2500 Hd Nv4500 Clutch Problem

[Dal2HS]

This is my first post here so I ask patience. Installed a new clutch kit in my 1994 C2500 with the NV4500 transmission. Also installed a new clutch fork as well as new slave and master cylinders. I have bled several bottles of fluid through, done an overnight bleed, removed the transmission 3 additional times to check things. I can hear the throwout bearing moving the springs, but the clutch won't fully engage. The transmission shifts easily into gears when the engine is off. I did have the flywheel resurfaced and I believe it has been resurfaced once before. A mechanic this evening suggested that the flywheel needs to be shimmed to for the clutch to engage properly or I just need to get a new flywheel. I'm completely at my wits end with this thing... the clutch disk was completely torn apart when I got it...so I'm hoping it's not the shaft bent.

I would appreciate any input on what I should do with it. I'm going to check on ordering a new flywheel as I believe I have exhausted every other possibility.

On others of these I've driven, the clutch has been pretty stiff. This one seems really soft...

[jf781]

I went through this kind of fun with my 95 f150 (and the slave just started leaking agian and in ford's ingenuity they put the slave inside the bell housing around the input shaft which means I get to pull the tranny /offrant)

 

If the flywheel has been resurfaced too much you wont have any troubles with the clutch engaging. You will have trouble with it disengaging cause there fork only moves so far when you depress the clutch pedal and if the flywheel is too thin the fork would have to travel farther then normal to completely disengage the clutch. (My word sucks but just think of it as flywheel, clutch, and pressure plate has moved towards the engine while your fork has stayed stationary).

 

If you just mean to say disengage then disregard this statement. I would check to see if someone has the specs for free play between the pressure plate and fork and see if you within that range. That will let you know if your wasting your money on a flywheel or if there is something else you need to look into.

 

Keep us updated - it took me a long time to figure out my problem so I learned a few things in the process I can hopefully help you with.

[Dal2HS]

That must have been what I meant to say... When the clutch is depressed, then essentially nothing happens. You can hear it pressing the springs, but it still won't go into gear. It will slide into first and second, but will drive off with the clutch all the way to the floor.

[REV353]

If you shim the flywheel, that will mess with your starters engagement. I am not familiar with yours, butt, is there a push rod that goes between the slave cylinder and the fork?, I would add something between your slave cylinder and fork, this will give your fork more travel and allow it to disengage more. When they resurface, they only take off about the thickness of a sheet of paper.

 

Hope this helps. Did you check the parts and make 150% they were the same?

[Dal2HS]

There is a push rod. I have changed out the master cylinder twice and the slave 3 times to make sure I was getting good ones. I would think the line is leaking but I'm not getting any more air. We tried prying the arm further to see if it would engage. No such luck plus a smashed finger on my part. The starter on this truck already has a shim...so I guess it could get another. I'm beginning to think I got a bad clutch kit. I didn't replace the pilot bushing but that would just make noise. The clutch kit came from Auto Zone (I don't want to put a lot into this truck until I make sure it's reliable) but should at LEAST work for a while.

[jf781]

That could be another problem is the autozone parts are exactly the best quality - not saying they all suck but I had problems when I did mine to where the slave was too long and wouldn't allow the the clutch to fully engage (again different setup then yours). Ended up going with Barron's which is local store but Napa and Oriellys are better parts then autozone.

 

Does anyone have the spec for free play between the clutch fork and pressure plate? what the fork's travel distance should be? If we can find those too things we can make sure that the hydraulics are working properly and that the flywheel should be within spec. This will at least help us narrow down whats going on.

[Dal2HS]

I got two different slaves from Advance Auto and one from Oreilly's. I'm more thinking it's internal as everything seems to be ok with the hydraulics. I left it with the clutch depressed overnight to see if any more air came out (technique I've seen on several sites). I'm going to the dealer in a bit then to talk to a couple of mechanics. If I have no luck it's going to the shop.

[2500hdee]

I have a NV4500 5 spd in my '01 2500HD with 205K and I'm on my 3rd slave cylinder and original clutch. Following this thread.........

[Dal2HS]

So it seems that the flywheel was ground down past the limit. There was over 1/8 of an inch difference between the old one and the new one. That, combined with a new kit from Advance, and it works beautifully. The syncro on 3rd is a little shaky, but hey...a little double clutching never hurt anyone. My 81 year old mother still does it sometimes out of habit.

 

Now to figure out brakes...I guess that's a NEW post. Thanks for your suggestions!

[jf781]

Glad ya got it fixed and thanks for updating us on what it was!