# Transmission Fluid vs Hydraulic Fluid Differences

> Why transmission fluid isn't interchangeable with hydraulic fluid despite both being fluids.
- Title: Transmission Fluid vs Hydraulic Fluid Differences · Jalopnik
- Summary: Why transmission fluid isn't interchangeable with hydraulic fluid despite both being fluids. Using hydraulic fluid in transmissions causes clutch slip…
- Keywords: transmission fluid, hydraulic fluid, atf, dexron, mercon, atf plus four, automatic transmission, cars, culture, Transmission, Fluid, Hydraulic
- Source: Jalopnik — https://jalopnik.com/2280333/differences-between-hydraulic-transmission-fluid-why-they-matter
- Author: B. L. Johnson
- Published: 2026-10-11T09:25:00+00:00
- Read time: 1 min
- Topics: transmission fluid, hydraulic fluid, atf, dexron, mercon, atf plus four, automatic transmission, cars, culture
## 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.
## Key takeaway

Using hydraulic fluid in transmissions causes clutch slip, shifting problems, overheating, and gear wear.