hi when should i change my transmission fluid i have a 05 2500 cummins automatic and never changed the fluid i have 87,000 on it and should i use amsoil i use it in the engine

 

Amsoil makes an oil that is ATF +4 compatible. I don't use it, but I've heard nothing but good things about it. The fluid is supposed to be changed/ new filter every 30,000 miles and the bands are supposed to be adjusted as well.

 

is this something i can do or do i need to take it to a transmission out fit

 

You can do it yourself I have done it before.... I'm trying to find a DIY on it but i can't locate it here...