Clutch options

austin92

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Have an 83 6.9 with a zf5 and I need a new clutch. Plan on a turbo soon and want a clutch that can hold. I've burnt this stock replacement 4 times now and I'm over it. First of all will a clutch kit for an 88 work on my 6.9/zf? Considering south bends 425hp/850ft lb for 800$ (includes smf) and valair's 350hp/800ft lb for 300$ with no fly wheel. Would like to do a new fly wheel either way and south bend has an all cast iron tob. Also heard that psd flywheels bolt to our cranks so we can run 13" clutches. I just want to pull the tranny once and b done. Willing to spend good money to do it right the first time. What have you guys done?
 

towcat

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Have an 83 6.9 with a zf5 and I need a new clutch. Plan on a turbo soon and want a clutch that can hold. I've burnt this stock replacement 4 times now and I'm over it. First of all will a clutch kit for an 88 work on my 6.9/zf? Considering south bends 425hp/850ft lb for 800$ (includes smf) and valair's 350hp/800ft lb for 300$ with no fly wheel. Would like to do a new fly wheel either way and south bend has an all cast iron tob. Also heard that psd flywheels bolt to our cranks so we can run 13" clutches. I just want to pull the tranny once and b done. Willing to spend good money to do it right the first time. What have you guys done?
for starters, PSD flywheels do not bolt onto IDI cranks. the bolt pattern is a night and day difference. outside of the OEM turbo motor, the flywheels, on the whole, are neutral balanced to the motor. what that means, is any t-19 or ZF5 IDI non-oem turbo flywheel will bolt onto the IDI crank and will not alter the rotational balance. there are some out there who will spin balance the whole rotational mass as one. you are now restricted to that one flywheel. only you can determine if it is worth it or not.
personally, if you are blowing up clutches this frequently, you need to look in the mirror as ask yourself what are you doing wrong. I've had the most basic 12" oem clutch on17-21k/lbs gross loads and they lived for at least 4-5years. If you look hard enough, Valeo, LUK and SBC offers the 13" option with the appropriate flywheel. Also, do some reading about "camming" on the clutch covers, more than one member here has found that to be a problem with premature death related to the TOB and cover fingers.
 

austin92

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I'm not doing anything "wrong". I've been driving manuals for 10 years and I have yet to "blow up" a clutch. But last night I tried to sled pull, I've hooked chains with a 460 automatic, and helped a buddy pull start a full sized John deer tractor. Every time I was less than pleased with the clutch. I really don't want the guys that have 4.10s and a turbo that never break 1800rpms towing 4000 lbs at 50mph chiming in because that's nothing like how I use my truck. Mine is a 3.07 rear gear, and I push my truck to its limits whether I'm playing or working it with it. I just want a clutch that actually grabs


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franklin2

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I guess you know with a 3.07 gear you are demanding a lot more from the clutch, the transmission, and the driveshaft/u-joints. If you do get the clutch to grab, which one of the other components is going to be next?

If you changed to a higher number ratio in the rearend, your driveline spins faster and can be much lighter duty and has a easier time of it. That's why heavy equipment uses planetary gearboxes in the hubs, they can run much smaller axle shafts and gearing in the driveline.

Sounds like a underdrive unit would work well for you. That still would not relieve the u-joints though.
 

jwalterus

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I'm not doing anything "wrong". I've been driving manuals for 10 years and I have yet to "blow up" a clutch. But last night I tried to sled pull, I've hooked chains with a 460 automatic, and helped a buddy pull start a full sized John deer tractor. Every time I was less than pleased with the clutch. I really don't want the guys that have 4.10s and a turbo that never break 1800rpms towing 4000 lbs at 50mph chiming in because that's nothing like how I use my truck. Mine is a 3.07 rear gear, and I push my truck to its limits whether I'm playing or working it with it. I just want a clutch that actually grabs

OK, normally I'd just stay away from this one because of the attitude coming across in that post, but I'm a little irritable already this morning.
First off, 10 years is NOTHING. Hell, by the time I was 20 I could have claimed that, and every time I was behind the wheel underage it was because I was towing to help my dad. His old truck was an anemic '82 f100, 2wd, v6, 3 on the tree, get on a boat ramp with a 3k tri-hull and a 50% grade and I was in the driver's seat because the truck couldn't hold it (parking brake didn't work), half the time I'd drive home on the dirt roads because he was tired. When I was 16 I was driving a 40' straight truck ('80 IH) for a moving company because even the older guys working there couldn't drive it.
Second, if you truly have a 3.07 rear, what the *bleep* are you doing trying to sled pull at all? Did you put in the 3.07 rear? Put the factory 3.55 or 4.10 back in, and if your truck actually came with a 3.07 rear, get rid of it, these engines are anemic enough trying to work them with a 3.55 rear, I can't imagine it being anything but hopeless with a 3.07 behind it, I'd think you were pushing it to the limit just trying to haul itself down the road. LOL
Third, check your attitude. I tow with a 3.55 rear, 4-speed, and N/A engine, and more than once I've had enough weight behind my truck that I've had to start in 4-low on flat paved ground and go to high range once I work my way through the gears in low range (try an IH 3388 on a trailer that won't cry from the weight), but it's nice to be able to put 3-4k behind the truck and turn 2700 at 70 without OD, someday I'll drop in a zf and go to 4.10s, might even turbo my truck, but until that day, I'm fine with what my truck has.
Fourth, AFAIK, the south bend clutches are still a LUK kit with a re-worked pressure plate, they run the same friction plate. I've had a napa special in my truck for a few years now, it's easy to claim the clutch can handle 425hp when it's for an engine that's not capable of making that. LOL
Fifth, if you haven't grenaded a clutch, you haven't pushed a truck to the limit. I've had friction plates shatter, TOBs come apart, and pressure plates blow off the fingers. Not to mention the autos I've burnt up and engines that have spewed their guts all over the road.
Finally, how about a little info on your truck in your sig?
 

