Transmission shift Celoniod ????

Friday I changed my Transmission Fluid, Filter, gasket ect.. and Saturday My service engine light came on. I used my scan tool and code PO753 came up - Shift celonoid A circuit- 1 of 2, does anyone know where to find these sensors and is it an easy fix, Truck is shifting fine and old fluid looked great, no flakes or crap in the pan.. :eek7:
99' silverado Z71 ext. cab Auto.
Thanks, Jimmy

1-2 and 2-3 shift solenoids are prone to getting bumped by the pan when changing the filter. (especially if you had trouble getting the pan clear of the exhaust) They are near the rear of the valve body. If your truck is shifting fine then I would reset the computer and drive it. If not pull the pan and check the connections @ the shift solenoids.

Thanks for the info, I will replace both of them at the same time as to not pick the wrong one and have to start over again (about $25.00 each at GM) You were right the pan was a pain to get off.. Once again thanks for the help!!!!
-Jimmy

When I had the fluid and filter changed on a 99 work truck, they either forgot to reconnect a wire in the pan or knocked it loose. Wanted to take off in 2nd gear. They pulled the pan again, reconnected the wire and problem solved.

Just a follow up, I dropped the pan and replaced Both Seloniods, once under the truck I could see one of the plugs came loose but I already had the parts so I replaced them. Easy fix.. Now it shifts much more smoothly and precise, best since I bought the truck!!
Thanks Gooseneck and Cliff,
-Jimmy

Good Job!