Hi I have a 84 year model case 580e that wants to pop out of 4th gear under load. it seems the shifter is going all the way in. I ordered a service manual but it hasnt arrived yet.
If its a manual type transmission then likely worn shift splines, similar to this video. Also not having full engagement of them, like worn or bent shift fork, or other parts.
Thanks Chidog I will have to pull the cover of and look at it. Thanks for the Video.