Engine/Transmission (1994 - 1998) No clutch engage/disengage

[JHastings]

Out of nowhere today, my clutch decided to stop working (didn't want to come out of gear when on the off ramp). Pulled the master cyl cap and pumped, no bubbles. Clutch has 75K on it. No slipping... .



Is there a plastic piece on the end of the slave rod that can wear out? Seems like any wear items should wear out slowly over time and not overnight.



Any ideas?



Jamie

 

[snappy]

Can you put the transmission in first or second with the engine off, then start the truck and move? There is a plastic button on the end of the slave, but this problem is not that.

 

[JHastings]

Yeah, I got it through all 5 gears, but I had to rev it and time it right.

I don't see any leaks on the master/slave and there is no loss of fluid. Any chance it is the clutch itself?

How does a guy diagnose it?

 

[GCroyle]

JHastings,



I'm interpreting your thread as FAILURE TO RELEASE. You cannot select any gear from a standing start.



The nylon cap at the end of the pushrod acts as a smooth surface or bearing for the pushrod to the fork, minimizes wear on steel to steel surfaces, not available as a service part to my knowledge, comes with new slave cylinders.



The only external diagnosis for a system that was working and now no longer works is the hydraulic system, remember we are accepting that it was working fine up until the FAILURE TO RELEASE situation.



We recommend testing the complete hydraulic system by blocking it with a steering wheel puller and testing as demonstrated here YouTube - perfectionclutch's Channel if you do not use some method that completely blocks the slave cylinder with steel, the test will not be valid.



If it passes the above test, then time to think internal. Any component of the disc that breaks away from the disc can wedge into the system somewhere and cause failure to release.



Pilot bearings have been documented to cause failure to release when they wear out and jam up causing the input shaft to rotate as you try to release the clutch.



You state out of know where it failed, OK, but there are possible driving induced failures. It is rare but I know it has happened on some trucks and I have 1st hand info on a HI gear to WAY LOW downshift that overspeeded a disc and burst it. I have seen the results of extreme downshifting that can bend the drive straps that create and control pressure plate lift and release from the disc, it might take a big load and a strong downshift into a skipped lower gear. This is easier to do on smaller "quick" gearboxes.



Just as a note to our TDR community many years ago I personally spoke to a car owner/parts purchaser/installer that DESTROYED a very expensive clutch and the tires never hit the ground. He drove it on the lift and somehow did a HIGH RPM deceleration that kinked the drivestraps ruining the clutch. I also saw the aftereffects of this practice on a certain Porsche application for years in a previous life. No need to do a test drive on the lift.



A standard diaphragm spring clutch in typical service will generally exhibit only one warning symptom of wear, but it can be hard for the truck owner to interpret. The release load gets harder and harder as the disc gets thinner. The exception to this is the G56 OE Self Adjusting Clutch. As the pedal effort gets harder the next typical failure is slipping under high power use.



Good luck.

 

[hsmith]

If the hydraulics are ok I would suspect the pilot bearing.

 

[snappy]

So would I.

 

[TBartlett1]

Not sure if the clutch mechanism for a 2nd gen is the same as 1st gens but I will relate my problems & solutions.

1) My 1990 clutch stated to drag making shifting difficult. I found it was the front input bearing failing in my Getrag. A new NV4500 cured that problem.



2) The clutch master link and pin where the master connects to the clutch pedal wore out thus not depressing the master cylinder fully which caused the clutch to drag. The cure for that problem was to remove the master and replace the eyelet on the push rod with a spherical bearing. I also removed the clutch pedal because the pin was worn ½ way through. I ground the weld on the back of the pin removed it from the clutch pedal and replaced it with a bolt & nut. I then attached the new end (spherical bearing) using the nut & bolt.

To remove the master I cut the plastic tubing with a tubing cutter and then repaired it with a 5/16 or 3/8 compression fitting. I cannot remember the size because this was many years ago. This fix is still working.



3) My last suggestion;

I had a 2005 and the clutch suddenly stopped working. I found that the owner while getting out of his truck started to fall out and got his foot caught under the clutch pedal which pulled the piston out of the master cylinder. A new slave assembly was required to fix this.

Check for brake fluid under the dash if the floor is wet you found your problem.





Hope this helps.

 

[MLee]

Jamie;

Same symptoms as yours. The first time when on a trip, Hydraulics, replaced it worked fine. This year on a trip, same symptoms, replaced the clutch Hydraulics, no go. Went to the dealer, Replaced the clutch, springs were broken on the clutch disc and the pilot bearing was gone. Hope yours is the cheaper of the two.

 

[JHastings]

Thanks for all the help. I'll diagnose it tomorrow hopefully and let you know.

Thanks,

Jamie

 

[JHastings]

Spoke with Peter at SBC the other day and he sent out a 13" Con-o. (Great Guy) Got it and took everything apart last night. Result is a thrashed needle bearing. It came out in about 100 pieces. Input shaft is still good though.

I took transmission and TC out together with a big truck transmission jack. No problem there. Everything should go back in tomorrow and I also did a rear main seal at the same time. $85 for the seal though. Ouch.

Just for a follow up in case anybody has the same problem.

Thanks for all the help.

Jamie

 

[JHastings]

As a follow on in case anybody searches for clutch replacement, I will give a couple of problems I encountered so that if you do it, you can avoid them.

1. When you are replacing the clutch and you add the supplied washer (in SBC kits) to the rear of the clutch pivot ball, use some heat, PB blaster, hit with a hammer... before you try and to remove the pivot ball. Mine broke with the stud in the bellhousing. It was PITA to get it out of there and could have been avoided. Also, this is a dealer part and not one you can find at NAPA.

2. If you plan on replacing your rear main seal, be very careful not to score the seal housing when you remove the seal! I did when I was drilling into the seal to pry it out with screws. Obviously better than scoring the crank, but still not good. Drill directly into the rubber part of the seal so you won't hurt the housing or the crank. The seal should pry out easily with 2 #10 metal screws in the seal (givving you something to pry on).

3. I did my pinion seal at the same time. Very easy to do. I had to add a speedy sleeve as my pinion was scored. $40 for the sleeve and a a bit of money for the seal. You need a 1 7/8" socket, impact to get it off, and a big cheater pipe to get it back on. Punch dots in the nut and pinion/shaft so you know how tight to get that nut on there.

4. Use a transmission jack to get the transmission and TC out. I used a big truck one and it worked great.

5. And most important, the SBC kit is awesome and well put together. It came with a new style pilot bearing that won't wear out like the needle bearing will. I recommend them.

Jamie