BuffaloGuy
07-26-2003, 16:36
I thought I'd share my personal experience and thoughts about this dilemma.
My rig, a '93, came with a dual mass (they all did then). It did lots of hard pulling of loads over 20,000 lbs. At about 100,000m I started to get a tick when the truck was idling. Most mechanics couldn't even hear it but I could. I searched everywhere for it, took it to sveral mechanics and even the dealer.
One mechanic was sure it was something wrong in the trans. and convinced me to let him drop it and rebuild it. Wrong! After he put it all back together with new parts and lots of bucks later it did the same thing. I was a little hot.
Out it came again and that's when he noticed the ever so little slop on the flywheel. The clutch disk looked perfect. The dealer only had one option, a single mass. So, lots more bucks later I then had a single mass flywheel, at about 100,000m. It lasted about 5000m and the clutch blew apart while pulling a load. They covered it because it looked like the mechanic damaged the clutch when assembling it.
Now at 200,000 with even more pulling of 20,000 lb. loads my clutch wouldn't disengage. I replaced both slave and master clutch cylinders since they were factory. No dice. The problem was inside.
This time the center of the clutch (the part with all the springs) was coming apart. The clutch disks looked great and of course, the flywheel was perfect too.
I read here that when switching to a single mass you are supposed to put in a vibration dampner, in the tranny on a 4WD or on the drive shaft on a 2WD. I asked the dealer about this.
They said that at first they were putting them in but then quit since they felt they were unneeded. They ain't cheap. $400 if I remember right. My didn't have one at the origianl change over and it made it about 100K so I skipped it again.
My feeling is BOTH options, single mass or dual mass, stink. However, if I had to choose I'd stick with the single mass. I don't like the idea of that big dual mass flywheel being bolted to the crank and vibrating back and forth and creating a knock. That's gotta be bad on cranks and perhaps blocks too. Maybe that is the root cause of some crank and/or block casting failures.
The single mass hasn't lasted any better for me but at least it was just the light clutch disk itself that was coming apart and getting out of balance.
Why do they need all the springs and such anyway? If it wasn't for that these clutches would last for 200K easy. Hope this helps someone.
Ken
My rig, a '93, came with a dual mass (they all did then). It did lots of hard pulling of loads over 20,000 lbs. At about 100,000m I started to get a tick when the truck was idling. Most mechanics couldn't even hear it but I could. I searched everywhere for it, took it to sveral mechanics and even the dealer.
One mechanic was sure it was something wrong in the trans. and convinced me to let him drop it and rebuild it. Wrong! After he put it all back together with new parts and lots of bucks later it did the same thing. I was a little hot.
Out it came again and that's when he noticed the ever so little slop on the flywheel. The clutch disk looked perfect. The dealer only had one option, a single mass. So, lots more bucks later I then had a single mass flywheel, at about 100,000m. It lasted about 5000m and the clutch blew apart while pulling a load. They covered it because it looked like the mechanic damaged the clutch when assembling it.
Now at 200,000 with even more pulling of 20,000 lb. loads my clutch wouldn't disengage. I replaced both slave and master clutch cylinders since they were factory. No dice. The problem was inside.
This time the center of the clutch (the part with all the springs) was coming apart. The clutch disks looked great and of course, the flywheel was perfect too.
I read here that when switching to a single mass you are supposed to put in a vibration dampner, in the tranny on a 4WD or on the drive shaft on a 2WD. I asked the dealer about this.
They said that at first they were putting them in but then quit since they felt they were unneeded. They ain't cheap. $400 if I remember right. My didn't have one at the origianl change over and it made it about 100K so I skipped it again.
My feeling is BOTH options, single mass or dual mass, stink. However, if I had to choose I'd stick with the single mass. I don't like the idea of that big dual mass flywheel being bolted to the crank and vibrating back and forth and creating a knock. That's gotta be bad on cranks and perhaps blocks too. Maybe that is the root cause of some crank and/or block casting failures.
The single mass hasn't lasted any better for me but at least it was just the light clutch disk itself that was coming apart and getting out of balance.
Why do they need all the springs and such anyway? If it wasn't for that these clutches would last for 200K easy. Hope this helps someone.
Ken