From Jalopnik · B. L. Johnson · · 1m
Transmission Fluid vs Hydraulic Fluid Differences
Why transmission fluid isn't interchangeable with hydraulic fluid despite both being fluids.
In brief
Why transmission fluid isn't interchangeable with hydraulic fluid despite both being fluids. Using hydraulic fluid in transmissions causes clutch slip, shifting problems, overheating, and gear wear. Originally reported by Jalopnik.
What transmission fluid is
Transmission fluid is a specialized hydraulic fluid for car transmissions.
Why they're not interchangeable
Hydraulic fluid shouldn't be used in transmissions due to different additives and temperature requirements.
Transmission fluid additives
Transmission fluid contains additives to control friction across temperatures and prevent rust.
Temperature differences
Transmission fluid works in extreme heat and cold with specific friction control additives.
Transmission fluid types
Manual and automatic transmissions use different fluids with varying viscosities and additives.
Automaker-specific fluids
GM uses Dexron VI, Ford uses Mercon, Chrysler uses ATF +4 for specific transmissions.
Consequences of wrong fluid
Using hydraulic fluid causes clutch slip, shifting problems, overheating, and gear wear.
Here's the gist
Using hydraulic fluid in transmissions causes clutch slip, shifting problems, overheating, and gear wear.
