I have a 1998 Ford Ranger XLT manual 5 speed. I recently replaced the vacuum hubs and vacuum lines and had no trouble. Today I was driving on the freeway and the light on the dash for 4WD high and 4WD low flashed about 5 times and then the 4WD wouldn't work. I'm not sure where to even start on the diagnostic for this problem.
Today I was driving on the freeway and the light on the dash for 4WD high and 4WD low flashed about 5 times and then the 4WD wouldn't work.
Why are you using 4×4 on the highway? Was it dry pavement? If so, your transfer case is probably a wreck. 4×4 is not AWD. It's made for off reading, not dry pavement.
You clearly messed something up with the new vacuum hubs and lines.
I was just driving and the light started flashing,
The way you phrased it, it sounded like you were actively driving in 4x4 when the flashing light started. That is a really buggy design on Ford's part. You would have been better off completely bypassing the vacuum hubs and installing manual hubs. The system is computer controlled. Providing you didn't have it engaged, there is an electrical issue somewhere.
True, I'm thinking about just changing out the transfer case and motor.