in this 76 Mercedes 280c 114073 chassis. I have this 722.102 transmission . disconnected the kickdown rod, transmission didn't do anything. is this a sign transmission needs to be replaced? had a mechanic install new vacuum modulater valve. still stays in 2nd gear . will go up to 60 mph then surge . also secondaries in solex 4a1 carb doesn't open. will this affect the transmission not to shift into 3rd gear?