clutch failure x3?

[otisd85]

bump for any new ideas, am i the only one to repeatedly tear out the springs? i am having the nv4500 rebuilt this time, but it would be nice to know if im doing something else wrong before i put it back together again.

thanks in advance

 

[Shadetreemechanic]

I bet having the tranny rebuilt will solve your problem. Your pilot bushing should not be wearing like that. It sounds like somthing has gone south in the tranny and is shaking your disk apart.
Good luck with it.

 

[south bend clutch]

i replace the pilot every time with a new oil impregnated brass bushing, and it seems to be wallerd out every time. what might cause it to be off centered? there are 2 dowels in the back of the block that fit nice and snug in the trans bellhousing. the mating surfaces between the block and bell are clean and smooth. what else could make it off centered?

i have 2 cummins now, one complete donor 95 dodge auto 4x4, and a 190 horse out of a 96 school bus, but now i think instead of doing a cummins swap in this truck, im going to do a full off frame restoration on another truck, with a cummins of course. when thats done ill drop a cummins in this truck, that way im not without a truck during the swap, i can take my time, buy parts as money permits, and good deals come along. (now im just without a truck during the multiple clutch replacements, and this time probably a trans rebuild)

chvycmnslvr68 its too bad your so far away, i would be interested in your dually bed, and your front end. i think i seen your build thread awhile back, looks sweet. i like the way big rims look, ive just never been a fan of the price of the rims, and then how much more expensive it makes the tires.

I feel the problem is the brass bushing you are using. We tried them back in the early 90's with terrible results. Bore the flywheel out and put a ball bearing in. PB 6303 2RS will do the trick but pay the extra and buy a high quality bearing.

Peter

 

[otisd85]

I feel the problem is the brass bushing you are using. We tried them back in the early 90's with terrible results. Bore the flywheel out and put a ball bearing in. PB 6303 2RS will do the trick but pay the extra and buy a high quality bearing.

Peter

i love the idea of a ball bearing, but in a chevy the pilot bushing is in the crankshaft, a ball bearing would require removing the crank and having it machined. wouldnt it?

every 4 speed sm465 i have pulled, and every one i installed a brass bushing has come out and thats what i put back in. never noticed a problem until now.

 

[otisd85]

i guess i shouldnt say ""in a chevy" because i dont know about the duramax with a zf6, bun in a 6.2L detroit the bushing is in the crank.

 

[otisd85]

i droped off my trany this morning to be rebuilt, ill update when i find out more.

 

[chvycmnslvr68]

Is your bell housing cracked or has it ever been welded ... Is there any signs that anything has ever been run loose and made a wear mark .. if so it will cause a misalignment and that will cause the problem your having ... I had a '79 chevy that kept eating clutches and it turned out that the bell housing had been welded and they did a real good job grinding things down and you couldn't even tell where it was welded but it was warped ... I replaced the bell housing and solved the problem ...
As far as the pilot bearing goes ... the brass one is fine .. the only time that the shaft is turning in the bearing is when you are sitting at a stop and holding the clutch down ... the rest of the time it all turns together ...

 

[otisd85]

ive looked at the bell, but i guess i should clean it up and take a closer look at it. thats a good idea, thanks. about the pilot, thats the impression i was under, and im not in the habit of sitting there with the clutch pushed in.

 

[chvycmnslvr68]

well good luck .... by the way I have some tips for you when you get ready to do the cummins conversion ... I have the charge air cooler from an '02 dodge in mine and it fit perfect ... if you use the lower radiator hose from the '93 dodge with the factory 454 or 6.2 diesel radiator it hooks right up ... and the air cooler fits right in front of it and that big wide four core radiator is big enough that you cant get it hot no matter how hard you work it ...

 

[otisd85]

the info about the 02 ic is great, hopefully i can use that info sooner than later.

here are some pics of the most recent clutch failure, they are also typical of all the previous failures. the pics demonstrate how it was when i took it out of the truck.

1. clutch on pressure plate
2. clutch on ground, hub no longer attached
3. hub still on pressure plate
4. hub off pressure plate missing most of the springs
5. majority of the springs that are supposed to be in the hub still in the pressure plate.
6. damage to the flywheel from the springs not staying where they belong.

i may be mistaken, but im pretty sure how all this came apart isn't how this particular pile of parts went together.

 

[tanman_2006]

A worn input shaft is ******* NV4500's I have both of mine out for rebuilds now and found my 93 to have a cracked bell. I am using brass synchros from blumenthals (in OKC), reusing all of my speed bearing (bearings inside of the gears themselves), and replacing all my main shaft bearings. So far I just have my 94 apart and found the synchro sliders to be worn (300K miles of hauling hay and equip will do that i guess) and blumenthals has the hard parts too. If you call Blumenthals ask for Mary iirc and she will educate you.

I'm looking for custom clutches now, I am in the hunt for 300HP but would be happy with 250 on the tow rigs.

My 00 crew cab is going to get a fully built "Mini Max": Dmax Inner cooler, Rad, Fan (and Fan shroud if needed), VVT Turbo from my 06 LBZ (going bigger on the 06 w/ efi live), center mount turbo with up pipes and a custom lower intake to mirror a dmax, and triple disk converter. If i dont get 300hp with that i'm gonna throw in the towel lol

 

[otisd85]

on a cast iron bell housing you could check for cracks by magna fluxing it, my bell is cast aluminum so that wont work. i cleaned up the bell all nice and pretty, there are some places i cant tell for sure if they are casting lines, or cracks?

is there a good way to test aluminum for cracks?

thanks, otis

 

[otisd85]

upon closer inspection, it seems my clutch fork is worn and has some small cracks in the pivot ball area, and the pivot ball is worn also. the local parts stores have the fork, but it looks like i have to order the pivot ball from the stealership.

 

[JPalmer81]

Any updates? getting ready to swap a 465 behind my 6.2 diesel and don't want to go through what you have been going through. Hoping you finally got it to work.