Sal's got the answer, Trap. It has to be set up right to get the pins in. I used my roll-around floor jack the first time and raised it into position with that. Even then I had to do a little grinding to get one of the pins to go in...the other one slipped in easily once the jack held it in position.
The next time around I decided to check out the setup and found that the connecting rods that go forward from the 3 pt. hitch arms needed to be shortened as specified in the Mower Adjustments section of the mower manual (mine's an RCK60-24B on a
B7610). Basically you shorten them until the holes line up on the front hanger brackets and the rear stoppers are either just touching the frame (left side) or clearing the frame by about 1/4" (right side). You should refer to your manual so that you know exactly what parts these are and where the clearance is measured.
After mowing I noticed my adjustment had been lost and the left side of the mower deck was very close to rubbing the left rear tire when raised. After fiddling with connecting rod adjustment again, it dawned on me that the adjustable right side lifting rod (turnbuckle) on the three point hitch wasn't locked and that the right side 3pt hitch arm was sagging. As a result, the right side of the mower was sagging when raised levering the left side up and nearly into contact with the tire. So before making your connecting rod adjustments, level up your 3pt. hitch arms and lock the hitch turnbuckle.
I'm surprised that the mower manual doesn't mention that right-side connecting rod adjustments are dependent on the hitch turnbuckle setting. If, after setting connecting rod length correctly, you were to raise the right side hitch arm by shortening the turnbuckle, you could easily overstress or possibly break the mower lift linkage.
Even when set up correctly (I think), the rear of the mower deck only clears the left tire by a few millimeters. When parked on a slope it sometimes appears to touch, though I've not yet seen any rub marks. As part of setup, the I feel the dealer should've made sure that the pins could be easily inserted and removed. If they'd done this, they would've known that the mower connecting rod setup was wrong. They should have also warned me about changing the length of the 3pt. hitch turnbuckle. Apparently this is something that's not stressed in their training.
FWIW
Bob
