Engine/Transmission (1998.5 - 2002) Clutch not totally disengaging

[jdross440]

In the last few days on my 2000, the clutch isn't disengaging totally. I have to start it in gear and it drags either forward or backwards slightly. I thought it was the South Bend hydraulics (4 years old and 50K miles on clutch and hydraulics) had gone bad as it was wet where it comes into the cab. I replaced it (with a NAPA system as that was all that was available without waiting a week), but no change. Sometimes I can pump the pedal and it will barely release (let pedal up 1/2" and it's engaged).
The truck is going into Blumenthals Transmission to get synchros (and whatever needs replaced) is why I was in a hurry. It is a 5 hour drive.

 

[Sticks]

Sounds like the clutch is shot. Time for a new one.

 

[jdross440]

If the clutch is worn out after 50k miles, no more Southend clutches. Haven't towed more than 1k miles and 10k pounds max. The factory clutch lasted 150k and was abused. Next clutch was south bend and lasted 25k but installer didn't resurface flywheel. The one in it now was the 1000 ft-lb 13" upgrade with flywheel.

 

[Sticks]

gods, my brain went all backwards on that one.

I'd say the hydraulic master/slave is still suspect in this case, followed by the throwout bearing. I've thought about this just about every way I can and that is the only thing that I can see as the problem. Might be that the pressure plate is shot, springs can only take so much before they are no longer springs.

 

[KATOOM]

If you have the Southbend hydraulics then give them a call since I believe their setup is adjustable. Or either the master or the slave cylinder has a small leak. Can you pump up the clutch? If so thats generally a sign of hydraulics bleeding down.

 

[Sticks]

First post says that SB hydraulics were replaced with NAPA. Starting to lean more towards throwout bearing.

 

[KATOOM]

I missed the hydraulic replacement part..... If the hydraulics where switched to SB then its because most likely the clutch was replaced and because of the added pressure plate pressure the OEM hydo's needed to be replaced as well. You cant swap out just the master or the slave as its next to impossible to bleed the clutch hydraulics on these trucks unless you bench bleed the entire system before installing. This is why the kits from the dealer and places like SB and Valair come as a complete kit and not in pieces. I'm not sure why NAPA sells them individually. If only the master was replaced, which it sounds like was the case then thats the problem.

Also, a bad throwout bearing wouldn't stop the clutch from disengaging but would make all kinds of noise when the clutch was engaged. A bad pilot bearing would try to force the input shaft to continue spinning with the clutch depressed but again, those two bearings generally make a little to a lot of noise when they start to fail.

 

[Sticks]

I've seen locked up bearings eaten away, along with the pressure plate diaphragm "fingers". Nary a noise came from it, least what could be heard over the sound of the engine.

 

[KATOOM]

Either way, if the OP is having the syncros replaced then they should easily discover the problem when the transmission is removed.

 

[jdross440]

The Southend hydraulics was starting to leek out cab side of master cylinder. That's why I changed the system. The Napa part comes as a complete assembly like dealer and Southend system. They were the only ones around that had the system and had it in stock. Just hoping it stays semi operational for the drive.

 

[RikDavis]

I have had this problem with a bad pilot bearing. Enough slop from a powdered up bearing will keep the clutch from fully disengaging. I replaced the factory bearing with one of the brass bushing type from Standard Transmission. Of course if your in there you probably should change it all anyway. I have also had this problem with pressure plate fingers cracked

 

[Bob V]

Its not the TO bearing, but it could be the pilot bearing. If it was damaged on install it could be showing up now. Hard to tell without driving it.

 

[jdross440]

The pilot bearing is whatever Southbend put in the kit. It will release enough to start it in gear and take off. About 1\2" of pedal release its fully engaged. If you start in reverse you have to shut it down put in fwd gear then restart. Same if you start in fwd gear and need to back up.
This transmission has the small input shaft don't know if they will upgrade it of not. They said they have the parts for small shaft. They have contract to rebuild all Chrysler trannys.

 

[KATOOM]

You can upgrade to the larger 1 3/8" shaft easily for about $300.

 

[jdross440]

I don't believe it's the pilot bearing since it takes almost no pedal movement off the floor to be fully engaged. I may have them upgrade to the larger shaft so I can go with another brand of clutch since southbend is apparently the only 13" with small shaft that I have found.

 

[KATOOM]

Southbend or Valair are really the most reputable clutch companies for these big diesel trucks. And they both have spectacular customer service. There are other clutches out there available but I cant say how good they are.

 

[gtwitch]

I also had a pilot Bearing (roller type) give up at 111K and I also thought it was Hydraulics but upon further inspection it was the rollers wadded up around the input shaft and causing the shaft to try and rotate even though the throw out bearing and Hydraulics were functioning properly. Now after that new NAPA (china chincy) kit and now at 220k with a LUK kit the origional hydraulics are still fine. Check the pilot bearing!!!!

gtwitch in wyoming

 

[KATOOM]

I never hold the clutch pedal in..... The only times my clutch is touched is the few seconds before taking off from a stop light or when I'm shifting gears. Throwout bearings and pilot bearings have to endure years/miles of usage with very little lubricant. Watching people drive their manuals, its crazy how abusive they unknowingly are to their clutch system.

 

[jdross440]

I never ride the clutch. It's either pushed in to stop or it's out. Even at some of the longer stop lights I put it in neutral and release clutch. Blumenthal just called and said they had the transmission at the teardown area to see what it needs. They said the clutch was bad and that it had ruined the flywheel. As I said above this Southbend clutch only had 50K miles (over 5 years). And it has not been abused by heavy towing-been used as a part time driver. For a $900 dollar 1000 ft-lb kit, that's not good. I should hear in about 3 hours what the total cost will be. Will probably be Friday before it is completed due to Thursday being a holiday.

 

[KATOOM]

You may want to be having this conversation with Southbend too.