Shutter on clutch release.

[Mark B]

I have a 1970 C10 that shutters badly when I back up an incline. It shutters when the clutch grabs and the truck starts to move. I had the clutch replaced and broken motor mounts replaced, but problem is still there. The warped flywheel was also trued up. The truck is a shortened LWB, leaf spring, 3 on the tree. The transmission has no rear mount to the frame, nor does the driveshaft. The truck didn't always shutter this way, so I don't know what the problem may be.

Does anyone have any ideas for me?

thanks

[jhow66]

Rebuilt clutch-going to a "new" plate and disc will solve it.

[OrangeCrush1970]

Originally Posted by jhow66

Rebuilt clutch-going to a "new" plate and disc will solve it.

x2. sounds like a worn pressure plate

[Green Machine]

Backing up always seems worse, we have 2 trucks with manuals. However I fought this on our 68 for quite a while, still does it some though. Went through two flywheels, all reground, 3 sets of new pressure plates and disks.

With the inspection cover off, engine runningl carefully look and see if the disk rotates smoothly or goes up and down.

Turns out the replacement disks I was getting, the lining was not centered with the hub. A close look at it and even another new one, you could see the gap between the center spring hub and the lining was not centered. They finally let me exchange the new disk in the kit with a rebuilt dsik that was centered. Good thing they warranted all the parts. Parts were from NAPA.

Put the 99 dollar special from Norhtern auto parts on our 1970 C10, No problems with that one. I guess you need to inspect the disks real close to be sure they are centered.

[lts70]

I put a new clutch and flywheel in from Napa and my truck shutters on clutch release when going from a dead stop into first gear then it is fine after that. Some times it is really bad and some times it is barely noticeable. My motor mounts are new also. If I have the same problem with my clutch plate being offset will I need to change out my flywheel again? It has been like this for 3 years trying to figure this one out I hope it has not ruined it.

[jhow66]

Remember,guys, that there is a differance between new and rebuilt.

[Old Chevy Mech]

I had that exact same problem.....replaced the clutch, pressure plate, pilot shaft bushing, and throw out bearing. Scuffed up the flywheel (It looked beautiful after 200k miles (all my miles) proud to say) and it worked flawlessly ever since.

Frank

[mahanian]

Originally Posted by Old Chevy Mech

I had that exact same problem.....replaced the clutch, pressure plate, pilot shaft bushing, and throw out bearing. Scuffed up the flywheel (It looked beautiful after 200k miles (all my miles) proud to say) and it worked flawlessly ever since.

Frank

[MikeN]

I'm on my THIRD clutch/pressure plate from NAPA, with two separate re-surfaced flywheels, and still have moderate to severe chatter. I guess I'm going to suck it up and pay for one from RAM or Hayes or someone like that. I've looked at motor mounts, tranny mounts, u-joints, everything. I don't know what else it could be besides poor quality clutch/pressure plate.

[mahanian]

Be sure to replace the pilot bushing! Slop in the shaft will amplify any clutch chatter.

[Green Machine]

Don't know if we are helping Mark B any, but it looks like NAPA has some clutch problems. I think Napa pressure plates are ok but the disks, atleast the 11 inch Chevys suck. I went through three sets under warantee. The NEW disks were out of round. The REBUILT disk I traded them for - and is in there now - actually ran true.

[dwcsr]

If the flywheel was badly heat checked and the hard spots go deep enough all the resurfacing in the world won't help. Common things that happen to cause the same problem you had are, the fly wheel is no longer serviceable and the 12 year old cutting it at NAPA doesn't know that it should be replaced. Even the smallest amount of grease on your fingers with cause it to heat check and hard spot the flywheel. Pilot bearing should always be replaced with the clutch disk.. In 40 years and probably 200 clucth jobs I have never had one come back that I replaced the entire assembly. pilot , flywheel, throw out, and clutch and pressure place, AND buy new. A resurfaced pressure plate is as bad as a resurfaced flywheel.

[Mark B]

This is all really helpful. I hate to think the new (actually, Ill have to check if they but in a rebuilt) clutch is defective, but it all makes good sense. Thanks everyone. Any more opnions are still welcome.

[jhow66]

The reason a rebuilt disc does not work sometimes is that the center springs are not replaced. These springs are what take up the shock when you engage the clutch. If they are weak, they with catch and release to soon so that the disc slips back and forth.

[Old Chevy Mech]

Let me qualify what I put in;
Heavy Duty 12" clutch kit from NAPA.
Old Pilot bushing was worn pretty bad, I suspect that was the culprit. Real pain getting old bushing out.

Frank

[jhow66]

Originally Posted by Old Chevy Mech

Let me qualify what I put in;
Heavy Duty 12" clutch kit from NAPA.
Old Pilot bushing was worn pretty bad, I suspect that was the culprit. Real pain getting old bushing out.

Frank

"pain"--next time fill hole with heavy grease and take a used front shaft ans insert it in bushing hole and drive out with hammer (add grease as needed).

[Old Chevy Mech]

Originally Posted by jhow66

"pain"--next time fill hole with heavy grease and take a used front shaft ans insert it in bushing hole and drive out with hammer (add grease as needed).

That was tried, but due to the bushing be excessively worn after 200K+ miles, the grease squirted out around the shaft!

Frank

[truckdude239]

i just put a new ac delco clutch in ym truck turned the fly wheel no problems. after all ym problems with after market parts everything will be acdelco for my chevy and motor craft for my f-150