Shutters after new clutch installation

I have a 94 Ford Ranger 4.0L V6 4x4. I just had a new clutch installed last week and as I drove away from the shop parking lot the truck shuttered and jerked violently after the clutch had started to engage but was not fully engaged. It does this only when starting from a complete stop. Once I get through that 1.5 seconds of violent jerking it works beautifully through the rest of the gears. I took it right back to the shop and the mechanic told me that he had the flywheel turned and that the flywheel was borderline too thin so he shimmed it out. He said he would replace the flywheel and that should take care of it. He replaced the flywheel and the problem still occurred. Then he assumed the clutch was defective and put a 2nd new clutch in. The problem has improved some, but it still shutters quite a bit when I start from a complete stop. The mechanic is stumped and said he doesn’t know what else to try. Could it have something to do with the transmission not being aligned perfectly when he reinstalled it? Or could it be my universal joint? Any suggestions would be tremendously helpful. Thanks!

Did he try a second pressure plate?

At times it is possible to bend the clutch disc upon installlation of the transmission. Still sounds like a pressure plate/clutch disc issue to me.

A not so far fetched idea is missing alignment dowels between engine and bellhousing.

If a complete, high quality clutch package; a clutch disc, pressure plate, throw out bearing and pilot bearing were properly installed shudder should not occur. Were all parts replaced and what brand? Was the pressure plate’s friction surface cleaned with solvent? Was the flywheel surfaced? Was the pilot bearing replaced? Was the transmission mated flush to the block(maybe the rock gaurd was kinked)).

A problem like that should never be delivered to the customer. The problem should have been found on a road test, corrected, and the customer should never known there was a problem.

I think you mean “shudders”. Shutters are things that protect windows or doors. Shutter can also be a verb as in “I shuttered the windows”.

I’m not sure what brand the mechanic used, but he said that he replaced all components including the slave cylinder. I doubt the pressure plate was cleaned with solvent however. I appreciate all these suggestions.

I’ll have to ask him…he said he put in a second clutch and I assumed that meant pressure plate too. Think that could be a likely cause of this problem?

A mechanic would use the word “chatters”

One thing that should be looked at is the engine and transmission mounts. If there is excessive flex in the mounts it can cause a clutch shudder.

He checked all trans & motor mounts & said they were solid. Not sure… I’m taking it back this afternoon & leaving it with him until there’s no chatter/shudder/shutter.

Shuddering like that used to be caused when a clutch pedal was set to engage with the pedal too low. We used to get rid of the problem by adjusting it to engage near the top of the pedal travel. I don’t know if that works with a hydraulic clutch. Then there is the loose rear mount or center driveshaft mount.