Will the manual locking hubs off a 1984 GMC Suburban fit on 1986 Chevy with auto hubs?
No, manual locking hubs from a 1984 GMC Suburban will almost certainly not fit on a 1986 Chevy with automatic hubs. While both are likely to be using the same basic axle design (likely a Dana 44 or similar), the specific hub designs are different. The automatic hubs require a different mounting system and internal mechanism compared to manual locking hubs. You'll need to find manual locking hubs specifically designed for the 1986 Chevy's axle.