Weird Clutch Issue

2000 TRD OR, 3.4, MT

So, over the weekend I went snow wheeling with a group of Jeeps.

I was climbing a hill, from stop, in 3rd gear in 4lo with the front and rear lockers engaged, running into a snow bank, gaining about 10 feet on every charge. I was slipping the clutch a little to get it going but then I was all out of the clutch. After about 4-5 charges I was through the snow bank and scrambled the rest of the way up the hill.

I shut the truck off for a bit while I was waiting for the Jeeps to clamber up. A Gladiator Willy's with the rear locker got stuck and had to be pulled out. Eventually, maybe 30 minutes, we decided to run back down the hill and take some more trails.

Truck started easy, like normal. It may have been slightly difficult to get into gear, but that's normal for this truck.

When I got to the bottom of the hill I was in first with the clutch in and I could feel, through the brakes, the truck trying to pull itself forward. It didn't want to come out of gear. This is not normal. I pulled a little hard and it popped out of gear with a little grinding of gears. Then the clutch pedal would only come up halfway. I'd push it in and it would only come back halfway. I used my toe to pull the lever all the way back out. After pulling it out, the clutch worked fine.

We drove back to the trailhead and it did just fine. It felt normal. We left it at the trailhead and finished our wheeling trip. It drove home, about an hour, just fine. The clutch feels normal.

It did this once before and I replaced the clutch slave cylinder. I'm not sure how I came to the conclusion that it was the slave but that was about a year ago.

What could cause an intermittent failure like this? I was working the clutch pretty hard. Could it have frozen halfway out? I'm leaning towards the master cylinder. Anyone ever have this issue? I don't want to replace the master and assume it's fixed. I also don't want to replace the clutch. I don't want to do that job myself.

Sorry for the long winded question. Help is appreciated in advance!

 

An air bubble! Id bleed the system.

 

This actually sounds plausible. Good idea! Great place to start anyway.

 

Clutch pedal not coming back up with these trucks is frequently caused by the clutch pedal return spring. It's a goofy coil spring setup. The plastic bushings on it wear out, and then the slot in the clutch pedal that it rides in wears deeper. Most people just pop the coil spring out and replace it with a linear spring. The points to connect it to are already there because the 4-cylinder models use a linear spring. A brake pedal return spring, or a clutch pedal return spring from a 4-cylinder will work. Here is a thread about it https://www.tacomaworld.com/threads/clutch-pedal-truffle-shuffle.499079/ Might as well give it a try, it's a five minute repair an will cost you all of $10

 

Is there enough fluid in the master cylinder to prevent the port from sucking air when the truck is on an angle?

 

Master cylinder is full. There is no way I was at any kind of angle that could have allowed for air ingestion. There was quite a bit of side to side acceleration as I pushed through the snow bank but I think due to the fluid level in the MC air ingestion is improbable. It's at the top top of the full markings. Fluid does look old.

 

I will look into this. This also sounds like a plausible cause of my problem.

 

I ordered a new clutch master and slave cylinder for just under $100. AISIN parts.

I figured I'd just replace both and id have an all new system and hopefully catch the culprit.

Now after reading some of the solutions above I might try the clutch return spring swap, depending on what mine looks like when I get under there.

"If it ain't broke don't fix it."

I'd be happy to return the parts and get my $100 back.

On a side, possibly connected, note. My cruise control does not function. I think it's the only thing on the truck that hasn't been working. The clutch pedal has always had a small amount play in it. Probably an inch or so. I bet just enough not to depress the cc switch. There is a possibility the linear spring kills 2 birds with one stone.

 

Could have overheated the clutch so badly it boiled / overheated the brake fluid.....
from the slipping of the clutch, maybe its was worse than your conveying.
Regardless, doesnt sound good, beating-up your clutch is never fun or a good thing...

 

I wasn't too rough on the clutch. Due to the location of the slave cylinder the clutch could melt before it would cause the clutch fluid to boil.

And climbing that hill was the most fun I had all day! I wish I had a video!

 

Now I'm even more convinced it's your return spring.

 

I bet if you use your toe to pull the clutch pedal up, and hold it up your cruise control will work. That is until you let go with your toe.

 

What is wrong with the CC exactly
What is it doing that is abnormal

 

It doesn't do anything at all. No indication that it is on and it doesn't work.

 

So I tested pulling the clutch up with my toe to see if the cruise control would work. No dice. I still get nothing.

Thinking about the return spring, I do not think it could be the line issue. If it were just the return spring the clutch should have still fully disengaged when I pressed the pedal to the floor.

I'm thinking this has to be a failure of the Master Cylinder. I just don't understand how it "fixed" itself.

I'm going to try working the s#it out of it when I get home and see if I can get it to fail.

Real head scratcher here...

Edit: I depressed and released the clutch like 50 times when I got home. No change in pedal feel. Clutch still works fine.

 

You said you replaced the slave cylinder once before? Did you replace the master cylinder at the same time?

you should always replace both if one fails. 100 bucks worth of parts is worth it.

 

I did not. I only replaced the slave. I have a master and a slave on order. So I'll replace them together this time.

 

You may have introduced the bubble when changing the slave, then inverted the truck on a hill climb??? Your symptoms will come and go as the bubble travels through the system. But if it lodges in a bend in the line, it will A exacerbate your symptoms and B won’t go away until you take the line out and make sure the bubbles come out. I found straighten and banging the line works.
Try the spring trick first, if it still doesn’t disengage all the time find the air bubbles! Dont open those new parts just yet…