Clutch shudder from standstill when hot

Hi all,

I've had my 1989 Power Ram 50 for about 3 years, now. It is a 5 speed manual (KM-145) with 4x4. For the 3 years I've had her, she's always done this weird thing where the clutch will behave normally until she warms up (after prolonged highway or stop-and-go driving, for example), and then shudder a lot when accelerating from a stop afterwards (and only in first gear). I'm no expert mechanic, but I have checked the cable adjustment and made sure there wasn't too much play in the clutch pedal. Still no improvement. For 3 years I've put up with it, even taking it to a transmission shop for a free inspection only to be told there was nothing wrong with it and that maybe I just needed to gas it a little more.

Did some googling and came up with something called a Bowden tube, but thought those were unique to old VWs. Any of you guys know what the issue might be?

Thanks,

Bones

might be due for a new clutch and a skimmed flywheel. might be getting a little oil on it, might be worn, might be glazed. Pressure plate can suffer metal fatigue which is most notable when hot as well

I had the same shudder issue after a long freeway drives. It hasn’t been a problem since I replaced the clutch while dealing with a seized pilot bearing. However (and to the forum at large), could the shudder be caused by flexing of the firewall?

what rpms do you start dropping the clucth? anything under 1400 on these trucks and they tend to shudder a little bit. it sounds like the transmission shop is saying the same thing as me. try to start dropping the clucth at 1600 rpms and see if that fixes your issue.

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Originally Posted by FMS88

I had the same shudder issue after a long freeway drives. It hasn’t been a problem since I replaced the clutch while dealing with a seized pilot bearing. However (and to the forum at large), could the shudder be caused by flexing of the firewall?

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It's possible, but that mostly happens if you have an uprated pressure plate on the clutch. I'd get someone to work the clutch while you watch the firewall around the adjuster. If it is moving/flexing it would be wise to reinforce the area before it cracks the sheet metal. I think the clutch friction disc/pressure plate is the culprit - could be a cheap clutch or contaminated etc as tortron has advised.

Quote:

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Originally Posted by geezer101

It's possible, but that mostly happens if you have an uprated pressure plate on the clutch. I'd get someone to work the clutch while you watch the firewall around the adjuster. If it is moving/flexing it would be wise to reinforce the area before it cracks the sheet metal. I think the clutch friction disc/pressure plate is the culprit - could be a cheap clutch or contaminated etc as tortron has advised.

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I agree that the clutch may be suspect. The Luk clutch installed by the crappy trans shop that rebuilt the trans always shuddered after long drives. Haven't had the problem since installing a Centerforce clutch.

My guess is that the flywheel needs skimming. They can get wavy, and they can get wavier as they warm up. (think warped brake rotors) Realistically, it's one of those things that you won't know until you take it apart, and if you take it apart you might as well replace it all.

bonesaparte,
Could you post pictures of the 'mounts'-- transmission, engine ?
Thank You !

OK first DON NOT take this the wrong way. I have seen so many people go to a light with a stick shift and then let the car roll back a touch. Then they slip the clutch just enough to keep the car in place tell the light changes. That is so bad on a clutch. I'm not saying you are doing that but people do it. That causes the lots of problems later on. It can even turn the flywheel blue.
I would replace the clutch.
Causes for clutch shutter. In no particular order.
#1 Warn disc
#2 bad or warn pressure plate springs.
#3 release fork arms bent causing miss alignment of the throw out bearing to pressure plate. This in turn causes 1/2 of the plate to grab before the other half.
#4 operator error.
#5 broken mortises springs in the disc.
#6 broken disc separation springs.

Thank you all for your answers and advice. I think I'll probably just end up replacing the clutch and all of its related components. I love this scrappy little truck and need her to last at least through my enlistment and then college until I can afford something else, at which point I hope to swap in a diesel and turn her into a nice overlander. Hopefully I find a well paying job by then!

@claych I'll post a few pics of the mounts for you