Well, from the description of the problem--something inside the transmission is obviously unhooked. If you can't see anything untoward on the outside, then a mechanic will have to take it apart to better see the problem.

Rustyj14...... Thanks for your insight. I am surmising that the arm that is welded/attached to the shift fork rod has come apart. Weld broken, or if a press fit, has enough hours to work loose. Anyone else have an opinion? I was an auto mechanic by trade, and haven't been into a rider before. Is this a job that one could undertake without a bunch of specialized tools? Any ideas as to cost and time to do the job, if the above is a possibility? Thanks, David.

Transaxle isn't technically difficult to work on, but can be a pain in the butt. You have to pull the transaxle out of the mower frame, which is a fair amount of work, then you split the transaxle cases after removing the screws. No special tools are needed. If you have worked as an auto mechanic you should have everything you need.

The shifting fork (or fan as Peerless calls it) moves a collar back and forth along the intermediate shaft and connects the right or left bevel gears to give forward and reverse. Peerless uses a set of keys to lock either or none (for neutral) of the gears to the shaft. From there power goes to thru the differential and to wheels.

Could be broken keys or gears, but likely to be gummed up with grease that has hardened preventing collar and keys from moving freely. Unfortunately, Peerless uses a Bentonite grease which is the dirtiest, most staining substance ever invented. Make sure you spread plenty of newspapers and wear clothes you are prepared to throw away. After you thoroughly clean everything, and dry fit to ensure everything is working right, you need to repack with with the Bentonite. Figure $15 to $20 for a 32 oz tube.

You have a 910 series Peerless transaxle, and suggest you buy or borrow a copy of Tecumseh/Peerless 691218 Manual. I won't open a Peerless up without printing out the pages of the machine I'm going to work on. The other alternative is new transaxle, but they are about $500 outright, and most mower boneyards know they have you by the short hairs and want $150 to $200 used.

ggoyeneche.....Thanks for your insight into the problem. I'll get a printout of the gearbox on the rider, and get started. Hopefully, it is just gummed-up inside. I did actually get the rider to go to neutral after I tried to move it. I had jacked up the rear of the rider, and was pulling it to a different location, and when I let it off the jack, it was in neutral. Never did get it to reverse gear. It did, however, go to forward with the shift lever. Thanks again. David.