More Trans trouble, p1740 code, new owner, and more

Hi all, I'm new here, and appreciate any insights. Are there any transmission specialists in the group?

I bought a used 2001 Ram, 113k, 5.9l 4x4 with I believe the 46re auto. It drove well, had a receipt for all fluids ($900 worth) 10k mi. ago and had the features I was looking for. I love the simple straight axle and the ride, but I digress.

1 week later...mil...p1740. I used the ignition hack I got from your site, then I cleared it to see if it was maybe a mistake. The next day, p1740, 3000rpm on the freeway (wouldn't shift out of o/d) o/d light, and trans temp warning.

I read several sites and posts with no definitive answer. Took it to Dodge and they said Torque Converter wouldn't lock up, was bad, and the trans prob not far behind. They offered a 3yr 100k warranty if I had a MOPAR reman trans and new Torque Converter put in. I figured I had got a fair deal on the truck and that I would have to bite the bullet for the 3 g's.

1 week later it feels like the rpms increase (like slipping) on the freeway very occasionally. After alot of stop and go driving today, it slips when starting from a dead stop like if it had a clutch that was going out.

Did I get taken on the trans install? Could it be an issue with something simple like fluid level? Also started hearing a knock like a u-joint from underneath, possibly unrelated :4-dontknow: Thanks for your help, I really don't know Dodge's and otherwise love the truck.