my car has 29k miles. when I change transmission oil ?

Most manufacturers recommend that manual transmission fluid be changed every 30,000 to 60,000 miles. Under heavy-duty use, some manufacturers suggest changing transmission fluid every 15,000 miles

Do not go by what the owners manual suggests. Some say as high as 90K miles. The guy I graduated from high school with took over his dad's tranny shop 40 years ago. He suggested I bring him my vehicles every 40 K (if less than what the manufacturer indicates) along with a hundred dollar bill, and he would change the fluid and filter Well, my 96 Explorer is still ticking along smoothly at about 300K.