South Bend clutch slipping after 16k miles

[millere5815]

I thought I noticed something off with my car the other day when passing someone on my way home from work. Tonight I decided to replicate it. Put my car in 5th gear at 60 MPH, sits at around 1800 RPM. Put my foot down as if I was passing someone, and the RPM shot up to 2200 RPM, the dropped down slightly. I can only guess that is my clutch, which really pisses me off since I just had it installed around 16k miles ago.

Does this sound like a clutch problem to you guys? If not, what could it be?

Update: The clutch was not the problem. The slave cylinder was not working properly, causing the clutch to slip.

Update, again. 1/26/16 : got my car back about a week before. New slave and master cylinder, as well as having the clutch cleaned up by south bend. The clutch is still slipping, and getting worse.

 

[mk1-83]

yes cluch, don't let it slipping to much. it makes the flywheel bad with hot spots.

replace it with a sachs tdi cluch it holds 450nm.
when install see how flywheel is and brush the surface a bit.
then install cluch and drive normal for 500 km city driving is best then you can abuse it

 

[PGM jetta]

Yep it's the clutch. Probably because of your .658 5th gear. Your clutch is rated for 325 ft-lbs and you are making nearly 300ft-lbs.

Just start downshifting to 4th when you hammer on it.

I have the DC stage 2 clutch from Boraparts. It's rated for 427ft-lbs

Sent from my XT1254 using Tapatalk

 

[BuzzKen]

Southbend stage 2 daily will not hold your mods. dlc1019's with an 11mm make awesome power.

 

[panthers89fan90]

.

Yep it's the clutch. Probably because of your .658 5th gear. Your clutch is rated for 325 ft-lbs and you are making nearly 300ft-lbs.

Just start downshifting to 4th when you hammer on it.

I have the DC stage 2 clutch from Boraparts. It's rated for 427ft-lbs

Sent from my XT1254 using Tapatalk

That 427ft-lbs is at the crank...

He is making close to 300ft-lbs at the wheels...

Two different outputs...

I like comparing power on an equal level. So, you'd ideally want the torque figure for his car and the torque figure for the clutch in both whp.

 

[PGM jetta]

That 427ft-lbs is at the crank...

He is making close to 300ft-lbs at the wheels...

Two different outputs...

I like comparing power on an equal level. So, you'd ideally want the torque figure for his car and the torque figure for the clutch in both whp.

Is the south bend numbers at the crank or at the wheels then? If at the crank, then he's far beyond it's rated limit.

Also, are you sure his posted numbers at the wheels? Everyone is different so I agree we need to be on the same page on whether we're discussing crank or wheel torque

Sent from my XT1254 using Tapatalk

 

[mountain lion]

Those numbers are in line for wheel horsepower with those mods.

NOT a good idea to be power stomping 5th gear with a .658 in it, especially in lower rpms. You'll eventually do damage to the transmission this way with the taller gear and higher power output - it puts a lot of stress on the splines and stuff...major repairs when something breaks. Take it easy in 5th, slam away in any other gear.

Back to slipping, what happens in 3rd and 4th?

 

[millere5815]

Thanks for the replys.

South bend clutches are rated for torque at the wheels. So it was rated 330 ft/lb torque at the wheels. I know that isn't a huge difference, but at the time, I had no idea my car was going to put out that much torque.

I have had it slip as I stated above in 5th, and just a little bit in 4th. It only slips about 1000 rpm in forth, if it all. 3rd gear seems fine.

 

[Lug_Nut]

Ummm... rating a clutch by "power" (torque multiplied by RPM) is just silly. The same holding force limit of say 300 lb*ft could be 300 HP at 5252rpm, or 600 HP in some formula1 10,500 rpm, or just 100 hp at 1750 rpm. So using "power" is nonsense.

Similarly the torque multiplication factor of the transmission makes "wheel torque" or "wheel power" just as nonsensical. 300 lb*ft at the wheel could be just 100 lb*ft at the clutch with a 3:1 gear ratio (1:1 gear and 3:1 final drive), or it can also be 30 lb*ft at the clutch (3.3:1 gear and 3:1 final).

There's a reason clutches are rated by torque and rated at the clutch.

 

[millere5815]

Ummm... rating a clutch by "power" (torque multiplied by RPM) is just silly. The same holding force limit of say 300 lb*ft could be 300 HP at 5252rpm, or 600 HP in some formula1 10,500 rpm, or just 100 hp at 1750 rpm. So using "power" is nonsense.

Similarly the torque multiplication factor of the transmission makes "wheel torque" or "wheel power" just as nonsensical. 300 lb*ft at the wheel could be just 100 lb*ft at the clutch with a 3:1 gear ratio (1:1 gear and 3:1 final drive), or it can also be 30 lb*ft at the clutch (3.3:1 gear and 3:1 final).

