How to Troubleshoot a GMC Transmission

The transmission in your GMC should last for at least 60,000 miles. However, if your vehicle was abused (driven harshly) or the transmission fluid levels were not kept at proper levels, then you may end up with a transmission that fails prematurely. This is true whether your GMC has a manual or automatic transmission. There are many warning signs that your GMC transmission is going to fail. You should troubleshoot the most common problems that can occur with both manual and automatic transmissions first.

Instructions

1. Start the engine of your GMC vehicle and let the engine warm up. When the needle on the temperature gauge sits in the middle of the upper and lower marks, the engine has reached its normal operating temperature.

2. Open the hood and pull the transmission dipstick out of the back of the engine. The dipstick will have a looped handle.

3. Check the transmission fluid level on the end of the dipstick. Transmission fluid is a special type of oil made for lubricating the gears in the transmission. The oil will be red in color for GMC vehicles. The transmission oil level should be between the upper and lower marks on the dipstick. If it is not, you will need to have the transmission filled with the transmission fluid General Motors recommends for your vehicle.

4. Check for a grinding sound when you shift gears. This problem indicates that the synchronizers or gear teeth are damaged and serious transmission servicing is needed by a professional transmission specialist.

Tips & Warnings

• For specific information about your GMC vehicle, consult the particular vehicle's manual (see Resources).

Resources

• themotorbookstore.com: GMC Service Manuals