According to all the listings I can find, my truck takes a 10" clutch. Its a 96, 2WD, M5OD with a GVWR of 6250 lbs. Picked up the 10" clutch from NAPA, measured it, its 11" across. The clutch out of the truck is also 11" across. The new NAPA clutch has more surface area to the one I just pulled out (which is an aftermarket one). What is the difference between the 10" and 11" clutches (is the 11" actually 12" across?)? Does it matter which size clutch goes in?

 

Are you measuring across the CLUTCH (the fibrous part), or the pressure plate in the diaphragm? The clutch should measure at its nominal size.

Most of those flywheels are drilled & tapped for both sizes of clutch, but to go from 10 to 11, you'd need to have it resurfaced. To go from 11 to 10, that's not necessary.

 

If you are going to go to the trouble of pulling the tranny and bellhousing out to change the clutch, you might as well get the flywheel resurfaced anyway, and replace the pilot bearing/bushing. It's like doing brakes without turning the rotors or drums.

 

I measured across the clutch itself, not the pressure plate. The new pressure plate also has a corresponding larger contact area than the one I took out.

 

I'm not sure ho big they are supposed to measure, but I put an 11" clutch in my truck that has the same engine and tranny as yours but it originally came with a 10" clutch. No problems at all.