07 Sierra 3500 HD Cab and Chassis Dual Tank question

[JohnWicked710]

As the title says with the addition it is a 6.0 Gas motor. I can't find any information on dual fuel tanks. The rear tank is not sending communication to the front fuel tank and I can't figure out why. I believe I will need to replace the fuel pumps/sending units for both tanks. If the back one is going bad, I figure I might as well replace the front one too. But here is the interesting part. I dropped the rear tank and pulled out the pump and it seems to be for a different vehicle based off of the part number I read on the underside of the pump. When I try to look up the pumps on the GMC Parts website all I see are single tank systems and I am uncertain of their compatibility. Anyone able to provide advice?


EDIT: I think I found the proper fuel pumps. The bosch website was the only one I could find that even remotely references primary and auxiliary fuel tanks. After putting in my trucks VIN I got these 2 bosch part numbers: 67781 (Primary Pump) and 66025 (Auxiliary Pump). I would just feel much more confident seeking these out and purchasing them if I got a second opinion. Thank you in advance for any assistance. 

Edited May 25 by JohnWicked710