Dual mass clutch

[Prairie Dog]

Are all dual mass clutch setups as short lived and problematic as the stock unit they put behind the G56?
Are there improvements to NVH by going to a dual mass clutch? Not concerned about price if it will last and perform well.

I want the smoothest, most quiet Kevlar clutch I can find and want to know if there is any benefit to going DM if I don't run big power.
I welcome your opinions.

Thanks in advance,
Scott

 

[BigPapa]

I think you're possibly confusing dual-mass and dual disc. I am not aware of an aftermarket dual-mass system.

Current offerings of dual disc street clutches are very smooth, very strong, and quiet. I would go with a dual disc now if I still had a manual and, I have to say it, South Bend has been very good to me, my friends, and customers. Give Peter a call. He won't steer you wrong.

 

[Prairie Dog]

I think you're possibly confusing dual-mass and dual disc. I am not aware of an aftermarket dual-mass system.

Current offerings of dual disc street clutches are very smooth, very strong, and quiet. I would go with a dual disc now if I still had a manual and, I have to say it, South Bend has been very good to me, my friends, and customers. Give Peter a call. He won't steer you wrong.

Your right, I am confusing them. Thanks for the information.

 

[Doubleclutch]

Do call Peter. He'll give you good information with options.

 

[RVTRKN]

What is your current HP, if stock, I would not go with SDD 3250 which is a street dual disk. If you have a G56 it will transfer the harsh pulsations at a higher rate and transfer the noise to the trans. I have a SDD 3250 clutch and its noisey as well as it makes the trans noisier. Peter just discussed this at May Madness and doesn't recommend one if your stock or under 500 HP due to the harshness to the trans from the powerfull Cummins NVH.

 

[Tuesdak]

What has you sold on Kevlar or other "exotic" clutch material or dual disc? With the luck you have had I guess smooth is the #1 goal?

If you aren't over the power level: I would suggest the 1947-OK-HD as it is smooth and quiet. The downsides are heaver rotating mass and heaver pedal as the pressure plate has to clamp harder. The rotating mass means a longer delay between gears, but, I can't see it being heavier than a dual disc clutch. (I am at stock power.)

I would replace both the engine rear main and front trans seal while you are there. I also did the hydraulics and added the flywheel kit with HD pilot to hopefully eliminate any lingering issues. While it's out I would consider freshening up the trans depending on miles.

 

[Regcabguy]

What is your current HP, if stock, I would not go with SDD 3250 which is a street dual disk. If you have a G56 it will transfer the harsh pulsations at a higher rate and transfer the noise to the trans. I have a SDD 3250 clutch and its noisey as well as it makes the trans noisier. Peter just discussed this at May Madness and doesn't recommend one if your stock or under 500 HP due to the harshness to the trans from the powerfull Cummins NVH.

Yep. He talked me out of one. My OKHD has been pretty good so far.
Awhile back I drove a recently purchased 2005 G-56 w/237K on it. The pedal pressure was greater than mine with the 3250# pp but smoother. The trans was as quiet as with our dmf stockers.
The owner was going to contact the seller and get the particulars. I'd like to know what clutch that was and especially what fluid he was using.

 

[Prairie Dog]

What has you sold on Kevlar or other "exotic" clutch material or dual disc? With the luck you have had I guess smooth is the #1 goal?

If you aren't over the power level: I would suggest the 1947-OK-HD as it is smooth and quiet. The downsides are heaver rotating mass and heaver pedal as the pressure plate has to clamp harder. The rotating mass means a longer delay between gears, but, I can't see it being heavier than a dual disc clutch. (I am at stock power.)

I would replace both the engine rear main and front trans seal while you are there. I also did the hydraulics and added the flywheel kit with HD pilot to hopefully eliminate any lingering issues. While it's out I would consider freshening up the trans depending on miles.

