5TH gear displacement

I have a 1997 Tacoma extended cab, manual 5 speed transmission with the 2FE engine. It has 120,000 miles on it. Suddenly when shifting into 5th gear it physically goes 3 or 4 inches farther up and to the right than it should and the shifter turns about an eighth of a turn counter clockwise. It will go into 5th however, it gets stuck there and is difficult to get it out but will come out with some grinding. Even though it goes into gear it definitely feels like something is wrong so I haven't been putting it into 5th. It will drive just fine in 1st through 4th gears. Before I take this to a shop I wanted some good advice on what it is so I don't completely get ripped off. I'm pretty well mechanically inclined so if it's an intermediate type of fix I can do it, however I'm not messing with any syncrose. Has anyone had or heard of this problem? Any Idea's?
Thanks

 

the shifter seat is toast in bottom of the shifter. Marlin crawler sells them for pretty cheap if I remember right, and they are a simple install. No need to go into the granny, simply remove shifter boots and its all right there. When I got my taco it was doin the same thing and new seat fixed it right up.

 

I would agree with what he said and try a new shifter seat. They are cheap anyway.

 

see this post: http://www.tacomaworld.com/forum/1st-gen-tacomas/341963-lost-third-gear.html

I had the a similar problem. new bushing fixed it, It wasn't that hard of a fix.