91 3.0 4x4 What is this?!

[EvilNavyGinger]

I have 3 parts trucks, 2 running. I have never seen this before. I know brake lines go in, thats about it. Mounted on the frame on the passenger side. Don't know if it works or what it does. There is an electrical line going to the rear diff.

http://www.mightyram50.net/vbulletin/attachment.php?attachmentid=28271&stc=1

[tortron]

Presumably the Abs pump
https://www.moparpartsgiant.com/parts-list/1991-dodge-ram_50/brakes_service/modulator_anti_skid_brake_system.html

[Chargerx3]

Yea, thats the later ABS BS.