1995 GMC Sonoma Owner's Manual - Page 232

Automatic Transmission Fluid When to Check and Change A good time to check your automatic transmission fluid level is when the engine oil is changed. Refer to the Maintenance Schedule to determine when to change your fluid. See "Scheduled Maintenance Services'' in the Index. How to Check Because this operation can be a little difficult, you may choose tohave this done at your GM dealership ServiceDepartment. If you do it yourself, be sure to follow all the instructions here, or you could on get a false reading the dipstick. NOTICE: Too much or too little fluid can damage your transmission. Too much can mean that some the fluid could come out and fall on of or Be hot engine parts exhaust system parts, starting a fire. sure to getan accurate readingif you check your transmission fluid. Wait at least 30 minutes before checking the transmission fluid level if you have been driving: 0 0 0 0 When outside temperatures are above90°F (32O C). At high speed for quite a while. In heavy traffic - especially in hot weather. While pulling a trailer. To get the right reading, the fluid should be atnormal operating temperature, which is 180°F to 200°F (82°C to 93°C). To check transmission,fluid hot:Get the vehicle warmed up by driving about 15 miles (24 km) when outside temperatures are above 50°F (10°C). If it's colder than 50°F (lO°C), drive the vehicle in THTRD GEAR (D) until the engine temperature gage moves and then remains steady for ten minutes. Then follow the check procedures. hot 6-14