On my slip yoke I needed some heat to get it to loosen up. I used a map gas torch, a big ass adjustable wrench, and a pipe wrench to keep the drive shaft from spinning. Since then I have bought a big ass metric wrench to fit the locking nut of the collet. I'm pretty sure the size is either 27m or 32m. If you need to know for sure, give me a shout and I'll go into the garage and look.