Clutch shudders
Junior User
Joined: Jan 2002
Posts: 68
Likes: 0
Clutch shudders
I got a '76 f-100 with a 3spd column shift. When i start out in 1st gear the truck shakes bad like the clutch is shuddering. What causes this. Could it be hard spots in the flywheel or a bad rear main seal leaking oil on the clutch plate. It only does it in 1st gear and it dont do it bad until its been run a bit or if its hot out. Works best in the morning when its damp out....go figure? Any sugestions?:-X23
Fleet Mechanic
Joined: Nov 1999
Posts: 1,415
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From: Lower 48
Clutch shudders
The problem you've got is called "clutch chatter" and you are right on the money saying it is shuddering. A couple of things could be causing it.
1) A lot of stop and go driving.
2) Loading the truck very heavy where you have to slip the clutch alot to get your load moving.
3) Larger (diameter) tires than stock will aggravate both of the above, especially with a high rear end ratio (3:08 or so).
The problem is basically you're heating up and slightly warping the clutch. A lot of stop and go traffic will do it and so will heavily loading it especially with bigger rear tires due to the fact it takes more slippage to get your truck moving.
The fix is pull the trans, and have the flywheel turned by a good machine shop and put in a new clutch, pressure plate, and throwout bearing. If you have the capabilities to do so you might mic the pilot bushing and compare it against specs or a new one. One other thing to check. I had this happen once and heard about it another time. Look at the front bearing retainer on the trans (the part that the throwout bearing rides on) and make sure it's not cone shaped - that is make sure the end toward the input shaft is not smaller in diameter than the end closer to the trans. If it is, it could be letting your throwout bearing and in turn the pressure plate engage at an angle instead of straight on as it's intended to do.
Good Luck and keep us posted.
Trail Rider
1) A lot of stop and go driving.
2) Loading the truck very heavy where you have to slip the clutch alot to get your load moving.
3) Larger (diameter) tires than stock will aggravate both of the above, especially with a high rear end ratio (3:08 or so).
The problem is basically you're heating up and slightly warping the clutch. A lot of stop and go traffic will do it and so will heavily loading it especially with bigger rear tires due to the fact it takes more slippage to get your truck moving.
The fix is pull the trans, and have the flywheel turned by a good machine shop and put in a new clutch, pressure plate, and throwout bearing. If you have the capabilities to do so you might mic the pilot bushing and compare it against specs or a new one. One other thing to check. I had this happen once and heard about it another time. Look at the front bearing retainer on the trans (the part that the throwout bearing rides on) and make sure it's not cone shaped - that is make sure the end toward the input shaft is not smaller in diameter than the end closer to the trans. If it is, it could be letting your throwout bearing and in turn the pressure plate engage at an angle instead of straight on as it's intended to do.
Good Luck and keep us posted.
Trail Rider
Junior User
Joined: Jan 2002
Posts: 68
Likes: 0
Clutch shudders
Thanks I'll give it a shot. You said mic. the pilot bearing, is it a bushing type bearing that will have ID wear? Do I check the wall thickness, or having 200k miles should I just replace it? Do you know the specs. for that, or where I can find them? I have mics to check it. Thanks again for your help.
