Hey…
How often should you change the gear oil in your manual transmission and differential?
I am trying to keep track of when to change the GL4 gear oil in my manual transmissions in my 60’s trucks and also the differentials. I tried searching the forms but came up short. I might not be searching for the correct words to bring up this information.
I think time intervals are more important than mileage because these trucks are not at work often and are not my daily drivers. Any help would be greatly appreciated.
Last edited by Bornco; 03/23/2026 4:57 PM.
