|This is the pinion seal for the GM 8.5 rear. This seal fits 8.5 REARS from 1971 to 1997. Later versions of this rear are referred to as 8.6 and use an updated design of this seal, also the 8.5 FRONT uses a different seal as well and we have them ALL right here in our store. Questions? Concerns? Call TOLL FREE 1-877-614-GEAR.