On a car with a dipstick, check automatic transmission fluid with the engine running at operating temperature, on level ground, with the parking brake on and the selector in Park: pull the dipstick, wipe it, push it back in fully and pull it again to read it. Haynes says healthy fluid is red or light pink; dark brown, burnt-smelling or cloudy fluid means a change is overdue. Many newer transmissions are sealed with no dipstick, so check your manual first.
How do you check the level?
- Confirm whether your transmission has a dipstick. Haynes’ example is the 2019 RAM 1500 Classic, where the 6-speed has a traditional dipstick and the 8-speed is a sealed unit with no dipstick that Ram positioned as a lifetime fill.
- Run the engine to operating temperature, on level ground with the parking brake on and the selector in Park.
- Locate the dipstick (often toward the rear of the engine bay with a brightly coloured handle), pull it out, wipe it clean, reinsert it fully and pull it again for an accurate reading.
On a sealed unit, Haynes says the check means removing a fill plug on the side of the transmission at a specific temperature range, a job that needs the right guidance. The procedure differs by car, so use the manual for yours. This guide is for one truck, so treat the steps as an example.
What does the colour of the fluid tell you?
- Red or light pink: healthy.
- Dark brown, a burnt smell, or cloudy or contaminated: a fluid change is overdue.
What are the warning signs?
Haynes lists delayed or sluggish gear engagement, shuddering or hesitation between gears, a burnt smell from under the hood after extended driving, fluid spots under the vehicle and the transmission warning light. See automatic transmission problems.
How often should you check and change it?
Haynes’ maintenance schedule says to check the automatic transmission fluid level every 3,000 miles or 3 months, and to check or change the fluid and filter every 30,000 miles or 30 months. Your manual may say otherwise; see our car maintenance schedule. The guides we read do not give a price, so we do not state one.
Frequently asked questions
Why does my car have no transmission dipstick?
Some transmissions are sealed. Haynes’ Ram example says the 8-speed has no dipstick and is positioned as a lifetime fill.
Should the engine be running when I check the fluid?
For the dipstick transmission in Haynes’ example, yes, at operating temperature. Check your manual.
Sources: Haynes, “How To Check Transmission Fluid Level On A 2019 RAM 1500 Classic” (March 2026); Haynes, “Complete car maintenance schedule” (May 2025).
