I have a John Deere 870 tractor. The clutch will not fully disengage when the tractor is hot, but shifts OK when first started. The clutch linkage is properly adjusted as per manual with 1/2" free play measured at the pedal. Why would the clutches be dragging? Is there any way to adjust the dual clutch other than the linkage without splitting the tractor? I know that there are adjustment bolts on the clutch pack, but don't know if they can be accessed from the little port on the side of the housing or if they will do any good. Both the traction and PTO clutches drag.

Also, if I do split the tractor does anyone have feedback on aftermarket rebuilt clutch packs? I'm assuming at this point that I'll want to replace the entire unit instead of just the clutch disks, but obviously don't know yet.

The dealer wants $4,800 to do the job, but he's charging something like $2,600 in parts.

Any advice would be appreciated as I'm not sure to trade up or fix.