1997 ram 1500 4x4, 156,00 miles, 46re auto trans. I got trans code for governor pressure sensor and I replaced that and solenoid. Fluid was pretty bad and thick and dark, sludge on bottom of pan and filter bad too. Cleaned and changed all that properly and filled with ATF 4.I did not flush, just dropped pan and drained that. Check engine light went off by itself and I could feel improvement. It does, however,now make a metallic popping or pinging or tapping noise when driving cold. It seems to come from underneath and from trans pan area. It happens only when driving and accelerating when cold. I've revved engine in park and no noise. It is sometimes one to three consecutive pops/pings/taps but it can be up to 5-6 in rapid succession. It stops when engine is at full operating temp. Double checked fluid level and it is fine. It did not do this before. Any ideas anyone? Thanks for any input. I like this truck and I like this site, thanks again!:4-dontknow: