How can you tell what auto trans is in my truck. I just purchased 2003 SO with 138000 miles it is a 3500 single axle... the guy I bought it from said it was replaced with 40000 miles on it and was upgraded to a different trans. How can i tell what it has in it....

 

Look on the side of the trans there should be a manufacturer tag on it, probably the left side.

 

I did look on the left side and didnt see anything...

 

what about right side?