Skip the auto shop - Our mechanics make house calls

Q: How do you accurately check your automatic transmission fluid? Hot, cold, running, put all gears through, then check?

asked by on

transmission fluid check, see above Thanks

A: Typically, the fluid level is checked both ...

Typically, the fluid level is checked both hot and cold in order to provide a cross check. Checking initially when cold is easier as you are not hovering over a hot engine holding a hot dipstick. Basically, on a flat level surface, start the vehicle’s engine and immediately run through each gear, pausing just momentarily.

Finish with the car in "Park" and leave it in "Park". Withdraw dipstick and wipe it clean with a LINT FREE cloth (lint and dirt causes problems in transmissions). Reinsert the dipstick after you have wiped it and upon withdrawing it. See if the fluid level is within the cross hatched area marked below a "C" (for cold).

Sometimes you have to look at BOTH sides of the dipstick in order to gauge the level. If the level is in the "C" area, you are likely OK, but to be sure, drive the car for about 10 miles and re-check the level, this time looking at the cross hatched area marked below the "H" (run through gears as before, and leave in "Park").

If the fluid level is OK when cold, it should also be within the cross hatched area for "H" as well. The reason for checking when both hot and cold is transmission fluid expands as it is heated. Note that if you drive the car at highway speed for a long period of time and then attempt to check the fluid level "hot" after that you WILL get a false reading (the fluid level will appear "high", when in fact, it is perfectly OK). So, when checking if it’s hot, you can’t do that check if you just drove 50 miles across the desert because the fluid will have expanded. Transmission fluid expands and keeps expanding the hotter it gets. Dipsticks are calibrated to "normal" hot operating temperature (i.e., the 10 mile suggested drive; longer in winter). If the transmission fluid has been in your vehicle for more than 100,000 miles, change both the fluid and the filter, which maintenance will help promote the longevity of your transmission. Modern synthetic transmission fluid of the right type is recommended. If you are in need of a transmission fluid service, a certified technician from YourMechanic can come to your car’s location to perform this.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Engine temperature goes up when I run air

I have seen this issue before. When you turn on your air conditioning, there is a part called a condensor that sits in front of the radiator that gets very hot. The condensor looks similar to the radiator and actually...

Q: What Does Transmission Fluid Do?

Modern automatic transmission fluid (ATF) typically contains a wide variety of chemical compounds intended to provide the required properties of a particular ATF specification depending on the manufacturer. Most ATFs contain some combination of additives that are required for there...

Q: Temperature Gauge

With most any other vehicle, your diagnosis would be dead on, congratulations! In your case, the problem is most likely the thermostat. With this Audi engine, the Audi engineers were more clever, there is only a single coolant temperature sensor,...

Related articles

How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.