Clutch Malfunction - Bizarre

The wife, a close friend and I did a 1 month tour in the general Death Valley area and surroundings and I experienced a very strange clutch malfunction where I am still not confident about the root cause issue. The vehicle is a 2000 Tacoma, 3.4L, 5 speed manual with the TRD 2nd Gen supercharger.

We were headed towards Panamint Springs on Towne Pass near the summit and my vehicle was loaded up with camping equipment, coolers, firewood, extra gas and water. The grades are so steep that I was shifting between 2nd and 4th gear trying to maintain acceptable speed.

I went to downshift but the clutch only returned to the 50% point. When I depressed the clutch to the floor it would not fully disengage so was unable to shift. Coasted to the non-existent shoulder and cringed as big motor homes passed me on the blind hill. Yikes!

Fortunately, my buddy with an old HiLux was behind me and put a tow strap on and got me to one of the brake pullouts after the summit.

After some discussions we decided the best course of action was to have the truck towed to Pahrump, NV so we could diagnose the problem and if necessary replace the clutch. Found Pro-Tow & Recovery in Ridgecrest and the next morning they towed me. Very professional, fair in price with good equipment. Couldn't be happier with the towing aside from the $$$.

In Pahrump discovered that the clutch now worked perfectly and drove it around town for 15 minutes with no issues.

After brainstorming we decided it would be suicide to take the truck out in the back country without replacing the clutch so spent the next 2 days on a friend's driveway pulling transmission/transfer case and putting a NAPA clutch pack in. Also flushed a whole pint of brake fluid through the clutch master & slave cylinders. The fluid was very dark in color and opaque.

The vehicle had 60K miles on it at the time and the clutch, throw out bearing, pressure plate and pilot bearing were in perfect condition. The clutch plate looked to be about 50% worn.

After replacing the clutch we spent the next 2-1/2 weeks driving trails and zigzagging across the paved roads of Death Valley with no further problems.

The only theory that I have come up with is that under high engine load with the supercharger that I overheated the clutch fluid in a section of tubing near the drivers exhaust manifold. I had been running the engine pretty hard at about 3,400 RPM in 3rd gear to maintain 50 MPH and I suspect the manifold was plenty hot. After putting the new clutch in I wrapped several layers of aluminum foil around the suspect section of clutch tubing as a heat shield.

The only other repairs I am considering is to replace the slave cylinder and possibly the master cylinder. The problem is both master and slave appear to function perfectly with no fluid leaks or any other problem that I can see.

Anyone else ever experienced a problem like this?

 

Can't say I have, and I have pretty much the same setup. 2004 Tacoma 4x4 5speed manual with black TRD supercharger. With 33" tires, roof top tent, bumpers, sliders, skids, etc. she's pretty heavy. Haven't done Death Valley but have driven up and down all kinds of steep grades both asphalt and dirt, never had a clutch issue like that before. I've only got 87k on my truck though. Subbed to see if anyone else might know...wondering if it's something to do with the clutch slave cylinder

 

Sometimes a contaminant like a piece of deteriorating rubber from a seal in the master or slave or hose can get caught under the lip of the seal in the master and cause that problem. Next time you have pedal problems with no disengagement ALWAYS look at the hydraulics first. You probably could have bled it right there on the side of the road and got going again. Or even just pumped it a whole bunch to work the contaminant free.

A slave cylinder problem will exhibit itself as an external leak. Only a master can fail without leaking externally. Yeah, yeah- I know. A slave can sieze. But we are talking vehicles that get driven, and not parked for more than 10 years.

 

I should say I had an issue once with the clutch pedal not returning all the way up right after I got a new clutch installed at about 50k. Would return 3/4 of the way then I'd have to pull it up with my foot the rest. Ended up needing to bleed the slave cylinder and that took care of it, but it wasn't a completely clutch failure like what you experienced. Still worked fine just wouldn't return all the way

 

There is a little plastic and metal coupling thing that threads on to the clutch master and connects to the pedal. Lay on the floor and press the clutch pedal, they crack inside and gets stuck kinda crooked thus not depressing the master completely. It’s a random thing too. I was unable to buy just that coupling thingie so I just replaced the whole master for a friend. It’s like 25 bucks, 25 minutes. Add a linear spring while in there...

