2013 3.7 2wd 6R80 Issue/Vibration
 

2013 3.7 2wd 120,000 miles. Leaving work I hopped on the highway and as soon as I hit 60 mph I got a pretty stout vibration in the seat. There were no issues prior to this point. I immediately pulled over and checked my tires assuming I had one go out of round or something similar. No issues there so I limped it home and kept in under 60mph. The vibration is only at 60 mph and not load dependent. I popped it in neutral at 60-65 and the vibration persists until going back under 60.

The next day I got it on a lift, and checked the entire driveline. U-joints, slip yoke, carrier bearing, driveshaft and rear end are all fine. The rear seal on the transmission was leaking slightly with a decent amount of fluid around the base. I changed the seal but notice some up and down, side to side (not spin) play in the output shaft. I'm assuming this is the source of the vibration. If the bearings around the output shaft are worn it would make sense and it will bang around and knock the crap out of the seal until it leaks. After putting in the new seal the vibration seems "muffled," less violent, but its still there, solidifying my thoughts.

Has anyone else had this issue? What did you do to fix it? I've been looking at used transmissions but so far the one I found had more play in the output shaft than the one in my truck so I rejected it. May have to just pay for a rebuild I guess.

I contacted a dealer and they said there should be no play. I tried to contact ford, but they were useless.

Transmission shop
 

I’d find the transmission shop your local hot rodders use and ask them.

With any luck the tail shaft bearing is a bushing pressed in behind the seal and can be easily changed.

From everything I've found the bearing is pressed in. However, it doesn't appear that it can be taken out without first removing the output shaft from the top. Can't get a bearing pulling in there otherwise.