Noise from rear diff?

[last-442]

Excuse my ignorance but, is the G80 an option code for the posi or is that the model of the rear-end?

Does anyone have a breakdown of what the option codes relate to?

Thanks

 

[last-442]

Disregard my previous entry, newbie mistake.

Good site for RPO codes: http://www.gm-trucks.com/rpo-code-lookup/

Not that this isn't a good site keep up the good work.