1st Gear Clutch Shudder

wilke3169 · 04-30-2009, 07:37 PM

I did a search and didnt find anything exactly like my symptoms.
My '79SC has developed clutch shudder. The odd part is, it's only in first gear. The shudder is quiet violent to the point that I limped home and won't drive it again until I sort it out. Odd thing is I can start in second from a dead stop and there is no shudder at all. At speed in any gear, including reverse, no problem.

Short history; Engine rebuilt 25,000 miles ago, Transmission changed out a year ago with a rebuilt but used 915. Clutch, PP, cable, etc replaced at engine rebuild.

Any help? Any similar experience?

Thank You,

NineOhOne · 04-30-2009, 08:20 PM

Same problem here. Subscribing.

oregonmon · oregonmon's Garage

Somewhat similar prob, but maybe not. I have new clutch but get a bad shudder if I release the clutch in 1st too quick. I may be having my tranny mounts replaced.

msk1986911 · 05-01-2009, 03:03 AM

Is the clutch cable properly adjusted?

kucharskimb · 12:36 PM

Shuddering Clutch 915

The answers are in this thread... The leak, the fix, the dam seal and hole mod, etc.
good luck

T77911S · 05-01-2009, 04:10 AM

mine got better when i did another clutch cable adjustment, but it still does it.

i have also considered broken springs on the disk.
one thing i have not heard anyone mention are hot spots on the flywheel. if you look at the surface, you will see blueish spots where ?aneiling? took place. i think that is what it is called, anyway, the spots can cause the clutch chatter.

wilke3169 · 05-01-2009, 04:22 AM

After reading kucharskimb's thread from a few years back, I believe I have direction. The transmission was installed last year, as stated. It always had a few drops of oil which I assumed, I know never assume, were an external leak. With these symptoms I am thinking I may have a main seal leak that has allowed some oil to find its way to the clutch disc. I will check mounts, adjustments, etc. but this sounds too much like mine to be a coincidence. Combine that with "blue" i.e. Swepco on the tranny case and I think I know the source of my shudder.

Walter_Middie · Walter_Middie's Garage

Quote:

I will check mounts, adjustments, etc.

Don't forget to check the bolts that attach the transmission to the engine. If those 4 bolts get loose, the clutch will chatter like crazy.

jmohn · jmohn's Garage

Quote:

Originally Posted by msk1986911

Is the clutch cable properly adjusted?

This is what I would do first and be sure there's enough compression on the bowden tube portion of the cable assembly. I know from experience if that tube portion does not have sufficient compression ("bowed up") there will be considerable clutch shudder.

Jerry M
'78 SC

wilke3169 · 05-02-2009, 07:30 AM

I checked all of the adjustments and the mounts for tightness, play, etc. Adjusted the clutch til it is dead on. Still shuddering rather violently.
I am still puzzled that this only happens in 1st gear??? I can pull off in 2nd and no shudder, No problem in reverse, I can even put the car in 3rd and allow the clutch to engage slightly and there is no shudder.
I will add the fluid that is on the bottom of both the engine and the tranny is too much. It is quite possible that i have a leak that is contaminating the clutch disc. I will continue to scratch my head and hope for something obvious.

wilke3169 · 05-10-2009, 05:40 PM

Pulled engine and transmission this weekend. The rear seal on the transmission was shot. Oil was being directed via the guide tube directly to the pressure plate side of the clutch disc. I replaced the clutch disc and all is well.
Thanks to everyone for the suggestions,

Kevin

kucharskimb · 05-10-2009, 05:53 PM

Sweet!!

Gogar · 05-10-2009, 06:10 PM

Kevin, do a search on

"dam seal"

and

"guide tube drain hole" (or something similar.)

These are two cheap easy things you can do so the next time your seal fails, the trans fluid will get directed downward and out, instead of getting flung onto the clutch disc.

kucharskimb · 05-11-2009, 09:55 AM

Yeah, the dam seal was in my article. I felt bad asking...

Superman · 05-11-2009, 10:19 AM

Adjust the clutch. Make sure the Bowden Tube arches over the throttle linkage.

New clutch cables help a LOT.

Make sure your motor mounts are in good shape and are not loose.

New clutch disk.

Make sure your transmission input shaft seal is doing its job. Oil-fouled clutch disks are usually fouled with transmission oil, not motor oil. Engine rear main seals rarely leak and if they do, they foul the rear-side of the flywheel, not the clutch disk. Transmission input shaft seals, when they leak, they allow oil to crawl up the input shaft and get directly onto the clutch disk.

But again, the first things to look at are cables and cable adjustment.....and motor mounts. The bad news here is that nine times out of ten, it's going to be a wet clutch disk.

Grady Clay · 05-11-2009, 10:30 AM

Kevin,

Good that you found the issue.
Be sure and install the ‘Dam Seal’ mod.

What year and type 915 did you install at the change? The issue here is the type of clutch release (TO) bearing guide tube. There are at least three versions.

It would be useful if you can post pictures of your ‘Dam Seal’ mod so others can see. I have a couple of versions here I can use.

Best,
Grady