Engine/Transmission (1998.5 - 2002) Con OFE Failure

[DPrew]

My Con OFE died after only about 13 months. The springs broke and the clutch went to hell. Southbend has made changes to the new Con OFE because I suspect a lot of people running close to the 450 HP limit were having failures as well.



The new clutch has more springs that are smaller. This new style clutch is noisy and vibrates when you put the truck in neutral. I thought something was wrong with the clutch the first time I drove the truck. The good news is the clutch stops spinning much quicker now. You no longer have to wait three seconds at stop lights to put the truck in gear. The only drawback I've encountered is the clutch has extremely violent engagement when under a heavy load.



I was sitting at a stoplight with 18K in tow point up a slight hill and couldn't help but bounce the front end like a low rider on take off. The old style clutch had to be let out really slowly or it would jerk violently as well. This new clutch seems hell bent on kicking my but. No matter how smoothly you let out the clutch the truck jerks so violently at times you have to push in the clutch and try a second or third time.

 

[NoSeeUm]

Damn if can remember where I read it, but I just read it the other day.



Somewhere.....



A shop guy wrote that he had such problems with some SB clutches unless he had the flywheel milled flat. He indicated that even new flywheels could be out and now has them all milled before he does an installation.



Jim

 

[blacksheepdiesel]

DPrew,

Call Peter and tell him what is happening. I suspect he may tell you to do make an "adjustment".

I have the new style Con OFE and have grossed 27,000 lbs with it and it has never done what you are describing. Even with 3. 54 gears.

Godspeed,
Trent

Godspeed,
Trent

 

[DPrew]

I asked my mechanic about milling the flywheel with the replacement clutch and he said the HO flywheels are so thick that he's never had a problem with them getting out of tolerance. He usually just used sand paper to put a better finish on the flywheel to help it get seated.

I had a different mechanic do the first install and he did have a machine shop check the tolerances and hone the surface.

 

[blacksheepdiesel]

Peter told me the reason the single disk clutches started failing was because the newer boxes add power down low in the rpm band - exactly where it is hardest on the clutch disk hub. That is what failed on mine. It never ever slipped even though I was pulling a 20,000 gvw 5th wheel into 40 mph head wind when the center hub broke.

Godspeed,
Trent

 

[BigPapa]

... he said the HO flywheels are so thick that he's never had a problem with them getting out of tolerance. He usually just used sand paper to put a better finish on the flywheel to help it get seated.

I doubt this would be the SBC approved procedure for a new clutch installation.



Scott

 

[DPrew]

My clutch never slipped but it became harder and harder to shift. Finally, the truck had to be turned off and put in gear so I could get it to the shop. My SBC hydraulic clutch assembly had been making popping sounds for a while so at first I thought the hydraulics had gone bad. I replaced the assembly and the truck lasted a few more days before the clutch failed to disengage.