1998 ford explorer shifting problems?

Question

My ford has a automatic transmission. While it is shifting into fourth gear it races up a second then goes into fourth , then overdrive. Checked fluid not burnt, and level. All other shifts are good , it just started this yesterday. never had one do this. computer? Does this year have a vacuum solenoid or chip, or something else?

Answer 1

TRANSFER CASE  TRY IN 4X4 LOW

Answer 2

My 1998 explorer has a noise comming from the transmission when I am coasting, also it now will not go into reverse. makes a whiny grinding noise. What could cause this?