I got this 1/2ton '90 Sub last month for $500 w/350 700R4/NP241 ,the PO said the rearend was bad. Sure enough the pinion on the 10b had a broken tooth. The driver side rear axle bearing had run down and ate the bearing surface on the shaft. What I don't know is the manufacturer of this diff. These pics are with the center pin out, the large rectangular hole is where the pin slides out and one end of the pin is the same shape as this opening. The axles are 30sp and the RPO codes show no factory locker(G80).