 

Thanks, I will look at that. We spent some time upside down in the cab looking for anything that could have jammed the clutch behind the firewall but could see nothing amiss.

 

Being your Fluid was dirty I can go with the idea things got hot!

I hope you saved all your old clutch parts

 

I can almost guarantee it's your 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. Pop the coil spring out and replace it with a brake pedal return spring. It’s a linear spring. Here is a thread about it https://www.tacomaworld.com/threads/clutch-pedal-truffle-shuffle.499079/ Sorry you had to spend all that time and money on something that you can fix in five minutes with an eight dollar part.

 

At least they did the clutch themselves though and didn't pay some crazy shop (or worse yet, dealership) rate to have it done. Been there done that, got the wallet raping PTSD from it to this day

 

Here is another thread on the subject:
https://www.tacomaworld.com/threads/linear-clutch-pedal-return-spring-pictures.350433/#post-22241071

 

I will take a very close look at the return spring and the coupling.

Thanks for the tips.

And yes, I did unnecessarily dump $330 on a new clutch pack but after $1K towing that hardly hurt!

 

A $1k tow??? Holy crap that hurts

 

Wow! Damn, for $1K you could have almost bought a used car hauler trailer. Should always do a quick search on TacomaWorld first. With only a screw driver you could have popped that coil spring out and continued on. It will work without a return spring. The pedal won't come quite all the way up, but you can drive it. Cruise control might not work because the pedal might not come up high enough to touch the cruise disconnect switch, but still could have avoided the tow bill. My truck had the same problem. I wasted money on new master and slave cylinders. As well as a bunch of time flushing and bleeding the system several times. Ultimately found the solution here on TacomaWorld. In fact that is how I found and ended up joining TacomaWorld.

 

Gyrkin,

Please tell us the solution.

Paul

 

I had a similar issue. Trying to leave home and could not get the truck in gear.

pedal was not returning all the way so my new effort to engage the clutch was not working.

till I can get a new spring and bushings installed I just use my toe and pull up on the clutch pedal to make sure it comes all the way back up.

 

Remove the coil spring and replace it with a linear spring. A brake pedal return spring works. A clutch pedal return spring from a 4-cylinder model also works. Heck a decent spring, the right length, from the hardware store will work.

 

You can just remove the coil spring for now. It will work better without it, until you can get a linear spring. The pedal might not come 100% of the way up, making your cruise control not engage, but better than fishing it up with your toe all the time. No need for bushings with the linear spring.

 

If you time it right, you don’t need no stinking clutch... just don’t turn it off

 

Found a couple of photos on the interweb that should help.

This is what it looks like stock. You can see the big coil spring.


Here is what it looks like with the linear spring. The connection points are already there because the 4-cylinder models use a linear spring.


Here is a writeup about it:
https://www.tacomaworld.com/threads/clutch-squeak-linear-spring-swap-tw-how-to.159429/

 

Curiously, I have had the problem that Gyrkin is describing on another nearly stock 2000 SR5 3.4 L Tacoma 4WD. Clutch squeaked badly and only returned about 7/8 of the way. However, when depressed to the floor the clutch disengaged and this never affected shifting. I used my toe for about a year to lift the pedal back up just because I was worried it was not fully engaged before I took it to my good local shop for major maintenance and they fixed that problem at the same time.

In the recent failure the clutch only returned to 50% point but when depressed to the floor it was like the slave cylinder was only actuating 50% or less. As I indicated, after towing the clutch worked fine before I did any work on it. I did not bleed the system until after we installed the new clutch pack.

In addition, when the new clutch pack was installed I didn't replace any parts on the master cylinder, slave cylinder or the linkage that connects the clutch pedal to the master. Did 2-1/2 weeks of fairly serious wheeling, drove 1,000 miles back to Washington State and have been driving 4 times per week for the last 6 weeks. Clutch pedal makes no noise, is perfectly smooth and has completely normal feel and range of motion. If there is something wrong with the linkage or the return spring it is hard to understand that there isn't the slightest indication of any roughness or malfunction through the range of pedal motion.

I probably won't focus much effort on this until spring when it becomes more pleasant to do this work on my driveway. If I can put my finger on the root cause will update the thread.