I know this isn't a Dodge forum but........After changing the fluid and filter in my Durango something went wrong! Between the 1-2 shift it surges and it won't go into Overdrive. I've changed the filter many times before and No Problem.
518's use a solenoid for OD and lock-up and I believe somewhere around 96-97 they all went to electronic governors instead of hydraulic. I'd check the case connector on the out side and if you have to drop the pan again and double check that the wiring hasn't been damaged and make sure the governor pressure solenoid is hooked up. If all else fails take it to a shop it may just need some solenoids. I'd get it shift kitted also. Good luck
Just a wild shot in the dark, but my neighbor has a Grand Cherokee, and he went to change the trans fluid, and bought it at the dealer. He was told that they are very sensitive to the type of fluid. I think the Durango has the same trans. They also vary in fluid requirement from year to year.
My F150 was also very sensitive to fluid. LubeGard helped it, and Mercon 5 fixed it!
I had the torque converter shudder, sort of the opposite to slipping, though.
Did you use the Mopar ATF? Dodge / Chrysler / Jeeps vehicles use a special ATF? Just making sure that you did that. If so, it sounds like you car is in 'limp' mode and you should take it to the stealership to have the codes pulled and find out what is wrong
A product made by Lubegaurd converts Dextron III into Mopar 7176. In most cases not adding it to dextron III may cause shuddering on the shifts. If it's not been added you should.