The easy way to boost differential performance and longevity
They’re the Trojans transferring torque to the drive axles of most rear-wheel drive cars, bakkies, vans, 4x4s and SUVs but more often than not, regular servicing of differentials, aka ‘diffs’, doesn’t happen. OEMs generally recommend diff oil changes around every 100 000km. 
Your workshop can capitalise on this servicing oversight by offering a ‘Diff Care’ service that will prevent premature diff wear or damage and ensure smooth driveline performance – benefits your customers will greatly appreciate. 
Follow these easy, cost-effective steps... 
Get the right tools and consumables from 
• Tools: Socket set, torque wrench, flathead screwdriver, pliers, oil transfer pump, plastic scraper, oil drain pan. 
• Consumables: RTV Red Gasket Maker, Gear Oil, Limited Slip Diff Additive [if applicable], Transfer Pump, Brake Cleaner, Paper Towel. 
To the task... 
• Locate the filler plug and loosen it to ensure it hasn’t rusted itself in permanently, preventing you from refilling the diff with oil. Once safely loose, refit the filler plug.• Place the oil drain pan under the diff.
• Commence loosening the diff cover bolts, leaving in the uppermost bolt, to allow the oil to drain out without splashing you and your workshop floor. 
• Now pry the diff cover loose with the flathead screwdriver to allow the oil to drain out completely. 
• Remove the top diff cover bolt and remove the diff cover. 
• Clean out the oil from the diff cover using paper towel and brake cleaner. 
• Clean any gasket material from the diff cover using brake cleaner taking care not to scratch any grooves into the gasket surface area. 
• Now clean the diff housing mating surface using a plastic scraper and paper towel soaked in brake cleaner. 
• Make a new gasket with RTV Silicone Red Gasket Maker. Cut the nozzle to the desired thickness [approx 7mm] and create a continuous bead of RTV around the diff cover mating surface. 
• Allow the RTV to dry a little for 15 minutes. 
• Refit the diff cover, inserting the top and bottom bolts first and gently tightening them by hand. Fit the remaining bolts. Tighten all the bolts lightly in a star pattern. 
• Allow the new seal to set for 60 minutes. 
• Torque the diff cover bolts to the specified setting. 
• Remove the oil refill plug and refill the diff housing with gear oil [e.g. 80W90 GL] using the transfer pump. Once oil starts flowing from the refill hole, you know she’s full. If it’s a limited-slip diff, don’t forget the additive. 
• Refit and torque the filler plug and it’s job done. 
Bottom line – changing diff oil is neither expensive nor labour intensive and best of all, the long-term value of regular diff oil servicing will make a genuine difference to the motoring experience of your customers!