1995 GMC Yukon Owner's Manual - Page 304

The engine oil filler cap is located on a filler tube at the front of the engine. Just fill it enough to put the level somewhere in the proper operating range. Push the dipstick all the way back in when you're through. What Kind of Oil to Use Look for these two things: CF-4/SH CF-4/SH is the best oil for your vehicle. However, if you can not find CF-4/SH oil, you may use CF-4/SG or CE/SH orCE/SG oil. These may be listed as shown or in reverse order, for example SH/CF-4. Other letters may also be listed, such as SH/CD. CE, CF-4. These letters show American Petroleum Institute (API) levels of quality. NOTICE: If you use oils that don't have these designations, you can cause is engine damage which not coveredby your warranty. 6-22