SBC DD 3850, 6 months, ~7k, no hooks

[getblown5.9]

I've loved my SBC DD since the first time i drove it. But am i being to hard on it/expecting too much? this is with no hooks and only some 3rd gear street launches. Its never slipped tho, once its locked... ITS LOCKED. it holds... but when i launch etc am i slipping it too much?



Flywheel

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inner disk

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Floater Plate

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Outter disk

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Pressure Plate

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[Got Smoke?]

Just my personal opinion that looks like an extreme amount of slippage.

 

[RobertP]

man TJ you really got that thing hot. wow. i know when i went for a ride with you it held great.



Robert

 

[getblown5.9]

Just my personal opinion that looks like an extreme amount of slippage.

20-25 3rd gear launches on the street, and 1 4th gear launch... i only slip it for about 3-4 seconds max to get moving then it grabs and away the truck goes.



Looks like i need more clutch or i should give up on the 6spd. im rebuilding my NV5600 for the second time now... and i haven't hooked to a sled yet

 

[jwilliams3]

It looks like alot of intentional slippage to me.



If you are fascinated with the street scene I would recommend getting an auto.

 

[TJSHOTROD]

Read my Sig.

 

[Vaughn MacKenzie]

20-25 3rd gear launches on the street, and 1 4th gear launch... i only slip it for about 3-4 seconds max to get moving then it grabs and away the truck goes.

No wonder it looks like that . . . 3-4 seconds of slipping is an eternity



Just curious but why the 3rd gear launches? Starting off in 2nd should save the clutch.

 

[JasonCzerak]

No wonder it looks like that . . . 3-4 seconds of slipping is an eternity



Just curious but why the 3rd gear launches? Starting off in 2nd should save the clutch.

Drag racing the NV5600 it's a crap shoot to choose between 2nd or 3rd. 2nd is a bit to short, 3rd is a bit to long of a ratio. He's compassionating with a massive clutch to drag out 3rd and in the end that's the best way.



Plus, it's not easy grabbing 3rd from second with out falling on your face. My truck is almost to the point of HP that it's a split second from engagement to shift. you cant tell the truck isn't getting as much power to the road as it could on a hole shot.



I've tried 3rd gear launches with the ConFE, all I did was finish breaking in the clutch an seat her.



So, ideally you want to get a smaller tire or greater then 4. 11's for a 3rd gear launch.

 

[getblown5.9]

No wonder it looks like that . . . 3-4 seconds of slipping is an eternity

Just curious but why the 3rd gear launches? Starting off in 2nd should save the clutch.

so you are telling me that i cant sled pull or race at all with it then. im not gonna dump the clutch from 3800rpms to launch when racing the few times of the year i race, and when i sled pull i dont think im gonna get anywhere by dumping the clutch from 3800 in 4th gear either.

when i say slipping 3-4 seconds thats the time it takes for me to slowly let the clutch out, not like im holding there to slip that long.

 

[Forrest Nearing]

two points...



1. sled pulling is HARD on clutches... you're not going to just install a clutch in a sled pulling application and never have to worry about it again. I think the big boys get maybe 5 events out of a clutch before a rebuild?



2. if it's holding, I wouldn't worry too much... the frictions and steel aren't going to look brand new... you've definately put some heat through it, and since it's out, I'd probably go ahead and at least get new steel for it, but my guess is you could probably go again and put the same amount of abuse on it that it's already seen and it'd still be holding up good.

 

[getblown5.9]

I'll be pulling less than 10 times a year, but I bought a south bend thinking it would handle this but apparently not. I was told it was built for sled pulling, not that it would need rebuilt twice a year.

I was under a wrong assumption... thats my problem now. Not to mention the clutch holds better than the "bulletproof" NV5600 its hooked to, which is on its second rebuild of this year... and I haven't even pulled with it yet!

 

[Bandit1]

seems to me that there is another problem at hand here. 2-trans and a clutch that looks like it has been hot, i would rethink blaming the manufactures of these parts and search deeper to find the gremlin behind these failures.

