I see a lot of post on how to change old transmission & differential oil.

My 53 Chevy set up about 20 years. Is changing the oil necessary or should it just be topped off & driven?

Could draining & filling with new oil start some leaks ? The truck has a new 235 & new clutch.

I have driven it 100 feet several times over the past 4 years that work has progressed with no apparent problems but now I would like to start driving to the mail box & back every day about a 1/2 mile.

Thanks, Kelly

53 3100
http://www.cravy.com/53-3100/LadyAfterRats.jpg