Ok i have a 95 suburban, just had the tranny replaced. (by aamco). about 200 miles ago. truck was parked in my parking lot letting it run while i hooked up the system. I currently have the fans converted to twin 1650 cfm electric fans, with a thermostat set at 160. Truck never got over 210 degrees. Got a afe intake, ssd chip"80hp". stock exhaust except the muffler. no major mods. could it be a bad selonid? If so its covered under warranty until next year. :(

2-3 solenoid may be.
does it shift after 50 mph if you floor the accelerator ? only when you drive it gently ?
Does you speedo needle goes jumping up & down ?

If so, you may check your speed sensor too.

No the needle stays their. but if i let off the gas the rpms drop. i have to stomp it and let rpms builld untill i get back to 300 to allow the truck to get power to the wheels