Fully drains transmission oil cleanly by air pressure. Most draining methods use gravity, leaving up to 2. 6L of oil left in the system. Services Mercedes 722. 6 722. 9 Transmission. BMW 6HP 8HP Transmission. California Prop 65 - Warning, This product contains chemicals known to the State of California to cause cancer, birth defects or other reproductive harm. br Whether tuning up your 68 Corvette or changing the oil on a John Deere tractor, CTA can supply you with the tools needed to do the job.