1988 Ford Ranger A/T Transmission Will Not Engage Next Gear
 

My 1988 Ford Ranger Just Had The Spark Plugs, Wires, & Oil Change. Now When I Drive It I get to about 25 MPH at 3000 RPMs and the Next Gear Does Not Engage. Also I Hear What Sounds Ti Be Grinding Noises. All Help Is Wanted Thank You

Welcome to the forum

You have an A4LD automatic in a 1988 Ranger

It has a Vacuum modulator located on the passenger side of transmission
It has a vacuum hose attached that runs from there up to the engines intake manifold
Make sure its hooked up