Driveline noise?? Doesnt sound good.
 

The other day we noticed a squeeky noise coming from under the truck like a U-joint or carrier bearing, well we got under it and the U-joints and carrier bearing look good. We drove it around some more to get another take at it and it only squeeks in OD when you decel. When you drop it down into 2nd or 3rd it will not make the noise, we tried every combo of rpm and backload on the motor, no squeeky sound.

Im wondering if we hurt a bearing in the OD unit or something, has anyone ever heard of such a thing? I did get a P1765 code that I have never seen before, I read that as (tranny 12 volt supply relay control circuit) we did get other codes but they seem unrelated to the problem. This truck always has codes that come and go as they please.(Its the 2wd 1-ton)

Any ideas?

sounds like you might wanna check the od unit out, there is a bering that is used in the od that applies the od clutches. it can wear ir even bust and if it does it can cause a few major problems. you can pull the pan to check for metal or pull the od housing and check it.

Yea, I'm pretty sure its in the OD unit. It doesnt seem like a big deal to get it out and take a look.