Is this a rfe 545? I have a 2006 dodge ram 2500 2wd 5.7 gas 8ft bed. Thanks after 2nd gear it slips. If I manually shift to second it stays in second. If I reverse it delays, then clunks into reverse, also for sometime it doesn't want to shift out of park, so I turn it off in neutral and emergency brake.

 

Yes, that's a 545RFE. I'm not familiar with the gear flows in the transmission, but clunking and slipping is definitely an issue. I recall there was a solenoid or valve body issue with these, but I'm guessing if you did have that issue, its gone past that now to a hard part failure. Rebuild or replace is probably your only option now, fortunately its one of the most used Ram transmissions, so there's a lot of used ones on the market if you go that direction