Have a 2000 ram 5.9L, already had the overdrive solenoid replaced but that did not correct the problem - the code is back. The rpm's surge aprox. 200-300 rpm when driving 50 mph+. The tach will jump up and down 200-300 rpm in O/D and 3rd gear. Has anyone experienced the same problem and figured out a cure??

 

Could be your torque converter. I too have the 1740 code(replaced solenoid) light went out but came back . I've been running it,I've experienced no problem such as surges.Your surges could be your torque converter kicking in and out(just a guess). good luck.