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Automatic Transmission Fluid Check

From a cold start , how long or how far should a vehicle be driven before the transmission should be filled to the full hot mark ?

I don’t know if there is a rule of thumb, but I’d recommend about three miles after the temperature gauge has hit its normal mark.

As long as it takes for the trans fluid to be above 175 degrees. I would say a good 15 minutes of driving after the engine reaches operating temp. But depending where you live, this time of year that may not even be enough for the fluid to reach warm. Does this Jeep have a conventional dipstick?

Why not just check it cold and make sure it’s at the cold full mark?

My old GM had a cold mark. For hot you can drive it around for 2 days if you want. JK!

It has a dipstick & I just did a pan drop & added new filter & fluid . The fluid level is at the full cold mark now . My wife will be driving to work , about 50 - 60 miles round trip & I would like to run it long enough to top it off at the full hot mark .

When I was 17 I stopped at a station to have my fluid checked. The guy pulled the dip stick and said “you need to drive it, it needs to be hot”, and sent me off to drive it a little before I came back.

Check your owners manual though.

I usually drive 10 miles or so and when the engine is thoroughly warmed up the transmission fluid is likewise.

The last car we owned that had a transmission dip-stick, there were two marks

. One for Cold.

. And one for hot.

When the tranny fluid is cold add fluid to the cold mark…When hot - add fluid to the hot mark.

When I had cars whose transmission fluid could be checked, my wild guess was that 20 minutes of driving (ideally mixed city and highway) would be enough. I have no idea how accurate that actually is.

The full cold mark is more reliable than the full hot mark.

If I were you I would check it when your wife gets home after work. And even then it doesn’t need to be at the full hot mark, just between the full and low marks. Trans fluid expands when it gets hot. Fill it all the way to full on a cool winter day, and 6 months from now when you’re pulling a load up a grade the fluid will actually be over full.

I don’t recall which trans is in your Liberty, but many Chrysler transmissions don’t fare well with fluid over full.

Thanks guys , since it’s at the cold mark I’ll leave it & check it again when she get back from work . It should be hot enough then to get a good hot reading . It has the 42rle transmission .

After the vehicle was ran long enough to be thoroughly warmed up the transmission fluid was right on the full hot mark .

I’ll paraphrase, but our Dodge van owners manual talks about the heat of the dipstick and how uncomfortable it is to the touch to determine whether your transmission is up to temperature for the hot reading.

Is that “uncomfortable factor” something that can be accurately quantified?

Ever since running my motor bike in the winter when I was a kid, I have had no trouble handling hot stuff. If I do dishes, the water is so hot others can’t tolerate it. I rarely need pot holders. I attribute it to cold handle bars and becoming acclimated, or the nerve endings being shot. So yeah, it varies with the person.

For what it’s worth, when I checked the transmission fluid level on my previous car, the dipstick was pretty hot and it was near some other very hot parts. I eventually figured out that putting a pair of old socks over my hands and forearms was a good idea.