A little help with a clutch issue? (94 V6, 4WD)

[ewhite]

Hi Folks,

New to the forum, despite having this vehicle since it was new .

Having a bit of a problem that I'd love some second opinions on:

The clutch has been going along functioning fine for ages. All of the sudden about a week ago, as I was driving along, going from 4th to 5th, it simply would not go into gear - it was exactly as if the clutch wasn't depressed. Rolled to a safe stop, tried several more time, nada. Finally, after waiting/trying a few more times, it re-engaged and worked again as if nothing ever went wrong.

Fast forward a few days, and it does it again, except this time from a parked position - couldn't even get it into 1st (reverse didn't work either). Park it over night, next morning all is fine again - clutch works exactly like before.

My mechanic is thinking complete clutch replacement to the tune of $900, even though after 6 miles of driving he couldn't reproduce the issue.

Your thoughts? Could this be a bad clutch master cylinder? Do you think I really need a full clutch replacement? (ouch!!)

TIA.

 

[chevtruknut]

Are you using any clutch fluid (its actually brake fluid) from the M/C for the clutch? If so, when it goes out can you "pump" the clutch and get it to work? I suspect it might be the clutch master or slave cylinder. Using fluid would be a definite, but they can go out without using any fluid also. Hope this helps, feel free to contact me for any more information. Brad

 

[ewhite]

Thanks for the reply Brad. The fluid in the clutch cylinder is full, and pumping does no good (sorry, I should have mentioned this in my original post). I don't see any slave cylinder however...

 

[Steve8v92]

Im not sure as I have never worked on your truck but on every car I've ever had a juice clutch on, there is a master up top where you can add fluid and a slave near the actual clutch itself.
Try bleeding the upper and lower cylinders out it could be air or the line could be rubbed through or whatever.
If your 4 runner is moving down the street without it slippin I would say it is not the clutch and most likely the above.
Good luck

 

[ewhite]

Thanks Steve, you've summed up my thoughts as well - if it rolls well sometimes, then it can't be the entire clutch, right? More likely something just isn't makin' the damn thing move, and since it is hydraulic that's what had me thinking about the Master Cylinder (didn't know about the slave, I'll check into that - thanks for the tip).

 

[ewhite]

I should mention also, my mechanic mentioned that he suspects the "pilot bearing". It's been a long time since I've worked on a car at this level, and I'll admit my ignorance - I don't even remember what a pilot bearing is/does.

Does that like a reasonable root cause?

 

[the_dingman]

There's a lot of things that could cause your problem, and with pretty much anything but a hydraulic problem (which is really ruled out if you're not low on fluid) you'll need to separate the engine from the transmission, which is the expensive part of the repair... A full clutch replacement should replace the clutch disc and pilot bearing, and in the process your mechanic should be able to see if there's anything else going on.

 

[drmorbius]

I should mention also, my mechanic mentioned that he suspects the "pilot bearing". It's been a long time since I've worked on a car at this level, and I'll admit my ignorance - I don't even remember what a pilot bearing is/does.

Does that like a reasonable root cause?

The pilot bearing is located in the end of the crankshaft and receives the input shaft from the transmission. I doubt that this is the problem. As the clutch disk wears it gets thinner which means the slave cylinder must push it's piston farther to release the clutch. There is usually a free play adjustment where the slave piston meets the release fork. You may just need to adjust this gap. If you have someone sit in the truck and push and release the clutch while you look at how it's working from under the truck the problem may be visible.

 

[ewhite]

Thanks for all the feedback everyone. I wanted to provide some follow-up on this, if anyone is interested.

the mechanic had checked out the hydraulics and linkage first, and it was all fine, so we decided to just go for the clutch. Turns out what he found were some broken springs in there, which was definitely the problem.

Funny thing is, and I didn't realize this until we starting dealing with this - it is the original clutch! We got 190K miles out of that damn clutch! Our mechanic said we were down to about 1/32nd of an inch on the plate, so I don't feel so bad about paying up anymore - we certainly got our money's worth!! LOL!