94 c1500 transmission shifting problems

hi, I've got a 94 c1500 that has developed transmission problems after pulling a trailer from Illinois to Florida. Reverse is ok, speedometer works,brake lights work, but have to let off gas to get it to shift out of first and it feels like it goes into 3rd, has no overdrive any ideas on what's wrong? thanks in advance

hi, I've got a 94 c1500 that has developed transmission problems after pulling a trailer from Illinois to Florida. Reverse is ok, speedometer works,brake lights work, but have to let off gas to get it to shift out of first and it feels like it goes into 3rd, has no overdrive any ideas on what's wrong? thanks in advance

most likely this will need a rebuild. when towing did you use 3rd gear ?

if NOT then this would be why it will need repair. when towing or hauling loads in 4th the transmission temps rise very high.

speed over 70 mph is also not good.