I am 17 yrs old and me and my dad own a 49 Willy's jeep. We are having trouble out of the transmission. It will jump out of 1st gear while driving. Also it will grind gears when downshifting from 2nd to 1st. You have to come close to a complete stop before it will downshift without grinding. I have read some posts about similar problems and people have mentioned the synchro or forks. Any advice or solutions are appreciated. Thanks!