When you release the door from the track it should go up and down with
equal force, if not the spring is out of adjustment. It is best to have
a pro do it as it can harm you bad if you dont know what you are doing.
WD 40 is not a lube , I have a 50 yr old door that gets grease in
bearings and oil on chain and hinges, WD 40 actualy washes oil off, it
is a very temporary lubricant, maybe 1 month.