As a final follow-up, I bought the Cub Cadet service manual that covers the LT-1050 model that I have. My first step was to do a thorough cleaning of the area under the engine. There is a yellow painted plate that is above the pulleys on the engine crankshaft. There is a black painted plate that is above that which has the steel tabs that tend to prevent easy replacement of the transmission drive belt. After the cleaning was complete, I first replaced a worn out steering shaft bearing. The steering bearing goes on top of the yellow plate under the engine, not under it as one YouTube video said. Mine was still intact although badly worn. The new bearing went into place after the steering column and steering wheel was pulled up enough to provide clearance for inserting the bearing into position. I used the blue CV join grease on it to help get the part to stick to my finger while positioning the part. Then while I held the steering gear and washer in place against the Steering Gear, P/N 717-1550E, I had my granddaughter to slowly press down on the steering wheel until it was seated as far as it would go. Then the locking nut was replaced on the bottom of the steering shaft.
Next after reading the service manual, I used the technique mentioned - removing spark plug wires then removing one spark plug and pushed some 1/4 inch diameter cotton rope down into the combustion chamber to prevent the engine from being able to fully turn over. This provided enough resistance to break loose the retaining bolt on the bottom of the PTO pulley. The PTO pulley and electric clutch literally fell into my hands as the bolt came off. It turned out to be easy to remove the remaining drive pulley from the crankshaft using a pulley puller tool I had on hand. I cleaned the fan that goes on the transmission pulley and with the fan removed I managed to feed the new belt first to the engine pulley and push back into position, then slipped it over the transmission pulley and around the tension pulleys. A 5/16 inch nut driver serves to remove and re-install the screws that hold the fan to the transmission pulley.
My local dealer had told me I would have to unbolt the engine to get enough clearance to get the belt around the engine pulley, but I did not have to do that. Everything went back together as it should have. A test after the drive belt installation confirmed proper operation. No adjustment of the transmission linkages was needed.
I also had to replace the Clevis Pins, P/N 711-0332, that hold the Deck Bracket, P/N 783-0720A, used on the 46 inch and 50 inch decks. These clevis pins had worn so badly that the holes where the Click Pins, P/N 714-04023, were badly wallowed out and the click pins were almost worn apart. I used some 1/2 inch bolts and locknuts to replace these. When re-installing the mowing deck I had to place two sets of 2 X 4 pieces of lumber under the front wheels of the mowing deck to get the holes to line up with the deck bracket and the mating holes in the frame.
The job took me most of the day. I am a senior citizen and have arthritis etc. and just do not work fast. A younger person could easily do better.