The pulley that drives the transmission may have debris stuck on it and causing the drive belt to slip and smoke. You always want to check all pulleys to make sure long grass blades or weeds are not wrapped on them and binding them. You also want to keep them well-oiled as described in your owner's manual.
I use a flathead screwdriver... but they make a tool. I would guess you could rent the tool from a sears or a Lowes.. but hey, if you have a lawnmower, i bet you have a screwdriver.
Murray typically puts their tags on the very rear of the mowers in the center below the seat.
Right side of engine on rear
Either a nut on the axle or with a C clip against the outside hub of the wheel.
The diagram should be on a label on the deck or on the rear of the mower. If it is gone, then your local mower repair shop can probably print you one out for a small fee.
The first place I'd check is on the rear of the tractor, somewhere above the PTO riveted onto the case rear of the tractor.
how do I check oil in the rear end of a 3600 ford tractor
The retainig ring has "tabs" that protrude above the groove where the ring fits. You may be able to grasp one or both tabs with needle-nosed pliers and remove the ring.
For stability and traction
A "mechanical front wheel drive" tractor has front-wheel-assist which means that not only the rear drive wheels pull the tractor ahead, but the front wheels also pull the tractor.
If they are regular tires and the tractor is 2wd they are 11.2-24 and 4wd they are 9.5-24 If they are turf tires and the tractor is 2 or 4wd they are 41x14.00-20
Murray