shifting problems after oil change

[lzford]

I traded some work for a well rode 98 blaster rebuilt the top end and every bushing bearing and ball joint finally got to take it for a ride but to no surprise it wouldn't shift any higher than third gear. read every post I could find on this problem allot of people were having trouble after an oil change. so after splitting my case I learned that if you overtighten the drain plug it jams the shift cam

 

[Awk08]

It will also do that if its not the original stock length drain bolt,
( hardware store bolt or some of the magnetic drain bolts with the extended magnet)
and possibly if the washer is missing.

 

[Racer51]

a magnetic one will do it itll come off and get lodged and will cause it to not shift. also some oils rarely cause it to not to cause of something about friction modifiers. but i dont know ive never had that problem with any oil ive used. So my money is on longer drain plug and or magnetic drain plug cause ive had both happen to me at the same time