Can anyone tell me what kind of clutches are in the big rigs? I drive freightliners, volvos, macks, and the occasional international around in circles at work and like their clutches. I can launch in second or third with 40k on back or even higher gears unloaded and still have the ability to inch a trailer backwards by feathering the clutch. I really like the clutches in those things whatever they are.

With that said I'm going to need a clutch soon. Seems almost everybody on the board short of one guy are big fans of the south bend clutch. OFE is oragnic on one side and iron on the other and FE is two iron plates. I've read that the FE tends to be grabby. I've also read some good things about the LUK cermametallic clutch- in that it allows you to slip the clutch then holds when released. This sounds more along the lines of what I'd like to have. Only negative thing I've read about the cermametallic is that Peter at SBC beleives that this material will not last as long as the materials used in the SBC's.

I'm not trying to start a flame war- just looking for opinions. PM's welcome.

 

Look at this... http://www.southbendclutch.com/dd.html

Reportedy they drive pretty dern smooth if you don't go with the monster one.

Just thought I would throw this in there if you like the feel of the big truck clutches.

Peter

 

What he said...mines a little jumpy but with a few RPM it smooths right out. I'll never be without a DD againLD

Chirs

 

Ok, I hear the DD SBC is noisy and slow shifting. Are you saying the big trucks use a dd clutch? I'm just looking for discussion and to be frank, discussions I've read here in the past have me leaning towards a Luk cermametallic. DD are better for a third gear launch? I've only tried it once and my poor clutch smelt like it was burning up

 

Yes, the DD is a little noisy. I kinda chugs along at idle just like the Cummins rattle...bring the idle up to 1000RPM and it goes away. Slower shifting, YES, but consider that there is A BUNCH of clutch swinging on that shaft. It's not too slow, but I didn't buy my truck to drag race, but I can still bang gears fairly quick, regardless!

The DD are made to slip and go on living like nothing happened (to a certain point, though). Once they hook, it's off to the races

Chris

 

i don't have any noise or vibration out of my dual disc

 

The LUK Cerametallic, while an outstanding all around clutch, is NOT a good third gear launcher or sled puller. The nature of the cerametalic material is that is has a large difference between the coefficient of static friction vs. the coefficient of dynamic friction. Its coeff. of static friction is very high, but the coeff of dynamic is fairly low and the pressure plate load is also fairly low. In fact the pedal effort is much less than stock. Once locked up, this clutch will NOT slip with up to 1,000 Ft *lbs. BUT, it is not a clutch which you will do a high RPM, boost up, long slipping time launch, like a sled pull, or a third gear launch in 4wd, because with the modest plate load and the lower coefficient of dynamic friction it wont lock up with all that torque and RPM, and as it gets hot, the dynamic coeff drops off even more, so it fades and will continue to slip until you back out of the pedal. For normal romping around its a great clutch, and like I said before, once its locked up, it holds visciously!! One guy on here is making 1,000 Ft*lbs+ with twins, and runs this clutch, and has no issues, but he doesnt sled pull or do long slip time launches in 3rd. Its just not a good slipper, and wasnt designed to be.

If you like long slip time 3rd gear launches or want to sled pull, which also necessitates a long slip time, you will need to look at dual disks. There are several manufacturers of them out there.




KP

 

i think i have an aftermarket clutch my truck is an early 04 6 speed the pedal is pretty stiff and if i put in second and just let off the clutch and just let it idle it makes this weird rattle noise what is that noise and how can i tell if its an aftermarket clutch or not

 

im running a sbc dd clutch, its harder to push in and its noisy and its slower to shift but it holds great! id do it again in a heartbeat. i recommend them!

 

is there any way to tell if its not factory and how could i burn it up...... i dont want to just wanna know what will so i dont do it

 

i have 2 friends running the luk pro gold but they use a ferimac disc(like the SB fe) in it instead of the cerametalic and have not been able to slip it. both of them have a zero plate and 370's

 

600 megawatts:

How would it be for towing ? I don't know for sure how you consider 'normal romping around" with regard to ability to tow. I'm sure it would be less of a load than the sled, but having never pulled, I don't know for sure. I'm mainly interested in the ability to get up and go with 5 or 6 tons behind me, no high rpm launches here. Just good steady acceleration (not grand pa type either).

 

TRCM, that is exactly the type of towing I do. I pull around 10 to 11k. There is absolutely no problem at all doing that. I have a 6 sp, and if I am stopped on a grade I start in 1st, most of the time on level I start in 2nd just like normal. It never slips, not with my mods at least. I never ever need anything other than 6th up long highway grades, and could go at ludicrous speeds up them if I wanted to. The only issue, is that its indeed a metallic clutch, which means it can chatter. When I first put it in, it did not chatter at all, it was totally smooth, but after about 2k miles, its seated nicely now, and it can chatter when backing up the trailer slowly. I just use 4 low for that, so I don’t have to feather the clutch. Lots of other guys do this same thing to deal with the chatter of highly feramic disks as well. Unfortunately, its a necessary evil once the metallic content goes up....


As for 'romping' around, I am about as hard on it as you can be, short of third gear launches. I drag race it at the track a few times a year, with hard 4wd launces, ( but starting off in second), and I am constantly hammering the gears and getting rubber around town. Put it this way, I have yet to get anywhere near 1 year out of rear tires....


And lastly, I would like to comment about the third gear launches and dual disks.... First of all, 3rd gear launces have become popular partly, as a RESULT of dual disk clutches. What I mean, is that the dual disk clutches shift so much slower as a result of their increased rotational inertia, that they almost necessitated the third gear launch, since shifting from 2nd to 3rd was so painfully slow... Also, guys who have 4.10 rears do much better launching in 3rd gear, because 2nd is just too low with 4.10's, you are shifting almost immediately after launch... In my case, with 3.54's a third gear launch has the cerrametallic slipping too long, and it gets hot and fades. But the other side of that is that I launch very hard in 2nd and can bang third like its nothing. When 'romping' around, I never even take my foot of the accelerator, I keep it floorboarded, and just kick the clutch to the floor and bang the next gear in one fluid motion and get rubber on every gear change until 5th. The cerrametallic disk is lighter than stock, making these really fast gear changes easy, so the need for a 3rd gear launch is drastically reduced in the first place, especially if you have 3.54's


OK, the company is here now, gotta go…. Happy Thanksgiving to all my friends on the forum.!!!




KP

 

The LUK Cerametallic was tested by Joe Donnelly, a CTD clutch pioneer, over on the TDR. On a 3rd gen it started slipping at the 470 hp level, even on the dyno. Southbend's Con FE is a much better single disk clutch, but also much more expensive.

 

600 megawatts:

which part number did you use ?? or do you remember ?

I think the 05-118 is the cerametallic one, and 05-902 is the pro gold.