Code 15 but...
 

Issue: transmission doesnt shift until redlined from 2-3rd. Speedometer doesnt work.
i have changed the fluid and filter in the transmission(42re) and the speed sensor on the rear output housing. No change. Any suggestions would be greatly appreciated.The codes 15 and 12 come up when i run diagnostic. Is there somethung else that would cause the 15 code to come up besides the speed sensor?

Dont know what would cause the transmission issue but the speedometer issue is probably the speedometer cable. Easy to replace and pretty cheap (25 ish bucks). Also it will help people if you have information about what year and engine cherokee you have.