A mechanic buddy of mine has been installing clutches in everything from pickups to medium duty and OTR trucks for 25 years. He swears by the Kevlar units. They have smooth engagement and cause virtually no wear to the flywheel.
The only reason I would consider a DD clutch is for NVH purposes - that's why I was asking for opinions about them. My HP will never exceed 400.
Lots of good comments folks. My truck only has 94K on it so no trans work needed but I will have the seals in both trans and eng done while they're in there.

Scott

 

[Joseph Donnelly]

Talk to Peter. Kevlar is a good material, but special purpose. Organic is fine for low to moderate HP. I got very little flywheel wear with his feramic material, for that matter.

 

[Prairie Dog]

Well I currently have the ConOfe and wouldn't use another one if they gave it to me, installed it for free and took my family to Disneyland.
I can guarantee I have massive wear to this lousy clutch because I have to slip it hard every few days to keep it from getting so grabby it wants to spit gravel every time I take off in it. It's like having a switch - it's either on or off. I can only imagine what's it's doing to the rest of the drivetrain.
I've finally gotten so frustrated that lately I've gotten into the habit of slipping it hard before going into 3rd gear every few days. Holding the RPM's at 2500 RPM and slipping it through an intersection makes it behave for a day or two.
Yea, I hate this clutch and I'm not putting any "feramic" crap back in my truck. (OK, rant off)
If I can get Peter on the phone (tried twice now) I will consider an organic.

Thanks for the feedback.

Scott

 

[Tuesdak]

*Shrug* To me flywheels and brake rotors are wear items and 99% of the time I toss them rather than re-work them. So wear on a flywheel or brake rotor isn't a concern to me. I have had some rides with aggressive pads that take the rotors below min spec before the pads are on the squealers.

What is a concern is "hotspots" that can't be machined out and quickly return as high spots in brake rotors and flywheels. 3000 miles is about the return time for machined (cut) brake rotors. My 1st clutch had hotspots you could feel with a fingernail due to the missing pin and could grab hard enough to stall the engine at 1/2 pedal. This is when I replaced it the 1st time flywheel and all. You bet when the redid the clutch after 15K miles I was nervous about machining the low mile flywheel! With the cost to drop the trans it is cheap to replace the flywheel while you are there. I also went with the HD pilot - another reason to replace the flywheel.

With the grabbing and slipping you have had to do I suggest replacing the flywheel as it likely has hotspots. Maybe tear it down first to be sure.

I have missed the 3rd to 4th shift getting 6th instead a couple times. The 1947-OK-HD held where the stock clutch slipped. Although my old clutch was damaged this clutch is smoother and predictable. This alone is why I decided against the exotic clutch materials. The constant hills and serious grades around here are tough on clutches so the temptation was there...

 

[RVTRKN]

I can say my dual disk is allright and slips well when engaging, but if I didn't need it, I would change it to something quieter. It has performed as advertised, but when I can work out the glitch when in regen, I'll change it to something in a stock form clutch.

 

[seafish]

I have driven on the Con-OFE for 6 years now…while it does tend to be a little noisier in low speed or lugging situations, and also a little grabbier on enagement, I simply modified my clutch release technique to use a little more fuel in order to slip the clutch just a little on engagement and overall it performs perfectly well in my truck either loaded or unloaded. I WILL change the lube to Mobil Delvac 50 at the next lube and see if that will quiet it down some. I am also laying down 2#/sq ft lead sheeting over the transmission hump and floor and up the firewall in order to quiet down the truck even more and I am SURE that will help with G56 noise reduction as well, though it is part of another project.

 

[RVTRKN]

seafish, Peter from SBC recommended Mobil Delvac 50 when high perfomance clutches are used on a G56, due to the harsher NVH from the stronger clamping power of a high performance clutch. It is what I have currently in my G56, and has quieted it for the most part except for the marbles (lugging) sound when below 1500 RPM. Although, keep in mind the heavier oil has a harder time of shedding the heat generated, so at a minimum install coolers on your PTO openings. I have my cooling system installed so it doesn't effect my G56.

