I believe the nut size is 15/16. I used to own Tru-Cuts when I lived in Los Angeles, but now I only have an old Cooper Klipper front throw which I keep for nostalgia reasons. The Cooper uses 15/16 jam and regular nuts.

I ended up buying a 15/16 x 1" wrench and grinding the flats down to about 1/4" or so.

To adjust, start with the reel drive first and break the large nut free of the jam nut using either a tappet wrench or modified regular wrench. Tighten the main nut until the clutch begins to engage about half way down on the control rod. The tighten the jam nut against the main nut. You don't need to fully tighten the jam nut because you'll nee to go back and check the adjustment and possible re-do several time. Correct adjustment is tight enough to fully engage the reel without slippage, and able to go past the detent to stay engaged, yet loose enough that there is no drag or creep when disengaged.

Then go the the rear drive clutch (in the center) and do the same thing. Most professionals would set the drive clutch to engage with thumb pressure but not go far enough to go past the detent and stay fully engaged. Again you want it loose enough when not engaged to prevent creeping.

You may have to check and adjust several times going from reel to drive and back again. This is because the two clutches are on a common shaft and tend to affect one another. However, the reel clutch has less effect on the drive clutch, so you want to start with drive clutch. Once you think you have everything right, tighten down both jam nuts against their respective heavy nuts and check one more time as things may have changed slightly.

Two places sell tappet style wrenches in 15/16 x 1". Snap-On is the best but very expensive. The Thin Wrench is much cheaper and should do the job:

http://buy1.snapon.com/catalog/item.asp?item_ID=633544&group_ID=675024

http://www.thinwrench.info/51-15-16-x-1-double-open-end-wrench.html

Tru Cut has 1 inch nuts. One wrench needs to be thin. I bought the cheapest 1 inch wrench I could find and ground it down to fit.

Thx for replies. I think I understand the reel drive adjustment using the jam/main nut pair outboard of the right side (looking forward) mounting block. Still a bit confused about the drive clutch adjustment - is this done with the nuts on the left side of the shaft? These are oriented different than the pair on the right, there is a nut and capture washer on each side of the shaft drive sprocket.

how to you replace the rear wheels?

How do you replace the rear drive wheels?

My rear wheels are locked on my Tru-Cut, and the slightest pressure on the wheel drive button will cause the mower to go forward as if it was fully depressed. Upon starting with the button fully disengaged the mower will creep forward. This happened after the mower was in constant use, and after a 2nd refueling. Clutch needs adjusting due to overheating?