High rpm clutch slippage
09-22-2007, 08:15 PM
#1
11 Second Club
Thread Starter
iTrader: (5)
Join Date: Mar 2006
Location: South Coffeyville, OK
Posts: 176
Likes: 0
Received 0 Likes
on
0 Posts
High rpm clutch slippage Im experiencing clutch slip at high rpm under wot (mainly 5K and up) which first impressions would say its a bad clutch. But, it only happens at high rpm. I can put it in 6th and dump the clutch and it wont slip. Or i can dump it at like say 3rd or 4th at say 20mph and say 4k rpm and it wont slip. Taking off from a stop it seems great but once i get to right around 5kish it will go straight to the rev limiter. Then shift to 2nd and it will be right back on the rev limiter. And when it does this, when i press the clutch pedal it feels stiffer and more springy for one pump then goes back to normal.
Within the last year ive replaced just about everything under there. about 8 months ago it was slipping also, but had completely different symptoms and it turned out the pressure plate bolts had loosened, so i loctite'd them. Back then, the pedal never felt funny and it slipped in all gears at any rpm under wot.
Today just for *****, i bled the system but to no avail. the fluid didnt look bad either. the line doesnt seem to be anywhere near the headers so i cant see it boiling the fluid.
Within the last year ive replaced just about everything under there. about 8 months ago it was slipping also, but had completely different symptoms and it turned out the pressure plate bolts had loosened, so i loctite'd them. Back then, the pedal never felt funny and it slipped in all gears at any rpm under wot.
Today just for *****, i bled the system but to no avail. the fluid didnt look bad either. the line doesnt seem to be anywhere near the headers so i cant see it boiling the fluid.
09-23-2007, 01:33 PM
#2
TECH Fanatic
iTrader: (31)
Join Date: Jun 2004
Location: Mesa, AZ
Posts: 1,284
Likes: 0
Received 0 Likes
on
0 Posts
The hydraulics only come into play when releasing pressure plate spring pressure. Other than that, it's up to the disk and pressure plate to make it all work. Yours aren't getting the job done for some reason--worn disk/plate or failed plate springs.
What you are feeling with the pedal are the effects of the excessive heat build-up while the clutch is slipping. Looks like time for a new clutch.
What you are feeling with the pedal are the effects of the excessive heat build-up while the clutch is slipping. Looks like time for a new clutch.
09-25-2007, 08:52 PM
#5
TECH Senior Member
iTrader: (23)
Join Date: Aug 2005
Location: Watertown, NY
Posts: 8,797
Likes: 0
Received 0 Likes
on
0 Posts
Worn out, warped, or glazed disc, pressure plate, flywheel is the most likely culprit, all of which will require a new clutch and a resurfaced flywheel.
Usually it will slip at all RPM's but im sure with time yours will slip down low too.
Usually it will slip at all RPM's but im sure with time yours will slip down low too.
09-26-2007, 11:07 AM
#7
11 Second Club
Thread Starter
iTrader: (5)
Join Date: Mar 2006
Location: South Coffeyville, OK
Posts: 176
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by matt3383
What clutch are you using? What power are you putting to the flywheel or to the wheels?
im puttin down probably 340-345ish rwhp. basically same mods as you but i run 13.2-13.0 and range from 107-109 mph
Trending Topics
09-26-2007, 12:04 PM
#8
TECH Apprentice
iTrader: (3)
Join Date: Sep 2006
Location: Arizona
Posts: 381
Likes: 0
Received 0 Likes
on
0 Posts
How long have you had the clutch installed? Mileage wise. See if you can get some specs on the clutch you have and what it is rated for torque wise. I had a similar issue with my clutch, i was overpowering it. I purchased a stock replacement clutch with better springs. The clutch i purchased was only rated for 350 ft/lbs at the flywheel. So we are both sitting around or above 400 ft/lbs at the flywheel. This could be causing your high RPM slipping.
What happened to mine is the car would shift normal at any rpm below 4.5k. Anything above it would slip. This happened for awhile till the disk wore down enough the the clutch would not engage again and the peddle stuck to the floor. Also another problem that caused the premature failure was my rear main seal was leaking. This caused the clutch disc to soften and wear down quicker. I only had about 8k miles on the clutch.
What happened to mine is the car would shift normal at any rpm below 4.5k. Anything above it would slip. This happened for awhile till the disk wore down enough the the clutch would not engage again and the peddle stuck to the floor. Also another problem that caused the premature failure was my rear main seal was leaking. This caused the clutch disc to soften and wear down quicker. I only had about 8k miles on the clutch.
09-26-2007, 01:12 PM
#9
11 Second Club
Thread Starter
iTrader: (5)
Join Date: Mar 2006
Location: South Coffeyville, OK
Posts: 176
Likes: 0
Received 0 Likes
on
0 Posts
the clutch has been installed for probably 12k miles or so. And my rear main does leak a bit since its got 120k+ miles on it. But ill look into finding more info out on that clutch.
09-26-2007, 01:26 PM
#10
TECH Apprentice
iTrader: (3)
Join Date: Sep 2006
Location: Arizona
Posts: 381
Likes: 0
Received 0 Likes
on
0 Posts
Well its just something to look at. What happened to me sounds a little different than what your having. If the clutch is rated for the torque you have only other thing i can think of is the discs are glazed or the flywheel is.
10-20-2007, 01:56 PM
#11
11 Second Club
Thread Starter
iTrader: (5)
Join Date: Mar 2006
Location: South Coffeyville, OK
Posts: 176
Likes: 0
Received 0 Likes
on
0 Posts
well i replaced the clutch with a LS7 clutch kit and that fixed it. The old clutch however did not look bad at all as far as wear goes. Everything looked good so im guessing that pp was just bad after all. The FW still looks brand new so if anyone needs a almost new stock fw, lemme know....
