I replaced the original 4-Speed with over drive manual tranny two years ago. But now it has started giving me a problem[>:]. I can not get the gear selector to stay in overdrive.[:@] It began about a month ago that when i was going up an incline or if I let off the accelerator a little it would come out of gear. Now this weekend it came out and woould not stay in unless I held it there. I have checked the fluid and it is full.

Any ideas? I have something about synchronizers?

Thanks for any help