Engine/Transmission (1998.5 - 2002) Clutch "flex plate" torque rating?

[Gary - K7GLD]

There's a couple of threads here related to failures of automatic transmission flexplates - the plate between the friction materila and hub on a standard transmission setup is pretty much the equivelant. The material used seems to be some sort of spring steel looking stuff, and not REAL thick or hefty at that - nor do the securing rivets appear to be terribly rugged...



SO, how often do these fail - sure don't see many reported here - and does anyone know what the actual torque rating is for a stock-based clutch assembly? For the record, some (maybe MANY!) aftermarket outfits seem to use the stock hub, flexplate and base hardware as the starting point for their "high HP" clutches - but like a chain, the best clutch going is no better than its weakest point...

 

[Pmaloney]

I would have to say that the springs in a clutch disc help absorb alot of the shock load where-as a flexplate in a automatic is a direct link to the transmission, so with a firm full throttle/max power shift, there is no cushion between the flexplate and torque converter, but yes, I have seen people tear up a clutch disc to.

 

[NIsaacs]

Gary,



Good question! I would like some feedback on this subject also.



When I did the Cummins install in my Ford back in 1990, there was not many options for Clutch or Transmissions. I went with the so called bullet proof, Clark 280 VO. I have lost 5th gear 3 times and 3rd gear once. I used the Chevy application case/12 inch x 1 1/8" 10 spline shaft clutch and have lost the clutch about 6 times. I have tried all types of heavy duty clutch plates but lose the center hub every time. The torque seems to compress the springs to the point of hitting the stop pins. When the hub fails and breaks, the springs are destroyed and the stop pins will be about half wore in two. I have never had any issues with the clutch slipping, no matter what type linning was being used. It seems like all the heavy duty type clutches consentrate more on clamping force or linning material than torque capacity of the springs/hub.



I have never lost a clutch in my "91" with 13" clutch, however I don't haul heavy with it like I have with the Ford.





"NICK"

 

[Gary - K7GLD]

What really amazes me, after looking at the construction of the hub/flex area of a "upgraded" clutch, is that in many cases the transmission input shaft will fracture before the clutch flexplate. You sure wouldn't think so after looking at one closely. If there's enough interest, and some here haven't actually seen how these clutches are made, I can post a closeup pic of what I'm talking about...

 

[jrobinson2]

Gary,

Actually there is usually a thread ever few months about a blown clutch disc with the 5 speed clutches, I helped change one last month. The thin part that looks like it would be marginal in a honda was fine, the part that sandwiches the damper springs separated, I have pictures but my computer and my camera software are not on speaking terms right now :-{} I think Southbend no longer sells the more aggressive clutches in the 5 speed size, they re-drill the flywheel to accept a 6 speed clutch, it has a much stronger center.



Jared

 

[Gary - K7GLD]

"The thin part that looks like it would be marginal in a honda was fine"



*THAT'S* the part that amazes me!