Flush or drain and fill?

Drain and fill. GM and Honda bulletins say not to use flush machines; Honda's own 'flush' is three drain-and-fill cycles.

Can I use a universal ATF?

Only if the vehicle maker approves it. Hyundai, Honda and Nissan bulletins (each for specific models) name their own fluid and warn that others can harm shift quality or the transmission.

My car has no dipstick. Can I still do it?

The drain-and-fill, yes, with the measured amount back in. The level is set at a fluid temperature with the engine running and the car level on a lift, so in this guide a shop does that last part.

Will new fluid fix slipping?

No. A slipping transmission goes to a shop first.

Driveway Mechanic Series

How to change transmission fluid?

CHANGE THE DAMN TRANSMISSION FLUID.

Maker's fluid only, fill plug loose first, measure what drains, refill the same, set the level the maker's way. North American cars.

30 years fixing everything. Written by a tradesman, not a website.

Also covers:

transmission fluid change
drain and fill vs flush
how to check transmission fluid sealed transmission
cvt fluid change

The short answer

A mechanic's drain-and-fill guide: owner's-manual schedule first, maker-spec fluid only, fill plug loosened before draining, measured refill, dipstick and check-plug level checks at the maker's temperature, pan and filter where called for, and hard stops for burnt fluid and slipping.

What's inside

Read first: safety stops
60-second diagnosis
How it works
CAN I DO THIS?
SHOULD I CHANGE IT AT ALL?
TOOLS AND THE RULES
READ THE FLUID
DRAIN IT, MEASURE IT
SET THE LEVEL RIGHT
DROP THE PAN
DRIVE, RECHECK, RECYCLE
TEST, THEN BUY
WHEN IT GOES TO A SHOP
DON’T MAKE IT WORSE
KEEP IT SHIFTING
QUICK REFERENCE
PARTS & TOOLS
HOW WE CHECKED THIS
Job card + shopping list

5 step-by-step repairs
13 illustrated steps
6 parts and tools listed (tools with exact part numbers; wear parts matched by VIN or the old part)
Confirm-before-you-buy tests
Specs table, metric + imperial
One-page job card + shopping list
"Don't make it worse" page
Safety stops: when to call a pro

Look inside

Sample page 1 of the field guide: cover — cover

Sample page 6 of the field guide: Can I do this? — Can I do this?

Parts list (free)

Every part and tool in this guide, with fit checks and US stores. Tools have exact part numbers; wear parts are matched by VIN or the old part.

See the parts list

Change the Damn Transmission Fluid

Buy the guide — $11.99

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General information for the vehicles this guide covers. You do the work at your own risk; follow the vehicle maker's service information and the emissions and roadworthiness rules where your vehicle is registered. Car guide terms · Edition 1.0 · 2026-10-07