1994 4.0 4X4 auto. will stay in 2nd gear even under very light throttle until I totally get out of throttle, then it will shift into 3rd. All other shifts are fine. It just started today. 173,000 miles. Any help greatly appreciated!

 

Check the vacuum line to the modulator for leaks and maybe replace the modulator itself.

 

That's being done right now. Thanks.