So this problem has been eating away at me for a while now. Ever since I bought this truck almost 2 years ago, it has always had a hard shift problem. It almost feels like the clutch doesn't release fully right away. I figured it was the stock hydro's going out. I replaced them with the valair HD set from DAP. It definitely helped the problem but it hasn't completely gone away. I thought at first maybe the tranny is just starting to wear out being it has over 200k on it, but it feels exactly the same in every gear. I tried adjusting the clutch pedal out farther so it gets more travel and pushes the clutch more. Still feels like the clutch isn't releasing all the way at first. The truck doesn't try to creep forward on me or anything, I just have to hold the clutch in for about 2-3 seconds in between shifts if I don't want to "catch" the next gear hard. Without pulling the tranny, I am not sure what else I can do. Would a worn out pilot bearing/bushing cause this? The clutch doesn't slip or anything yet. I just don't want to wear my tranny out prematurely or whatever. I even replaced the fluid with no change in behavior. Sorry for the novel guys, just don't know what to do.

One other thing with grinding tables is that they need constant maintenance to keep the table and stones true as well, we checked the table over weekly and made adjustments and cleaned and changed the fluid as needed. When I worked at Inland Truck Parts and service, every flywheel got checked with a dial indicator for run out on the surface and diameter before it got removed from the table to make sure the table wasn't getting out of true.Some guys got in a hurry and it bit them in the but by not checking.

Mine was driveable but there was no finessing the clutch. When it it came time to go you just had to let it out quickly or it would really be jerky. It shifted fine, launches were rough if you eased it out. It is still jerky with the RV in tow at low speeds in the rv park but is manageable.

That is just the nature of some ceramic or metallic clutches no matter what. If it is an organic or fiber clutch and it is grabby there is something wrong, they at no point should ever be jumpy/jerky.

One place where I worked we had an International with a ceramic clutch. Only the boss (owner), me and one other guy drove that tractor and we all called it the 'rabbit'. The clutch was either fully released or fully engaged. Makes it a little tough to get going smoothly.

My OFE; even with almost 130k on her, still doesn't like to be "feathered". Either engage it, or disengage it!!!

My Con-OFE was the same way, after 20K it didn't get any better so I yanked it out and went with a 1947-OK-HD. Both got new flywheels. I'd like a clutch that will hold but not jerk like crazy and am hesitant to go with a dual disk on my 6 speed because of shifting/noise issues.

Did the newer clutch solve your problem? Mine did get a lot better, but is still jerky with the fifth wheel on launch and low speed maneuvering while parking. That is unless I can just let the clutch all the way out.

Ok guys. Update!! I am ordering this clutch today. http://www.dieselautopower.com/product-p/valair%20org-fslash-org%20nmu70279-01.htm

 

I am getting with a buddy and we are going to change it out in an upcoming weekend. My question to you guys, what should I be prepared for once I open this thing up? What should I do while I am in there? I have heard of people with problems with the clutch fork, is that something I should be worried about?

 

I am just trying to make this job go as smoothly as possible and save myself some money by doing it myself.

Are going to get a new flywheel of have the old one resurfaced? Check your seals while its open, engine and tranny. Even f they are not leaking it would be good to replace them if you have high mileage. That tranny weighs around 400# so be careful not to drop it on anyone. You should be able to rent a tranny jack some where. I did mine with a floor jack. I bolted a steel plate in place of the cup and strapped the tranny to that. It worked but still worried me while it was up in the air. I was only replacing the tranny since I lost 4th gear in mine, the clutch was only a year old.

I resurface flywheels at my store so I can take care of that. My buddy works for the county as a truck mechanic and is going to let me use the county's shop   so I should have all the jacks, lifts, tools that I need. Is it hard to do the seals? I would assume the tranny one just pops out and you pop a new one in but what about the crank?

When my ECM went the second time, I had it at a shop and already had the clutch(same one you have)so I had him install it while it was sitting. He did the rear main for me. Cant imagine it is that hard to do. I dont remember any problems with the tranny seals. 

 

Sure sounds like you have a great set up for the install. Much better than a piece of 3/4 plywood in the gravel driveway. I did have plenty of help though.

Look here for the instructions for how to replace the rear main seal on your truck: http://dieseltrucksite.com/showthread.php?t=266

Ok, 'nother update. Some things came up for my buddy at the county shop and wont be able to help for a few weeks. I need to take the truck into the shop anyway to get the oil change, chassis lube, tire rotation anyway before my big trip to Colorado. I am just going to have the shop take care of the clutch job and that way it gets done before my trip.

 

Are there any specific break-in procedures for the new clutch? Maybe I should just call DAP and see what they say?

I'd give it ~500 miles to seat/break in. LOL, I remember the good ol days of putting the front bumper against a tree, and burn the snot out of it to 'speed' up the process!

Meaning: try to keep engine rpm low as possible/matched to trans input as possible, NO high speed dumping of clutch, jackrabbit starts, pulling contests, drag races.. geez, I sound like my Dad!

This is just for the engage/disengage part.... after it's hooked up, drive like ya stole it.

your question about the fork, I was forced to 'let' the dealer change out our 6 speed about 5 yrs. ago. (don't criticize... I didn't have a choice!) I supplied them with my own rebuilt trans, They were only used for the R and R part. anyway, less than a year later, the clutch was totally gone, (wouldn't release) broken diaphragm springs, the fork was all bunged up.. My trans guy (independent) said the fork may not have been installed on the right side of the fulcrum.. or some little retaining clip? Or it may have worn out totally! Now sure would be the time to inspect/replace!!

Edited February 5, 201411 yr by rancherman

Ok guys. Got the clutch changed out and what a difference!!!! I dont know what clutch was in it before but this new valair is almost as easy to disengage as my wife's honda was! The old one was tougher to push in than my dads big rigs. It shifts perfectly now, almost no delay between shifts and it grabs quick. It does chatter a little bit but just dont slip it and you will be good.

 

Now, after I picked it up from the shop I noticed that in the higher gears (4,5,6) if I try to accelerate from about 1100-1300 rpms, there is a hard fast vibration coming from the mid to rear of the truck. It goes away as soon as you get up above about 1600 rpms. It does not do if you are accelerating slowly at all. You can hear and feel the vibration.

 

I had to get right back to work yesterday otherwise I would have taken it right back. I will crawl around underneath tonight and see if I can find anything loose but does anything come to mind for anyone?? I was kind of thinking maybe the carrier bearing is still loose or something like that.

That's the clutch holding the power.  What clutch did you go with again???

clutch sipping, chattering, especially if you are into hard in the higher gears? I believe we have the same clutch( Valair with organic facings) and I never notice mine do that. It does however chatter on launch.

Edited February 13, 201411 yr by dripley

I did get the valair single disc with organic lining. It was a 3400 lb pressure plate and should be good for 400hp. I never thought about it maybe the clutch slipping. It doesnt rev up or anything, it just has a fast vibration for a few seconds then it goes away. I havent gotten to hard on it yet because I heard you were supposed to use low power to break in the new clutch for the first couple hundred miles.

 

Should I get on it and see if it will fully slip maybe? It does chatter on take off a little bit but it clears up right away.

I think I would talk to the shop that installed it and whoever you bought it from and get their opinions before you stomp all the power thru it. The way I read your post i thought you were on it hard since it did not do it when accelerating slowly.

I should have explained it better. It does not do it accelerating slowly but maybe about 50% throttle is when I feel it good. I guess it could be called moderate acceleration.