Proper fill level ATF?

[raidermark]

I did a transmission fluid / filter change (pan only) on my 2007 Yukon XL w 43K, (4L80E). I'm trying to fill to a correct level. When I drove home this morning total 19 mi. at 45 degrees outside my transmission got to 123 degrees. The level on the dipstick was 1/4" below the bottom mark which would mean I need to add fluid. Later in the day I drove 11 mi. at 85 degrees outside the transmission got to 153 degrees. The level went 1/2" above the top line which would mean overfilled. Is this variance safe & why the big difference? Does heat expand the reading that much? (I live in Nevada, nights get cool & day gets hot).

 

[The Critic]

The fluid level will always be lower when cold.

What does the factory service manual say, is the correct procedure for checking the fluid level?

 

[Rand]

If its the normal procedure you are supposed to get it hot

then check it with the engine running.

 

[wirelessF]

ATF level is sensitive to temp changes. I check the ATF in my 4L60E when the ATF temp is at 156 degrees.

 

[Barkleymut]

You should be fine with some overfill. 1/2 inch seems to be a lot, how much did you fill it with?

 

[Falken]

I always fill the fluid to what the manual says for a drain and fill, and fill it that much exactly.

Then, the following day, without running the car and checking it in my parking spot on a dead cold engine with the engine off, I check where the level is on the transmission dipstick and take note.

On my Fit, with the factory volume, on a dead cold engine that hasn't run in the morning, the ATF fill level is EXACTLY at the MIN mark.

So now I know if I need to top up, I just check it the same way as I would engine oil. On a cold vehicle that sat overnight and hasn't moved. So if the transmission fluid level is low, I just add more until it reaches the min mark.

In the manual, it says that the level, when checking it using the procedure (op temp, engine off for less than 2 mins) the fluid should fall between the min and max mark.

I tried to check the level with the spec procedure, but in the Winter the temps are all over the place, so the level seems low some days, and other days it seems overfull.

I even pulled the dipstick once and it was aerated (overfull). So with transmission fluid, you just can't seem to go too wrong by just filling to the MIN mark on a cold engine and transmission before the car was run for the day.

So if it expands from MIN, it will fall into a nice range normally when the fluid is warmed up a bit.

I don't think that it is as super crucial as most people say. Drive the car 2 miles, park on flat and check. If it is reasonable the level I'd pay it no mind.

 

[raidermark]

The dipstick has the cross attached area. I refilled with 5 & 1/4 qt. Valvoline Dex VI. The manual says check it when warmed to 160 degrees for the most accurate reading. I'm thinking that I have it slightly overfilled.

 

[mechtech2]

ATF readings move a lot with different oil temps.
A lot.
Many dipsticks show cold/hot limits. Most show a range, not an exact level to fill to.

Also note the ambient temps affecting the ATF temps so greatly.
This applies to engine oil , as well.

 

[raidermark]

Thanks for the response. Just an added point, the manual says ideal hot level to check is 160 to 200 degrees. It doesn't get that hot unless I'm pulling my trailer. It looks like my transmission cooler is going a good job.

 

[mechtech2]

I was wondering about the lower than normal temps.
Good job.

 

[hsd]

At least you have a dipstick. Many transmissions like my 06 Jeep are now "sealed" and dont even come with one. Manual says go to the dealer even for this most basic service. I worked out my own method to check with my "custom" dipstick after sitting overnight.

 

[SteveSRT8]

Originally Posted By: mechtech2
ATF readings move a lot with different oil temps.
A lot.
Many dipsticks show cold/hot limits. Most show a range, not an exact level to fill to.

Also note the ambient temps affecting the ATF temps so greatly.
This applies to engine oil , as well.


Exactly right and one of the many reasons those dipsticks went away.

My car requires an elaborate procedure involving scan gauge readings of trans temp and a sliding fill level. It's bizarre but effective, and an infra red thermometer really makes it easy.

 

[raidermark]

I was also wondering why Lucas Transmission conditioner says you can add a qt. of their fluid without draining any out. They claim a qt. in addition to the fill level is not harmful. I would never do that but I'm sceptical of that claim of their's.

 

[SteveSRT8]

^^^That's complete garbage for some of us. Many late model slushboxes are very finicky about fluid level.

It could cause aeration and extremely erratic operation in my car as the transmission's spinning components are kept up out of the fluid normally.

Not a good idea.

Note my old Turbo 400 in a truck will simply spew the excess out of a vent tube. Wouldn't care a bit!

 

[GMorg]

So, your manual doesn't instruct you to check the ATF with a hot engine AND have the engine running AND work through DRIVE and REVERSE prior to putting the transmission in PARK? For the ATs that are familiar to me, you need the fluid hot, the TC filled, and the fluid circulating to check the ATF level properly.

 

[Charlie1935]

Originally Posted By: GMorg
So, your manual doesn't instruct you to check the ATF with a hot engine AND have the engine running AND work through DRIVE and REVERSE prior to putting the transmission in PARK? For the ATs that are familiar to me, you need the fluid hot, the TC filled, and the fluid circulating to check the ATF level properly.


Chrysler products are supposed to be checked in nuetral after running them thru all positions. Park doesn't give a true reading in them.

 

[SteveSRT8]

^^^True for many Chrysler products but not all of them!

 

[GMorg]

In any case, I was unaware of any manufacturers that recommend checking ATF with the engine off and/or the fluid cold? Falken's Fit manual includes engine off (for less than 2 minutes) procedures and Mechtech2 suggests that some ATF dipsticks have markings for "cold". Are "off" and/or "cold" recommendations common?