I have a C 10 with a 350 2 barrel(soon to be replaced) backed by a TH350. My transmission has always shifted perfectly and without hesitation. The fluid and filter has been changed within the past 6 months. After taking a trip that was over 100 miles in 80 degree weather, the transmission began to let 2nd gear rev up to nearly 4000rpm before shifting to 3rd under normal acceleration. This got progressively worse and now she will not go into 3rd gear at all. The fluid level is full and im really not sure what has caused this problem.
Could i have overheated the transmission? Shifting between 1st and 2nd is still perfect, but once it is in 2nd it stays. I dont know how this could suddenly occur but any help would be great.
thank you for the reply. one last question tho, while driving the truck down the road around 35-45mph she remains in second while applying the throttle, maintaining a 2800 or so rpm. If at that speed i let off the pedal it feels like she upshifts and the rpms drop to about 1500rpm. But the moment i reaply the throttle the rpms immediately climb to 2800 again. Do you still think a seal has failed not allowing enough fluid through or could you think of anything else? Just trying to troubleshoot before i resign to the fact i may have to send her out to be rebuilt.