Eaton 18spd upgrade question?

He was definitely looking for ideas. Said driveline was all good and no odd vibrations or anything. Didn't hear Temps. He hauled cows, which is usually heavy. And cows can really make the trailer shift hard if not driven smooth, ive heard of guys knocking drivelines out but again not usually in high gear

 

It is probably tearing the teeth off direct (3rd in the main box). It is used for every single gear, not just the top gear. Driver abuse on the low end can easily cause it. Driveline vibrations usually explode the syncro.

 

No he said he was just losing 17 and 18. Nothing else, he was still running in direct after losing overdrive while under a load