I have a 93 F150 m5od that will stick in gear,last time it did that I removed top cover and found the shift rail had pushed the rubber plug on the front of the housing out.I put the plug back in and slid the rail by hand and again it pushed the plug out. Is that what could be causing it to get stuck in gear?

 

Your 1-2 shift fork is most likely worn so it slips out of its groove and flies so far out of place that the rail pops out the plug. I built mine up with my welder.

 

Thanks, I will take a look at that.

 

Thats what happens to these transmissions. My dad had the shift fork replaced at 130,000 miles... (1989 F-150 4x4 300/M5OD R2)