NV4500 Tranny Trouble

[6.5 Detroit Diesel]

Okay, seems like one thing after another right now. I have my Dad's 95'
6.5TD needing a new TC, doing a tranny swap on my brothers Jimmy, (700-R4), and now my own truck tranny is acting up. Here are the symptoms.

Goes into gear okay when engine not running.
When running, have to basically jam it into Lo or first gear. When driving won't downshift unless you really shove it. Won't drop into second at all.
I used to always start off in 1st. Now, unless I start in lo, it will crowhop a bit as soon as the clutch engages. Going through a drive-thru, it wouldn't come out of gear at first. When the clutch is in and it is acting sticky, I hear what sounds like a whirring noise. Reminds me of the noise a forklifts hydraulics make when the load is to heavy to lift.

The clutch reservoir has plenty of fluid, but the level barely changes at all when the clutch is pushed in.
The clutch, (and flywheel), are still rather new. Just over 20,000 miles on them. The truck has never been used for loads over 8,0000 lbs. Any ideas as to what this could be?
Aggravating to say the least as I also have roofing jobs to get to!
Thanks
Ben

[a5150nut]

Have you checked the trans to bell housing bolts to see if they are getting loose?

Other than that it could be a failin master or slave cylinder. Did you bleed the slave? Allen screw on top just ahead of where the line comes in.

[6.5 Detroit Diesel]

I will be checking it out. Thanks! Any other suggestions.

[6.5 Detroit Diesel]

Okay, so I disconnected the hose that runs up to the reservoir and plugged the bottom of the reservoir. I then filled up the reservoir with new fluid and tried the clutch. Basically no resistance, the clutch goes straight to the floor. So I am figuring that that is the problem, the master clutch cylinder. New one here and ready to go in! Also got a new slave cylinder as well as I am sure the old one needs to be replaced anyways. Hope that is the problem, though I can't see what else it could be!

[Busted]

dood, you shoulda called me up--I've got a brand spanking GM master cylinder in the box that I found in the back of that red and black truck I parted out . . . oh well.

Don't wreck your tranny :-)

[6.5 Detroit Diesel]

Nice dood. I had known back when I was out there that this was going to happen, we could have avoided it, eh? Oh well, sure you will find use in your tranny swaps. I gotta get the truck back together tomorrow though.

[6.5 Detroit Diesel]

New master clutch in. Put half a liter of fluid through trying to bleed out the stupid line. Still won't go in when running. If you jam it in, sounds like it is making light contact with the plates. Clutch won't stiffen up. Removed the inspection bolt and found that the fork moves around half an inch with pedal fully engaged. ?????????

[a5150nut]

Could be the pivot ball has gone away at the clutch fork. I've seen them wear clear through the fork. Sounds like time to pull the trans and check deeper. When moving the clutch line don't put any stress on it. DISCONECT AT BOTH ENDS before moving things around.

[6.5 Detroit Diesel]

Yea, sounds like it is time to move in. Did some research and found some people have had the fork actually bend after a while. Not sure how much of a possibility this could be though.

[6.5 Detroit Diesel]

Pulled the trans yesterday. Was to dark to see much so had to wait until today to get in close. The bellhousing is still attached to the block. I removed the throwout fork, bearing, and stud. The fork is cracked around the stud hole. The bearing is rather noisy. And the stud is worn down around the contact point. Also, there is apparently a keeper and a seat that go on the end of the stud that were no where in site. Anyone ever seen this before? Would the worn stud and missing seat cause it not to go into gear? I have pics.....

[HH]

YES. Replace the ball & fork, and may as well do the TB too. There is a zerk fitting on the bellhousing to grease that part, most people miss it. You will notice a huge difference.

[6.5 Detroit Diesel]

Well all parts are in. Seems to have done the trick. As for that grease fitting, I couldn't find it on the bellhousing. Is it covered by something? The TB is something that I want to keep well greased in the future.

[HH]

It for greasing the pivot ball. Should be right below where the pivot ball bolts in, IIRC, been a while since I greased mine.

[Turbo Al]

The fork and pivot need to be repaced as a unit and if there is any wear (sounds like you have a lot) on the pivot. These things usally last about 100,000 miles so you should be replacing them every time you do a clutch -- on the 1993 there is actually a grease fitting hiding in there as well.

1993 style outside slave cyl WARNING: DO NOT over tighten the bleed screw on the slave you will crack the housing. First take it out look at it and you will see that it is tappered to fit the hole so no great amount of torque is needed to seat it. Yes I broke the first one I did LOL.

OPPs guess I should have read page 2 before I posted -- yup still mind numbing drugs.

[trbankii]

Is it possible and/or recommended to update to the internal slave cylinder? I just really don't feel good about that plastic slave sitting there waiting to get hung up on a rock while off-road...

[Turbo Al]

I don't see why not. I have not had a later model NV4500 apart so don't know what is involved. On the bright side The under carraige of my 1993 looks like WW111 and have never hit the slave in years of harsh use hunting.
Al

[trbankii]

I do a certain amount of "rockcrawling" that just seems to be begging for one to hit the slave...

I figure that if I'm in there and replacing clutch, fork, pivot, etc, etc I might as well upgrade if possible... Suppose it would be a different master cylinder as well?

[6.5 Detroit Diesel]

Didn't know you could get an internal setup. A little late this time as I already have a new slave cylinder, but will keep in mind for next time.

[trbankii]

Damn... Knew that this project was coming up for me but had hoped that it would last a little longer. Driving home today I went to downshift and the clutch pedal went to the floor without disengaging... It had been getting harder to shift lately as well - pretty much as you were describing things at the beginning of the thread...

History: clutch line burst when I first went to look at the truck, seller replaced it; last summer the slave cylinder broke off where the clutch line connects to it; now this...

Knew I should have gone through and replaced everything at the beginning of the troubles, but last year was insane and I kept telling myself I'd patch things up to just get through the current crisis - which turned into the next crisis, and the next, and the next...

Sorry... Just venting...

[trbankii]

Question looking at this page: http://www.rockauto.com/catalog/x,ca...,parttype,1993

Of the last four ACDelco options I'm reading it as the first of the four is the clutch kit for the dual-mass flywheel, the second is if a single mass flywheel was installed by the dealer previously, the third is the dual-mass kit from the first one with the flywheel included, and the fourth is the single-mass kit from the second one with the flywheel included.

Based on the prices, I'm guessing that is correct but am I missing anything?

Have to pull the inspection plate tomorrow to see what shape things are in and what flywheel I have - although I am pretty much guessing it is the original dual-mass one.