driving home from work the truck suddenly would not shift, it felt like the clutch was not completely disengaging. The only way I could get it home was to start it in gear but the truck was obviously lunging, did that once and limped it home in 2nd down back roads. Master was clearly leaking inside the truck but not a lot. Slave was dry as a bone, put all new hydraulics in it, it feels like I have more on the pedal but still the same problem. Thoughts? Do I have to pump it a thousand times to bleed it, it's one of those pre bled systems.

This happened to me once before a couple weeks ago and then it just magically went away after messing with it for a minute. I'm thinking maybe my fingers on the clutch are gone or throw out bearing quit but ive had no chatter, slipping or whining. I can shift through the gears with it off or running if my t case is in neutral.

 

[QUOTE=Elvis40;15092619]Do I have to pump it a thousand times to bleed it, it's one of those pre bled systems.[quote]

Yep, but maybe only a couple of hundred. Dry is dry and getting air out will build left leg muscle. Enjoy.

 

Just put on a couple hundred more pumps and still the same.

 

You may have loose lining on the clutch disc itself or a pressure plate that is bad and not releasing pressure on the disc even though the master/ slave cylinder is working.

 

You said "pre bled" system but if dry, I'd get some help and manually bleed off like your brakes.

 

I did a clutch job on a Ford SD few years back, same exp as you have. I didn't normally work on trucks but the kid was a college student and had inherited the truck from his dad who had passed away.

What I remeber was when I finished it still did not work, so I bled it again and again, lost track but I finally got a quart thru the master/slave and it started working. It might have been a bubble in or??? I also bled both front wheels while I was at it, not sure if that was a contributor to the solution or not...

 

Well I opened it up and didn't find what I expected. There where's ton of pieces in the bell housing ( I had been hearing them periodically for the last few weeks but had convinced myself it was something else) and everything else "looks" fine. The pieces look like clutch springs although the clutch disc is one unit. Flywheel surface spins seperately than the part with the teeth on it, this whole thing looks very wierd to me, is definitely not an np435.

 

If you have pieces in the bell housing you may have a blown clutch. If there is air in the hydraulics system attach a hose from the slave to the master in a loop and continue to pump so the air flushes out.

 

Update: The clutch is one solid piece and looks fine. The pressure plate, shift fork and throw out are all there and look fine. The pieces scattered around are out of the flywheel ( dual mass).

I understand that there's been flywheel spring pieces flying around for a while but I don't think that can account for a clutch that doesn't disengage and doesn't make noise. I hope there's nothing else wrong.

The only thing I can think of is a piece got stuck on the backside of the PP and wouldn't allow it to back up, forcing the clutch to stay engaged. It clearly didn't get stuck between the plates because there's no scratching or chunks removed from either of the plates or clutch disc. I don't know much about these zf 6's and I don't really know anyone that does.

If I can upload pics I will post

 

Flywheel with all it's missing springs





These are the three things i assumed would be the culprits, nothing here seems wrong. Which worries me





everything in the pan came out of the bellhousing area





Clearly parts have been flying around. little plastic fork pivot piece doesn't look broken either. the sleeve around the input shaft looks worn








Pieces hiding up in the cavities, chain at the top is the trans jack safety chain, visible through the vent holes at the top of the casing

 

What was the final cure for you? Mine wasn't disengaging far enough and found the eye on linkage to master cylinder wore almost through as was the pivot pin. Bought a new prebled from Rock Auto and it is even worse now. I replaced the pin with an allen head shoulder bolt. The RockAuto number is PS0713 pre-filled Mine is a 95 F 250 4X4 that switched out the tranny from a 92 F 250 4X4.