There's a reason clutches are rated by torque and rated at the clutch.

I thought everyone on here so far has been talking about torque?

 

[TheHolyCobra]

The funny part is everyone is talking about torque and horsepower figures and what the clutch can handle. But millere has not referenced if he followed the clutch break in period specified by SouthBend. He's under the rated horsepower and torque rating for the clutch, so then why is he slipping?

Lots of people overlook when SB, or any clutch manufacturer, tells owners to put XXXX miles of normal city driving on their clutch before they go wide open throttle. SouthBend recommends 1000 miles if i remember correctly.

It is very easy to glaze over a clutch disc by not following this rule. When the two surfaces don't fully break in and seat together, you get issues with clutch slip. No matter the car or the power level...ask me how I know

 

[mk1-83]

yep when i installed mine sachs stock tdi clucth, it was not holding torq good (450nm)

after some normal driving it holds fine this wash with 11mm race520 gt1752vb 210chp/450nm.

looks like the plate and pressure plate must bend in with the surface.

 

[Mike_D]

I have been installing south bend clutches for about 12-13 years and I am surprised yours is slipping. In my experience south bend clutches have held significantly more than what they are rated at. I have never seen one slip under what it was rated for. This is with light duty pickups though.

 

[john.jackson9213]

I have a stock VR6 clutch in my car for the last year. In August, I put a new turbo on the car that boosted the torque up to 313 lb/ft on the dyno. I noticed some hints of slippage at peak torque in top gear. After retuning the ecu for low smoke, the torque was down to 285 lb/ft and I have not has any clutch slipping since. So I think you are at the torque limit for your SB2 Daily clutch. The SB 2 Endurance is supposed to be rated at 350 lb/ft. You may want to adjust your tune for less peak torque in the interest of clutch life. Then save for stronger clutch.

 

[dogdots]

My SB Stage 2 Endurance has held my power without slipping for over 230k miles in my hot rod Jetta. I currently have one of my B5.5 TDI clutches there getting relined with Stage 2 E material, as the Euro Valeo B5 TDI clutch started slipping after 13k miles. My Jetta has an aggressive tune, 11mm pump, 764's, 17/22,3 bar, etc and I drive it hard. My B5.5 that started slipping only has Malone stage 2, otherwise stock.

 

[john.jackson9213]

Is the south bend numbers at the crank or at the wheels then? If at the crank, then he's far beyond it's rated limit.

Also, are you sure his posted numbers at the wheels? Everyone is different so I agree we need to be on the same page on whether we're discussing crank or wheel torque

Sent from my XT1254 using Tapatalk

Consumer dyno numbers are typically at the wheels. Otherwise you have to supply some "mythical correction/fudge factor" that is of no use when comparing one dyno to another dyno. It just becomes a game of "my fudge factor is bigger than your fudge factor".

 

[Franko6]

It's a simple math problem. Not enough dollars for big enough clutch.

I have customers that say "I'd rather cry once then cry twice." Meaning, getting a clutch a bit too large is much better than getting a clutch a tad small.

 

[millere5815]

I did follow proper break in procedures when I got my new clutch. I waited over 1,500 miles before I even slightly got on it, because most of my driving is highway miles.

When I got the transmission and clutch put in, I wasn't sure how much power I was putting down yet. I told the person who is putting it in all of my mods and said I'll need a clutch that can handle that power. I had no idea I was going to put be putting out anywhere near 300 foot pounds of torque

 

[TheHolyCobra]

I did follow proper break in procedures when I got my new clutch. I waited over 1,500 miles before I even slightly got on it, because most of my driving is highway miles.

1,500 miles of highway driving does not equal 1,500 miles of stop and go miles. A clutch and flywheel surface don't wear or break in if you stick the car in 5th gear and cruise the highway.

I'm sorry you're having your troubles OP. Unless there is some other factor that hasn't been discussed yet, it sounds like you got a faulty unit or you didn't break it in sufficiently.

 

[millere5815]

1,500 miles of highway driving does not equal 1,500 miles of stop and go miles. A clutch and flywheel surface don't wear or break in if you stick the car in 5th gear and cruise the highway.
I'm sorry you're having your troubles OP. Unless there is some other factor that hasn't been discussed yet, it sounds like you got a faulty unit or you didn't break it in sufficiently.

I checked my fuel logs. It was about 1200 miles of my normal commute. my commute is; 9 miles to the next town over. 3 miles though town, with stoplights, another 7 miles in the country at 55mph, then 6 miles of back roads, with 5 stop signs, until I get to work, which has 2 stops in town. That't my daily M-F drive, one way. If that won't break in the clutch correctly, I will never be able to do so.

