I guess it would depend on the supplier. When I was still turning wrenches we used a local shop for trans. rebuilds and they didn't paint them...after a while we switch to Jasper reman. transmissions. Sometimes Jasper left them natural and sometimes we got them painted a gray color.
There's really no need to paint aluminium I think.
However, be wary of those "spray can" rebuilds where some shops take a junkyard piece, clean it up, and then give it a coat of paint to make it look new and then charge you accordingly
I really think its the same tranny 99.9% positive. But I bring it to a tranny shop wed and we will find the truth. I would think that paint retains heat. And please correct me if I am wrong but I thought heat is one of the top killers of trannys?
It's too bad you didn't copy down the casting numbers of the transmission (who would think to do that anyway?) That way you would 100% know if it is the same transmission.
Yes heat does kill transmissions, but a coat of paint isn't going to hurt anything. I mean they paint the engine right? A good auxillary transmission cooler in circuit with the factory cooler will keep the transmission happy.
One Dodge dealer I do know gives the owner a choice of either having their tranny rebuilt(quite a bit cheaper) or a completely new dodge tranny with a better warranty. This is after the factory warranty was out.