Paul, we are going to need the technical model number and serial number of the tractor in order to find an online parts illustration to see what might be possible.
In your statement you say "battery removed and belt removed.".
Which belt are you referring to? Surely not the belt that drives the transmission?

It sounds like the flywheel in question is the input pulley of the transmission. This is a single speed MTD transaxle. Clicking is never good when it comes from inside. 13AP60RP544 or /744 would be the MTD model. Parts are serviceable internally if you wish to go that route. An assembly is ~ $400.

I have seen/heard many a component labeled with a misnomer, but that one flew right past me.
Good save Tom!

Model # 13AP60RP744.

That is correct its the flywheel that sits on top the transmission.

I took the belt off the pulley to see if I could Identify narrow now the problem. When I put the shifter in the forward position the mower rolls like it is in neutral. No resistance at all.

I have the transmission off and took it apart and I can see any damage. I am assuming the damage is to the differential asm. I believe that part can be replace for around $270.

Does this sound like a correct diagnoses?

Thanks,
Paul

Here is a link that might be useful: PartsTree

I wouldn't say you are incorrect- tho I wouldn't want to make that assumption w/o tear down. Think of the fact that the input gear and forward bevel gear may be the culprit as well. Bearings etc need to be factored in, the shift fork can fatigue on this style of transmission too. You may want to hit the web looking for a deal on the whole assy. Is there an MTD # on the housing? Does the differential make crunching noises on tight turns?

Before you go and order a differential assembly, how about posting some good close up photos of items # 15 and # 9 (in the IPL).
Those 3 are the only gears associated with forward and reverse.
The differential gears really only get active during turns. Though they will activate and allow 1 wheel to spin fruitlessly if traction conditions are lousy.
If you jack up the back of the tractor so that both drive wheels are off the ground, and spin one wheel, the opposite wheel should rotate in the opposite direction from the one you are spinning. If it does that, and you don't hear any crunchy sound while doing it.........the differential is OK.

I have a LX-500 with single speed transmission and reverse. Unit quit moving forward and made a lot of noise when the accelerator was pushed; also, the transmission was making a loud whining sound before it quit. I have taken the transmission out of the mower, removed and cleaned all the internal parts. I have found that the brass bushings (item #'s 14 & 21) are worn out, and that the steal bushings (4-item # 11) are loose, I am going to replace the seals (2 item # 12).
I will let y'all know how this repair turns out.
IH