1994 GMC Sonoma Owner's Manual - Page 233

While reassembling the air cleaner assembly, ensure that the cleaner air cover tabs are fully inserted into the slots in the air cleaner and the housing PCV air tube is properly seated in the lefthand valve cover. when to replace the air Refer tothe Maintenance Schedule to determine filter. See "Scheduled Maintenance Services" the Index. in NOTICE: If the air cleaneris off, a backfire can causea damaging engine fire. And, dirt can easily get your engine, which will damage into it. Always have the air cleaner in place when you're driving. Automatic Transmission Fluid When to Check and Change A good time to check your automatic transmission fluid level is when the engine oilis changed. Refer to the Maintenance Scheduledetermine to when to change your fluid. See "Scheduled Maintenance Services" in the Index. How to Check Because this operation can be a little difficult, may choose tohave this you done at aGM dealership ServiceDepartment. If you do it yourself, be sure follow all the instructions here, you could to or get a false reading the dipstick. on 6-15