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99 C3500 6.5- need help

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347Ranger

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New to the forums..

I was sucked into fixing one of my FIL’s work trucks (by that I mean I was offered beer). It’s a 1999 Chevy 3500 2wd 6.5L diesel with a 5 speed (NV4500????) its a single cab DRW utility bed/dump bed (yes it looks like a regular utility/service body but the center is actually a dump bed) any ways previous owner put a brand new transmission, clutch, slave cylinder, and master cylinder. Still the clutch barely wanted to engage. Well after my wife’s dad removed the clutch pedal, broke out the torch and welder and made his own modifications, the clutch doesn’t engage at all. Pedal is firm, but still nothing. I am replacing the pedal assembly Saturday and see what that does, but I have bled, bled and bled the clutch. There is no air in the system, slave is good, master is good. Anything I should check? Any ideas?

Thanks
 
Yeah, homemade mods are best replaced for factory components. Get all that back to snuff first.

Pay attention to the pushrod from pedal to master,
Pedal hinge, fork, throw out bearing.

Pull the clutch and see how bad it’s burned. Smoke it in the beginning and everything else is a waste of time.

Get FIL comfortable posting on here. This site is a gold mine to keep the whole truck in top condition.
There are lots of others here with more clutch time than me so give it a day or so for best answers...
 
OE a 99 should have a concentric slave and a single mass flywheel (solid flywheel).

Do you mean the clutch won't release or engage?

For a 97 pushing the pedal to the floor should release the clutch and allow the stick to go into reverse (unsynchronized) within about 1-2 maybe 3 seconds max.
I believe all the gears on a 99 are synchronized so it should release and go into any gear almost instantly.

Being hydraulic it should self adjust and start to engage about mid pedal stroke. Being plastic master and some small components there is a bit of flexing so travel for engagement might vary a bit.
 
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Agree that taking the system back to OE is a good way to go. One other thing to possibly check is that all the components are correct as they are not completely interchangeable across the GMT-400 years. IIRC, the pedal itself is interchangeable, but the hydraulics are not. '95 was an oddball year and IIRC mostly unique to itself in terms of the hydraulics.

Toward the engagement point, (with '96+ components) that clutch will most likely want to grab near the top of the pedal travel (foot nearly off). Some like it high, most prefer it low. Seeing as the system is hydraulic, not much you can do about it.

And, Yes, the tranny is probably a NV4500 (unless the PO put in something else).
 
schiker said:
OE a 99 should have a concentric slave and a single mass flywheel (solid flywheel).

Do you mean the clutch won't release or engage?

For a 97 pushing the pedal to the floor should release the clutch and allow the stick to go into reverse (unsynchronized) within about 1-2 maybe 3 seconds max.
I believe all the gears on a 99 are synchronized so it should release and go into any gear almost instantly.

Being hydraulic it should self adjust and start to engage about mid pedal stroke. Being plastic master and some small components there is a bit of flexing so travel for engagement might vary a bit.
Click to expand...
The clutch isn’t engaging, it doesn’t want to go into any gear
 
Previous owner replaced trans and all that. We traded a boat for it. Clutch was iffy then but drivable. Didn’t hear any noises but truck also has loud exhaust so kinda hard to hear
 
I know it is not what you want to hear, but best is pull the clutch and makes sure it was installed right. Also ensuring right parts are in there. Take a ton of pics and post them here.
You can look and see if the rear main seal is leaking or not and replace while clutch is out if needed. Not real expensive while there.
 
Are you sure it’s a clutch problem and not a trans problem.

It’s been several years ago but My dads gasser 95 started to not want to go in gear after he pulled thier heavy camper several times. He talked to several people about it and finally took it to have it rebuilt.
 
Will L. said:
I know it is not what you want to hear, but best is pull the clutch and makes sure it was installed right. Also ensuring right parts are in there. Take a ton of pics and post them here.
Click to expand...

^ X-2.

Apologies if I was not clear with my last post. Make sure the parts are correct for the vehicle and its later stage within the GMT-400 lifecycle.

Over the GMT-400 lifespan, I am aware of at least 3 distinct hydraulic setups where they do not necessarily interchange well. Not trying to bad-mouth any prior work, but if somebody took a 'parts-is-parts' approach, this is one possible explanation of the current issue. Then again, maybe not, but at least we can start eliminating things which helps shift focus toward the actual issue(s).
 
Sounds to me like their is not enough travel in the slave, also I have found the near only way to fully bleed the clutch system is to bench bleed it.... remove the master cylinder, line, and slave cylinder leaving everything hooked up... place the master in a bench vise and let the slave hang down, slowly push the slave rod in and release, over and over, I have seen these systems take quite a while to get all the air out.. once no more bubbles are found leave everything hooked up and install, guaranteed to be a good petal feel...

And yes I know about the steel line, their is someone that makes braided steel lines with "push pin" fittings, what our trucks have, and adjustable petal push rods, I have it in my rig and it's much better than the factory junk...
 
I know you say you have bled it over and over, but! I have one recommendation with that. The only way I've found that works is to take a big plastic syringe from the CO-OP, fill it with brake fluid, stick it into the bottom of the clutch master with someone under the truck opening and closing bleeder. One good squirt bleeds it right out. Just a idea if nothing else works I can't read all the comments right now so sorry if this is off topic
 
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