I was in the boneyard and saw a car with the GT4 rear axle code on the RPO sticker. I think it was an 86 T/A if that helps. I've never seen this code for a rearend before. Does anyone happen to know what ratio it designates, and if it was a nine or a ten bolt? Thanks.

 

GT4 = 3.73 ratio

 

Hmmmm, that makes sense. That's probably why I haven't seen that code too much since factory 3.73's are fairly rare. Thanks for the reply Rick!