 

[South Bend Clutch]

Folks, in all actuality the clutch does not look that bad. Yes, there is some discoloration but it is wear that we are looking for. In fact, sled pulling is much easier on a clutch then 3rd and 4th gear launches. with sled pulling you are in the dirt whereas launching on the street is on pavement. Anyhow, with as many pavement launches as we are talking about, the clutch looks pretty good... discolored yes, but pretty good. The clutch was holding good and not the reason for removal.



getblown5. 9, I saw the pictures in the email you sent last night. I am sorry that I didn't get back with you first thing this morning as I am off today. Feel free to call me tomorrow and we can discuss what you would like to do. But, please rest assure that the clutch looks normal. It only takes 4 seconds to reach a 1000 degrease, because it discolors does not mean it has reached the end of its life.



Peter

 

[getblown5.9]

seems to me that there is another problem at hand here. 2-trans and a clutch that looks like it has been hot, i would rethink blaming the manufactures of these parts and search deeper to find the gremlin behind these failures.

i never blamed a manufacturer, but my driving must be one of a kind abuse considering people sled pull, and drag race, plus tow HEAVY trailer with this same equipment and never have these failures. (2nd trans failure is only the input shaft bearing, which could possibly be related to the first rebuild and not replacing the bearings then)

i've been to the track a few times (once with the DD), and done some launches on the street, and never towed over 6k lbs... and my normal daily driving is no more than 15 miles with traffic so im not out there doing holes shots every day.

if an NV5600 and SBC DD cant hold up to that... then a built auto wont hold up either because there are 10 times the amount of things to fail

 

[JasonCzerak]

i never blamed a manufacturer, but my driving must be one of a kind abuse considering people sled pull, and drag race, plus tow HEAVY trailer with this same equipment and never have these failures. (2nd trans failure is only the input shaft bearing, which could possibly be related to the first rebuild and not replacing the bearings then)



...

What tipped you the imput shaft was broke? just a vibration? or did hte trans just stop?

 

[getblown5.9]

Folks, in all actuality the clutch does not look that bad. Yes, there is some discoloration but it is wear that we are looking for. In fact, sled pulling is much easier on a clutch then 3rd and 4th gear launches. with sled pulling you are in the dirt whereas launching on the street is on pavement. Anyhow, with as many pavement launches as we are talking about, the clutch looks pretty good... discolored yes, but pretty good. The clutch was holding good and not the reason for removal.

getblown5. 9, I saw the pictures in the email you sent last night. I am sorry that I didn't get back with you first thing this morning as I am off today. Feel free to call me tomorrow and we can discuss what you would like to do. But, please rest assure that the clutch looks normal. It only takes 4 seconds to reach a 1000 degrease, because it discolors does not mean it has reached the end of its life.

Peter

Thanks Peter, if you say it looks normal than it makes me feel better. I am going to just go ahead and put it back in since there is no hard parts damage, just wear. I need to get the truck back together ASAP anyways, since I'm tying up a buddy's lift.

 

[getblown5.9]

What tipped you the imput shaft was broke? just a vibration? or did hte trans just stop?

wasn't broke... the bearing was going bad... alot of rattle/clunking (not DD rattle) when the clutch was engaged in neutral there was a steady noise coming from the input shaft, also when shifting it would sometimes make a loud/hard clunk.

there may also be other bearings bad within the transmission, haven't heard from the transmission shop yet.

 

[Forrest Nearing]

well, when I said big dogs, I meant big dogs



your frictions still look almost new and the steel isn't dug in or worn... you should have seen the FE my buddy pulled out of his truck... the entire friction faces were gauled up and the flywheel and pressure plate had trenches dug in them. your steel still has machining marks on it

 

[dpuckett]

I'm not sure how you start off, but I normally let all the slack get out of the drivetrain, THEN mash the go pedal. It makes for slow shifting, and if you are that into dragging, then go to an auto. If not, just go easier on things. I'd bet money the guys who haul 30K GCVW dont do any 3rd gear launches, or even 1st gear launches. It's all in the amount of shock you put to the drivetrain. I have had 25K a few times, and I accelerated at all the engine could put out, but I also shifted REAL easy, and got back into the pedal real easy.



These aint little Vette trannies, and they dont have a high-revving, no bottom end gasser in front of them. You almost have to shift them like an 18spd behind a 444 Cummins- slow and easy- transmission determines how fast I shift. Heck, bgilbert is putting 950lb-ft through a STOCK GETRAG.



Daniel

 

[pwerwagn]

if an NV5600 and SBC DD cant hold up to that... then a built auto wont hold up either because there are 10 times the amount of things to fail

A full billet auto is stronger than a 5600 any day, IMO.



--Jeff