 

[Regcabguy]

I've read several posts of guys having luck with Amsoil 75-90 gear/trans fluid.
One guy experiences -10F and says no problem.

http://www.amsoil.com/shop/by-produ...-transmission-and-transaxle-gear-lube-75w-90/

 

[AllianceDiesel]

I use the southbend okhd kit when replacing dual mass flywheels/stock clutches. It is a very good clutch for stock to mild power. On the pickups with mid to high hp they get a street dual as long as they will never sled pull. As far as oil I have used trans 50 on 2 pickups and a trans 50/royal purple syncromesh mix on another. All seem to shift just fine in the cold and gets rid of 90% of the noise. If it gets real cold, set parking brake, shift transfer case to neutral, and put the trans in 5th. Helps to warm up the fluid.

 

[inlinesix3million]

I have driven on the Con-OFE for 6 years now…while it does tend to be a little noisier in low speed or lugging situations, and also a little grabbier on enagement, I simply modified my clutch release technique to use a little more fuel in order to slip the clutch just a little on engagement and overall it performs perfectly well in my truck either loaded or unloaded. I WILL change the lube to Mobil Delvac 50 at the next lube and see if that will quiet it down some. I am also laying down 2#/sq ft lead sheeting over the transmission hump and floor and up the firewall in order to quiet down the truck even more and I am SURE that will help with G56 noise reduction as well, though it is part of another project.

Check out the peel and stick Ensolite closed cell foam at raamaudio.com . Do a couple layers over your other stuff. I have had great results quieting my interior with this. I lifted the factory
firewall pad as high as possible and got in as far as I could with this stuff. I have the electric 4 WD selector on the dash. When I removed the carpet to sound deaden I noticed a thick
plastic cover over the opening for a manual gearshift for the transfer case. I replaced this cover with some sheet metal and then put the Dynamat and Ensolite over everything. It is noticeably
quieter. You can trace the bolt holes onto the sheet metal and reuse the bolts. Just put some RTV on the bottom of the patch or use the Ensolite to make a seal.
Also- When installers use Dynamat, or any equivalent, it's purpose is to add "mass" to a flat,open area of sheet metal. This eliminates the buzz/rattle you hear on some vehicles when they
have hi-power sub woofers cranked up. This sound typically comes from doorskins,trunk lids, and roofs. The floorpan is a heavier gauge and does not need the mass. I used it to add a level of insulation and seal. The closed-cell foam is what provides the sound proofing.

 

[Sean Flanagan]

I have the ConOfe as well

Well I currently have the ConOfe and wouldn't use another one if they gave it to me, installed it for free and took my family to Disneyland.
I can guarantee I have massive wear to this lousy clutch because I have to slip it hard every few days to keep it from getting so grabby it wants to spit gravel every time I take off in it. It's like having a switch - it's either on or off. I can only imagine what's it's doing to the rest of the drivetrain.
I've finally gotten so frustrated that lately I've gotten into the habit of slipping it hard before going into 3rd gear every few days. Holding the RPM's at 2500 RPM and slipping it through an intersection makes it behave for a day or two.
Yea, I hate this clutch and I'm not putting any "feramic" crap back in my truck. (OK, rant off)
If I can get Peter on the phone (tried twice now) I will consider an organic.

I have the ConOFE as well don't like it either. OK, it doesn't slip, but it is too grabby and backing up is a pain. It is one of the worst things I did to my truck. Like driving a tractor now. Anybody who drives my truck tells me there is something seriously wrong with the clutch. The sad part is, I have been living with it for many years and over 100k miles. Someday... I will change it. It was in expensive mistake.

 

[Doubleclutch]

I also had the ConOFE in my '96. At the time, it was the only clutch that would hold the power, and the trade-off at the time was acceptable. I also observed the same frustrations, and it kept my wife from driving the truck. <G>

 

[Sean Flanagan]

I also had the ConOFE in my '96. At the time, it was the only clutch that would hold the power, and the trade-off at the time was acceptable. I also observed the same frustrations, and it kept my wife from driving the truck. <G>

I actually had the CONofe on my old '98. It worked well, which is why I got the "ofe" for my '07. Something different about these newer trucks though. Doesn't work nearly as well.