Clutch Issues

[unclehoser]

Well, gentlemen, it's been quite a while since I felt the need to post a question here, but I just lurk and read a lot! My time has come...

Truck is a 2002 F250 7.3 PSD with a ZF6 manual trans, not a 4x4. I purchased it pre-owned in January 2017 with about 204,000 miles on the odometer. About 3 years ago with 241,695 miles on it I had the clutch replaced and the u-joints, etc. in the driveline repaired as necessary.

Fast forward to today... About 3 years and about 22,650 miles added (odo at 22,646 today) the clutch is now slipping like crazy. If I apply a bit of throttle at or near a lower shift point (say, 25mph in 3rd gear) it just flat lets go. The engine RPM jumps, but truck no move!!! I'm also experiencing a lot of "jumpiness" when just slipping the clutch to slowly reverse or move forward...not a fast "shudder", but more like a bucking or jerkiness. Really weird.

The replacement clutch was a LuK complete kit, including flywheel, supposedly a premium model.

I guess I'm looking for answers and/or recommendations. I'm inclined to shy away from LuK at this point since this last one didn't last nearly as long as one would expect. I don't do heavy towing...the most I've pulled is a 6000-pound travel trailer about 3 times.

What's the collective think? Dual-disc clutch? Pucks? Preferred brand? Root cause of the problem if it's not just a lousy clutch kit?

You guys haven't let me down yet! Thanks in advance...

Dave

 

[Rdnck84_03]

I have found that usually when one is lunging with clutch engagement ( usually worst when trying to ease up an incline in reverse ) is usually the pilot or input shaft bearing letting the input shaft wobble around.

James

 

[unclehoser]

That makes sense. I'll have it checked out when they pull the trans. I'd still like to know how a clutch goes into slip mode after only a bit over 20K miles, though. There has to be a reason, even if it's just a lousy junk clutch kit. Good parts are hard to find these days.

 

[Rdnck84_03]

Make sure that the hydraulics are completely releasing. I had a 94 460 zf5 truck that would with each pedal push keep building pressure until it would finally start slipping.

When I would start to notice it slipping I could crawl under the truck and open the bleeder on slave cylinder and watch the arm release. I'm not sure exactly what was causing it, after about a year of fighting it I went a bought a Raybestos brand pre bled master slave and line and the problem went away.

James

 

[unclehoser]

Thanks for that. It's one more thing to check! I can't get under the truck to do anything myself, so I'll have to trust the trans shop...but they're very good and they tend to listen.