austin92

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Jesus.... I joined here because everyone seemed cool. I ask for advice on clutch kit holding abilities and apparently now I know nothing about how to drive? As for the comment about putting factory 3.55-3.73s "back in", the truck has a factory Dana 61 with factory 3.07s but I'm sure I'll get told I'm stupid somehow for that too... Oh, and so what I tried to sled pull, it's fun, I tried, clutch slipped? I'd like to apologize for having 10 years experience on a manual at 24 years old, clearly not up to your standards, my bad. Sounds like from the stuff you've blown up I'm not the one that needs criticized for how I use my vehicle. I've tried using this site on tapatalk, and mobile version, even my girlfriends computer, I can't figure out how to set up a signature


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Shawn MacAnanny

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Signatures don't post on mobile anyway. I met a guy the other day who'd been tig welding for 12 years. Looked at me like I was stupid when I asked where his foot pedal was.

I purchased the southbend clutch for the idi turbo engine I'm having rebuilt. Doesn't matter how much clamping force or what material you have if you are over heating the surfaces. Certainly 4 clutches is too many. Are you sure you don't have a leaking transmission input seal or rear main?
 

79jasper

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For a stock idi clutch, sled pulling is just asking for trouble.
I believe it's greg_5.0 that's trying to use a psd clutch, but will take machining to work.
And yeah, get rid of those 3.07's.
I would also assume you're running bigger tires?

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austin92

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I guess you know with a 3.07 gear you are demanding a lot more from the clutch, the transmission, and the driveshaft/u-joints. If you do get the clutch to grab, which one of the other components is going to be next?

If you changed to a higher number ratio in the rearend, your driveline spins faster and can be much lighter duty and has a easier time of it. That's why heavy equipment uses planetary gearboxes in the hubs, they can run much smaller axle shafts and gearing in the driveline.

Sounds like a underdrive unit would work well for you. That still would not relieve the u-joints though.

Thanks for trying to offer help man. I do know that changing gears will alleviate driveline stress and I have been keeping an eye out for a 4.10LS 10.25/10.5/dana80. I have considered an under drive but that cost lots of money lol. Lots of projects I'd like to do to my truck but right now I'm after a clutch


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austin92

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Signatures don't post on mobile anyway. I met a guy the other day who'd been tig welding for 12 years. Looked at me like I was stupid when I asked where his foot pedal was.

I purchased the southbend clutch for the idi turbo engine I'm having rebuilt. Doesn't matter how much clamping force or what material you have if you are over heating the surfaces. Certainly 4 clutches is too many. Are you sure you don't have a leaking transmission input seal or rear main?

I'm not saying I've burnt up 4 separate clutches, I mean there's been 4 times now on this one clutch that I've been all the way off the clutch pedal and the trans input shaft had no intentions of matching engine rpms lol


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austin92

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For a stock idi clutch, sled pulling is just asking for trouble.
I believe it's greg_5.0 that's trying to use a psd clutch, but will take machining to work.
And yeah, get rid of those 3.07's.
I would also assume you're running bigger tires?

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No, stock height running 245/75/16 bfg all terrains


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riotwarrior

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Hey if he wants 3.07's great....super for milage....just DON'T PULL much of anything.

Mqybe the smoked clutch is telling you something? GEARING perhaps?

Ifnyou want to keepnit as is...do that....no skin in the ae here or from anyone else. Just dont expect much in the way of capabklity from the truck outside of light duty towing and such.

JM7.3CW Eh!
 

franklin2

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Thanks for trying to offer help man. I do know that changing gears will alleviate driveline stress and I have been keeping an eye out for a 4.10LS 10.25/10.5/dana80. I have considered an under drive but that cost lots of money lol. Lots of projects I'd like to do to my truck but right now I'm after a clutch


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Possibly a cheap way to go and keep your 3.07 gearing is swap in a 4x4 tranny with the transfer case. If you want to pull a sled, put the transfer case in low range and have at it. Then put it back in high range and drive home. The transfer case doesn't care that it does not have a front axle and driveshaft hooked to it.
 
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