Not so sure about my sanity, hahahahahah.You da man! @LJE 's sanity is safe too!
The speedo correction box removal was one of the (many) poo-at-the-wall flinging ideas I had while @MongooseGA was troubleshooting the truck. It seemed like it would be weird to have an issue with the box that only caused the truck to lose 5th gear with no other symptoms, but I was trying to think of what in the world might be different about Gerry that was causing this issue to appear for what seems like the first documented time.