Overfill of Automatic Transmission

jerry_njApril 9, 2007

What are the problems/risks of overfilling an automatic transmission (Dexron III). The problem resulted when I got a low hot reading, added about 3 oz of fluid then checked later. It now seems to be overfilled, but it couldn't be more than an oz or two.

Thank you for reporting this comment. Undo

3 oz should have no affect, transmission fluid expands a good bit when it comes up to full hot temp and the systems are designed to leave room for that expansion you should be within the design specs if only 3 ozs over full. Unless this is a teeny tiny trans on a little bitty bug car that only holds a couple of quarts of fluid total or sumpin. Probably 90% of the vehicles that go thru the quick oil change places are over juiced, those high school kids that work there could not care less lol

    Bookmark   April 11, 2007 at 11:23AM
Thank you for reporting this comment. Undo


Thanks for the response. The transmission is in at 2004 Forester, so the transmission isn't small.

I had checked the transmission hot as part of my oil change. It read a little below the full for hot (but how hot is hot?), anyway I decided to add just a little, in fact the 1Q bottle of Dexron III I had on hand was almost empty and I used only a part of that, trying to be careful not to overfill. I put a oz or so in and check, still a little low, put in another oz or two and quit. Later I check it cold and it read overfilled for full, way over the cold range. I don't see any fluid on the floor of my garage, nor do I smell anything unusual when driving the car. I'll check again but think I must have had a some problem with proper cleaning of the dipstick before making the reading.

    Bookmark   April 11, 2007 at 12:09PM
Thank you for reporting this comment. Undo

Ive been to another forum and there are different problems about overfilling the transmission.. It depends from tranny to tranny.. from a tranny chop FAQ: they say, it wont hurt the transmission though it might cause some parts to move and become aerated.. And of course leaks that are not really so ordinary would be visible..

Here is a link that might be useful: Automatic Transmission Solenoid

    Bookmark   November 12, 2010 at 10:20PM
Sign Up to comment
More Discussions
Blown tire on a dying car........
Well, in my other post I talked about how my transmission...
Car suddenly accelerats
This morning my wife was driving our 2013 Chrysler...
Brake fluid flush
I've had new brakes installed in the past. However,...
Cost to replace a 99 Buick head Gasket
My grandson 99 Buick blew a head gasket after the thermostat...
Cost to Replace Car Battery?
DH took our 2005 Jaguar X-Type into the dealer for...
Sponsored Products
Modern Chrome Exposed Thermostatic Shower Faucet Valve Dual Control
Hudson Reed
ALLCLEAR NATURALS™ Concentrate Outdoor Lantern Refill
$25.00 | FRONTGATE
Kelvin LED Presence Detection Table Lamp
MTI Basics Bathtub (59.75" x 35.75" x 19.75")
Modern Bathroom
Jura Impressa F7 Automatic Coffee Center - 13709
San Remo Sleeper Sofa and San Remo Sleeper Sectional Sofa Chaise
Italy Design
Flood Lights. 270-Degree Outdoor Rust Motion-Sensing Security Light
$49.97 | Home Depot
Graff | Terra Bidet Faucet Set
$261.75 | YBath
© 2015 Houzz Inc. Houzz® The new way to design your home™