. It'll be springtime before I think about it much more because that garage has other cars put up for winter storage.

I'm with you on other people touching my cars, and am also a bit obsessive about torque specs and new bolts - habit from my classic car work. When it's done, and it's right, and it runs like it - that's pretty satisfying. There are a few gigs I farm out. Still, after an experience with the '64 Sting Ray, I double and triple check the work. A very reputable tech in the classic car community working at a similarly reputable shop did a four wheel alignment but did not install the passenger rear knock-off wheel correctly. The spinner was held on by only a couple of threads, and the darn thing came off at 70MPH on the highway during the first drive. All are well, and the damage to the car was not too bad. The sparks were pretty amazing. Took a bit of driving, but I was able to maneuver to the shoulder and stop without further incident. The shop owner was totally a stand-up guy about it - covered everything - but the Vette has not been back since.

[LarryFisherman]

Not OP but I'm in a bit of a pickle. My clutch has started to shudder (not slip) in 1st gear and 2nd gear upon engagement, but only after the car has been driven for a while and warmed up. Based on research it seems like it could be one of:

Warped flywheel
Input shaft bearing or leaking shaft seal
Throwout bearing

Clutch and flywheel was replaced by previous owner ~35k miles ago, so I don't think it could be that the clutch or FW has been worn from use, but who knows how they were driving the car. On top of that, the car came with an extended warranty, and if it's option 2 then it would be covered, but that means I would need the dealer to diagnose. If I take it to the dealer and it's either of the other two then I'd be on the hook for diagnosis + potential repair at $$ dealer cost. If I take it to an indy shop and it's #2, then I would have to pay for the shop's diag then take it to the dealer for another diag + warranty repair. Otherwise if it's not the input shaft then I'd have the shop fix.

Potentially expensive problem so not sure what to do. Anyone have any thoughts on what the most likely culprit could be?

[RockJGC]

Just wondering.....can the input shaft seal be removed & replaced from the outside? In other words, no need to open up the transmission, right?

[apeck240]

Just wondering.....can the input shaft seal be removed & replaced from the outside? In other words, no need to open up the transmission, right?

Yes very easy once the clutch assy is out