20890 ? Customer Advisory Letter. On these dual rear-wheel vehicles, the rear-wheel lug nuts and studs may be damaged during the removal and attachment process. Damaged lug nuts and studs could result in a loose or detached wheel. This condition may be noticeable during normal vehicle maintenance and torque checks. Customers are being advised to immediately inspect their vehicle's rear-wheel lug nuts and studs for damage and replace them if necessary. Customers are also being advised to continue this inspection as part of normal vehicle maintenance and that replacement lug nuts and/or studs are available from their local GM dealer.