2006 Legacy 2.5 Clutch Slippage

[golucky66]

Hi all,

Recently had a 2006 subie Legacy 2.5 non-turbo come into the shop with a noise coming from the transmission. We looked at it, found that there was an issue internally and suggested the lady put in a used transmission. While I was doing the transmission I also did the driver's side motor mount (it was leaking bad) and a new flywheel and clutch kit (Sachs). But after I put it together and the lady picked it up she got towed back into the shop ~2-3 weeks later with a completely smoked clutch >500 miles on that clutch. 

 

Now, under warranty, I put in another clutch kit and another new flywheel after inspecting the master cylinder and the line plus reservoir. Everything worked flawlessly on the hydraulic system side. After I completed the clutch (now the 2nd time) I took it for a test drive ~5-7 miles and smelt clutch bad. As well as when traveling ~40 mph and checking the clutch with the old clutch in, rev it to 5k and drop the clutch to see how fast the rpm's snap back, the clutch was slipping bad. Again.

 

Ok, ok, third time my manger (who ordered all the part from the beginning) called up the dealer, and asked which flywheel is supposed to go in this car. The parts guy said it was a single mass flywheel (which I had put in a dual mass because literally every listing my manger could find said it called for a dual mass). The parts guy from the dealership said the dual mass goes only in the turbo models... Hmm...ok

 

On to the install of the third time, I again do all the work, put on the SINGLE mass fly wheel and me and my manager looked over the clutch + pressure plate and decided to reuse them as there were no noticeable issues with them and the fact that that clutch had 5 miles on it (my previous test drive). I finished the clutch and took it for the same test drive. The clutch is still slipping, maybe 20% better then the 2nd time. 

 

My manager called up the dealer, ordered the factory clutch kit and I'm going to be putting that, along with the factory fly wheel in on Thursday 3/3/16.

 

TL;DR

 

Installed a new (used) transmission with a new dual mass fly wheel + clutch kit. Clutch still slipped

installed a new clutch kit and dual mass fly wheel a second time. Clutch still slipped.

Installed the factory single mass fly wheel and reused the clutch kit from second install (had ~5 miles on it). Clutch still slips.

Will be installing the same factory single mass fly wheel + the factory clutch kit on Thursday 3/3/16. Will the clutch suddenly not slip?

 

 

My question is. Why is the clutch slipping so much? There is no excess pressure being applied by the master cylinder and we have the correct fly wheel in there now. And as a note, my shop uses Sachs clutch kits for a long time and very very rarely have issues. 

So is the OEM clutch kit going to magically make this not slip? 

What else is there that could cause this issue? 

Anyone have any ideas just for me to look over on Thursday?

[forester2002s]

Long shot: Does the clutch-plate slide freely on the splined input-shaft?

If there are any burrs on that spline, that could cause a slipping clutch.

[golucky66]

I cleaned the shaft on the tranny well with whatever that sand paper is call (idk just really fine grit) as well as where the fly wheel sits on the engine side. Also when I assembled it the alignment tool pulled out with ease.

I believe that it does.

Edited March 1, 2016 by golucky66

[Fairtax4me]

Pump the clutch pedal a few times then release it, on the slave cylinder, crack the hydraulic line loose and see if a lot of fluid pushes out under pressure.

 

Did a clutch on a Hyundai a few years ago and had a similar issue, but the clutch didn't totally smoke itself. Found out the master cylinder vent port was plugged and holding pressure on the release fork. Replaced MC and SC and flushed the hydraulic line.

[golucky66]

Pump the clutch pedal a few times then release it, on the slave cylinder, crack the hydraulic line loose and see if a lot of fluid pushes out under pressure.

 

Did a clutch on a Hyundai a few years ago and had a similar issue, but the clutch didn't totally smoke itself. Found out the master cylinder vent port was plugged and holding pressure on the release fork. Replaced MC and SC and flushed the hydraulic line.

 

Thanks so much, I will look into this Thursday and post my findings!

[golucky66]

Just got home from work today. Finished reinstalling the new OEM dealer clutch kit (with the reused OEM dealer flywheel) and the clutch doesn't slip anymore. There was a noticeable difference in the spring tension in the clutch plate and the spring in the clutch itself were much bigger. 

 

So, if anyone is doing a clutch on this era transmissions, be very cautious about using an aftermarket clutch, wouldn't want to have to redo the clutch 4 times like me   

 

Just as a side note, my manager contacted the parts distributor and they are going to be contacting Sach and informing them of this issue in hope for a redesign. 

[Fairtax4me]

I've used a few aftermarket clutches, but haven't ever had one slip right out of the box.

 

I would think that somewhere in that year range there was a change in the design and the parts listing was assuming that the older design was still used.

Glad the new one works!