As I was mowing my lawn, I backed up and when I put John Deere Sabre lawn tractor, (model 15 1/2 1642 automatic HXD 1698A) in gear to go forward I heard a grinding noise if I attempted to go forward with any speed. After putting it up on blocks to inspect, I started the mower and it ran just fine when in gear. However, as soon as I took it down and attempted to move forward, again the grinding. I can mow at a very low speed which will probably mean taking 6 hours to do a 2 and half hour job.

Hi,
I cannot say positvely where it is, but I need the serial number. Probably under the seat, maybe in the battery compartment, or on the rear frame, or on the left side frame near the engine. Those are in descending chances.
I know these machines, but Deere will change without notice and no dealer, much less anyone else will know until after the fact.
Peace,
Clarke

The serial number is GXSABAR016240. Any information is appreciated.

Hi,
I do not mean to sound condescending, but what have you towed that you should not have?
Grinding sounds are usually provided by two causes; the input bearing the transaxle (you could wobble around the sheave/shaft with the park brake on) or the differential (felt by putting on blocks and turning one wheel while holding the other.)
Neither is good and involves a teardown of the transaxle. I would bet on the differential, and that means heavy towing.
Peace,
Clarke
PS Thank you for the serial number!

I have not towed anything, my property is not very level, actually I bounce around a lot. Yesterday priced a transaxle and at about $600 with the mower being 12 years old as it is, I think I'd rather put the money towards a new mower.

Thank you for the information.