 

[KERMA]

Unless there is some other factor that hasn't been discussed yet,

There is one other thing to consider: Nobody likes to ever admit this, but a "determined" driver can smoke *any* clutch. In fact, the factory VW new car warranty specifically excludes the clutch for this very reason. Just throwing that out there.

Not saying that's what happened here, but it needs to be part of any discussion of clutch "problems"

Always keep in mind, for every one complaint that gets posted on fred's, there are literally a thousand other South Bend Clutches in service for hundreds of thousands of miles per car with extremely happy owners.

 

[millere5815]

There is one other thing to consider: Nobody likes to ever admit this, but a "determined" driver can smoke *any* clutch. In fact, the factory VW new car warranty specifically excludes the clutch for this very reason. Just throwing that out there.

Not saying that's what happened here, but it needs to be part of any discussion of clutch "problems"

Always keep in mind, for every one complaint that gets posted on fred's, there are literally a thousand other South Bend Clutches in service for hundreds of thousands of miles per car with extremely happy owners.

That is true. This wasn't a post to bash Southbend. Almost no one goes on the forum to talk about something working well, because we are out enjoying whatever it is we got.
In the many cars and motorcycles i've owned, I've never had a clutch go out. That's why I asked if it was my clutch or something else I was missing. I am in no way here to make it sound like southbend is junk, because I know they make thousands of these for cars and trucks alike.

That being said, I am not one of those people who would perposfully break my only vehical to make a company look bad. That gains me nothing. I need to work, and I need my car to get there. I believe that something about the one in my car is faulty. It happens to every product that anyone could buy.

 

[cevans]

If the pressure plate wasn't fully torqued down flush to the flywheel it will lower the holding capacity of the clutch. That being said you are pushing the limits of the daily with your setup even properly installed. My rule of thumb is that you can do a turbo or nozzles with the daily, if you do both you'll need to upgrade to the endurance feramic type.

 

[millere5815]

If the pressure plate wasn't fully torqued down flush to the flywheel it will lower the holding capacity of the clutch. That being said you are pushing the limits of the daily with your setup even properly installed. My rule of thumb is that you can do a turbo or nozzles with the daily, if you do both you'll need to upgrade to the endurance feramic type.

Thanks for the recommendation. I'm going to be dropping it off at the guy who installed it all. He wants to tear it all apart to see what might be failing.

 

[john.jackson9213]

The clutch is one place I don't like to cheap out on. Simply because it cost so much to replace. My old SB stage 2 Endurance was great for 60K miles. Then the circumferal retaining spring broke. Freak incident. Had to replace it with a locally sourced VR6 clutch simply because I could not get a replacement in less than 5 days and had a trip planned in 2 days. While my VR6 clutch is holding up fine right now, I have set aside funds to replace the clutch with at least another SB 2 Endurance in the next 6 months. May be looking at a DC clutch disk for the replacement. BTW, the old SB2 Endurance clutch disk looked great at 60k miles but my engine then maxed out at 245 lb/ft torque at the wheels.

 

[Lug_Nut]

I thought everyone on here so far has been talking about torque?

Apparently you missed a few, including your own...


post #5

I like comparing power on an equal level. So, you'd ideally want the torque figure for his car and the torque figure for the clutch in both whp.

post#7

Those numbers are in line for wheel horsepower with those mods.

"Those numbers" referencing PGM's question of South Bend rating at the clutch or at the wheels.


post#8

South bend clutches are rated for power at the wheels.

 

[millere5815]

Apparently you missed a few, including your own...
post #5
post#7
post#8

Fair enough. I put power, but meant torque. I'll fix it.

 

[panthers89fan90]

So... the stage 2 daily holds 325 ft-lbs of torque and the endurance holds 350? I would have thought there would have been a bigger gap in holding force than 25 ft-lbs?

 

[[486]]

If the pressure plate wasn't fully torqued down flush to the flywheel it will lower the holding capacity of the clutch.

if it was that loose it'd be rubbing on the pinion bulge in the bellhousing

 

[Ol'Rattler]

There is one other thing to consider: Nobody likes to ever admit this, but a "determined" driver can smoke *any* clutch. In fact, the factory VW new car warranty specifically excludes the clutch for this very reason. Just throwing that out there.

Not saying that's what happened here, but it needs to be part of any discussion of clutch "problems"

That's so true. A kid posted here that he bought a brand new car but didn't know how to drive a stick and completely smoked the clutch by the time he got home.

The point is not everyone knows how to drive a clutch. A clutch likes to be either completely engaged or completely disengaged and the longer you linger between the two, the faster a clutch wears.

Just something to consider. My DC stage 1 has 107K miles on it and has no sign of slipping and it only is rated at 357 foot pounds of torque.

Let us know what your mechanic finds out when he takes it apart.