I’ve been searching all over the web for rpo codes to see what gears we have in rear end. All the lists I’ve found my codes DO NOT match a single one. Any ideas?
vin and everything is correct 1986 z28 with 305 155hp 4bbl. But I cannot match a single code for rear end out of any list.

 

Nevermind the highlighted code.....I was searching for the code on a buddies IROC when I found this

 

 

Rear axle RPO codes start with "G". Post up all the "G" codes on your SPID label, or however else you have them, and maybe we can tell you what it came with. Which may or may not be what you have now.

Most likely your car came with a 2.73 10-bolt if auto, or a 3.08 10-bolt if it's a stick. AFAIK no Camaros got the 9-bolt until 87; Firebirds started using it in 85 in certain applications, but by far not all of them.

Replace your rear end fluid. It needs it BADLY. I can tell by just looking, all the way at this distance, that your car hasn't had this important service done in DECADES, if at all. While you have the cover off, LOOK AT the parts inside it. Whatever is in there, is what you have, which may or may not match any "code" you may or may not have. PARTS tell the whole story. "Codes" are largely useless and irrelevant.

2.73 will have 15 teeth on the pinion and 41 on the ring (41 ÷ 15 = 2.7333333...); 3.08 has 13 on the pinion and 40 on the ring (40 ÷ 13 = 3.07692307692307692...) Other ratios can be readily calculated in the same manner, once you LOOK AT THE PARTS.

 

The name of the company Borg-Warner (and more recently calling itself BorgWarner) was/is NOT "Borg & Warner", incidentally. Although one if its predecessor components was in fact Borg & Beck. Not sure whose idea that was, to corrupt it like that; I guess, a classic example of why you can't believe everything you see on the Interwebz. Excuse me while I go have conjugal relations with a demon so I can catch a communicable disease...