"I've owned this tractor nearly 32 years. Wheel horse started using 2-cylinder Briggs and Stratton 16 horsepower 40 CI engines in 1982 due to problems with the Kohler K17. The Briggs and Stratton 16 horsepower has been just a great engine (3,200+ hours). I work this tractor very hard (move snow, cut lawns and fields), however I have changed the oil every 12 to 15 hours of use. Last month someone who will remain unnamed (not me!) put 35-40 hours of cutting fields on the GT 1642 without checking the oil level. I'm installing a cast iron Briggs and Stratton 18 horsepower Vanguard at the end of this week. I think this tractor will be good for another 30 years. P.S. I drain and replace the transmission oil every 3 or 4 years and have since it was new. "