I changed the oil in it today and it looked like it has not been changed in years. the oil filter was falling apart when we took it out. i checked for vacuum leaks today but i didn't see any or hear any. how do the transmissions normal shift in these cars? It seems like this one shifts real firm for the type of car it is. What controls the shift is it vacum or is it some thing else? What about vales is it common for a burnt valve in these cars. how do you check for chain ware what do you have to take apart? i do not know about the records but the maintenance booklets last serves stamp was at 90,000 miles and that was like 12 years ago. thanks for any help