92 4 Runner 5 spd manual. Been doing it for a long time. Mostly in 3rd gear, when the speed and rev are right the whole car will start lurching violently. I used to let off the gas and it would get worse till it got down to idle speed or put the clutch in then smooths out. Recently I discovered if I give it more gas, IE rev it higher, it will stop faster. My guess is the clutch disk is worn and is slipping but I really have no idea. I hardly ever drive it so never been able to demonstrate it to a friend or a shop.

Thanks,

 

how many miles on this clutch?

 

slipping clutch is like your tires are on ice. revs without going. The violent shaking you describe could be trans mount.

 

You could be more specific, is this when you are already in gear and hit that rpm? do your rpms increase when this happens like the clutch is slipping? is this when you shift into gear like clutch chatter? if you push in the clutch does the lurching stop immediately? Any loud noises involved?

 

About 130k miles on it.

Does it in gear, not shifting. RPMs dont increase unless I give it more gas to stop the lurching.

Its nothing like slipping on ice so sounds like its not a worn clutch slipping.

So if it is the trans mount that means the mount is loose?

Thanks

 

this doesn't sound like your clutch, you should check all of your u-joints, double cardan joints motor mounts, transmission/tcase mounts. Something is loose or your engine is cutting out/misfiring or something.

 

I know what it's like when the motor mounts are loose and the engine is cutting out. It's not that it's physical lurching entire vehicle. So I'll check all those other mounts. I've had it for 20 years. Didn't do it for like 10 years and has slowly gotten worse over years. So loose mounts make sense.

 

It's hard to troubleshoot issues like this from far away, my assometer is calibrated for direct contact.

 

It almost sounds like you have your rpms to low for your speed .

Like if you shift into 5th instead of third which I tend to do all to often

 

To still have a factory clutch at that many miles seems doubtful. It possible a disk cushion spring failure or some such but as others have said, motor mounts, trans mount U-joints are much more plausable.

 

My guess is its something past the Tcase in the drive train. Another test you could do it pull the rear driveshaft and drive it around in 4wd, now front wheel drive. That would help isolate and eliminate or identify if its in the rear driveshaft or rear end.

 

Awesome idea! Thanks!

 

This.. And it's really bad for a chain drive