I've had a MMM on my 3320 since I bought it. We first planned to only use the 3320 for mowing lawn, but found that we needed something smaller for "trim work" near the house and around and between trees. We added the smallest hydrostatic mower JD makes. My wife does the "trim work" on the small JD and I do the bulk of the mowing with the 3320 MMM.
The 3320 with MMM is amazingly nimble. The only limitation is really due to its width, turning radius, and height (can't go under low trees). I do try to avoid real tight turns if the ground is soft (damp) to avoid damage with the R4 tires.
I take the mower deck off each winter. Its a bit of a process, but not really that hard. I created a step-by-step guide to help remind me of the steps:
REMOVING John Deere 3320 Mower Deck:
<>Fully raise mower deck
<>Turn off engine & secure tractor
<>Disconnect front spring assembly to allow front mower deck wheels to turn freely
<>Remove rear wheel pins and turn mower deck wheels sideways
<>Start tractor and raise deck fully
<>Turn steering wheel fully left
<>Turn knob to high grass cut setting
<>Lower mower to the ground
<>Turn off engine & secure tractor
<>Unlock & rotate front pivot assembly; unlock u-pins and remove front bracket; use a lever & fulcrum to lift front of mower deck a bit in order to remove front pin
<>Disconnect j-pins at front of mower and remove front mower brackets
<>Put on latex glove(s) and disconnect drive shaft; lay shaft sideways on mower
<>Remove locking rings and pins to remove adjustable yokes front lift arms; don’t rotate yokes
<>Carefully roll mower out from under right side of tractor
<>Clean mower deck - especially under the belt covers - before storing to avoid mouse nests
ATTACHING John Deere 3320 Mower Deck:
<>Before attaching, lube the mower deck (spindles and under pivot-point) and the drive shaft. Make sure to grease the inside of the PTO connector.
<>Leave front tractor wheels straight.
<>Remove the silver yoke pins from the back of the mower deck being careful not to rotate yokes.
<>Pull the mower deck underneath the tractor from right to left. Make sure drive shaft is at minimum length and laid straight (pointing backward).
<>Line up and attach both front green hangers using the spring-loaded pins. Make sure the pins go all the way to the back of the holes. It helps to lift the front of the deck a bit with a lever.
<>Start tractor and push the mower raise/lower lever forward - to lower deck lift arms.
<>Attach both rear silver yokes using the pins and split rings - rings on outside. You may need to lower the cut height to lower deck arms enough, and lift the rear of the deck to help align holes.
<>Attach the drive shaft.
<>Attach two ends of front lift yoke to the mower deck using the spring-loaded U-pins. Make sure the pins go all the way to the back of the holes.
<>Place the front lift yoke pins onto the hooks and rotate as far as possible.
<>Use a lever & fulcrum to lift the front of the mower deck.
<>With the front of the mower deck lifted, continue to rotate the front left yoke handle backward until locking pin is in place.
<>Attach the front mower deck caster wheel springs.
<>Remove the pins from the rear mower deck wheels.
<>Rotate the wheels 90 degrees (wheels on the outside) and raise the wheel height until about ½" is above the top of the deck. Replace the pins.
<>Raise deck and adjust mower deck height using knob on left side of engine. Repeat until desired height is obtained.
The hardest part is usually getting the PTO to connect. Sometimes it connects first thing - sometimes its a hassle - mostly because of having to reach into the center - the mower deck keeps me from being able to get closer.
Once connected in the spring I'll run some non-connected stripes across the lawn in one direction with the small mower (that deck is kept on all the time) and then mow a stripe with the 3320, compare the height, adjust, and repeat until I get the height right. Its pretty easy to do
