Definition of precipitate. 1  1 : a substance separated from a solution or suspension by chemical or physical change usually as an insoluble amorphous or crystalline solid. 2  2 : a product, result, or outcome of some process or action.
Oftentimes, replacing a transmission solenoid will take no more than 2 hours, and repair shops on average charge $60 to $100 per hour for labor, not including cost of parts (a replacement solenoid should cost you no more than $200) or shop fees.
If it were my motor, I would change it at your 70 hour schedule or wait until 100 like the manual says. I have Caterpillar diesels in my offshore boat and the oil change recommendation is 200 hours. However, we change the oil as soon as it is convenient between fishing trips after we reach the 100 hour mark.