Getting the correct transmission fluid level

[92luminaCoupe]

I have a 1992 Chevy Lumina Euro Coupe 3.1mpfi 3+OD (4t60??) I would like to know where the proper level is on the dipstick. The instructions in the owners manual explain the proper check/add procedure, but fails to explain what the 3 holes mean, the line between the upper holes, or the proper level on the dipstick. Please if someone can explain/dumb it down for me, I would appreciate it. 

Edited November 1, 2023 by 92luminaCoupe
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[Go4DaMo]

The holes are for easier visibility of the fluid.  Wow...I miss those dipsticks!  My Getrag 284 dipstick is, at least, wide.  But, it's more difficult to read.  If all 3 holes have fluid, you're great!  If 2, youre' good!  If 1, add some fluid

[92luminaCoupe]

Appreciate the information. This is how my fluid appeared after checking according to the owners manual (transmission warm, running, and shifted thru every gear). The green line is where my fluid was, the green dots were filled holes. Wasn't sure if I should add until the third is filled or if that is too high. I've heard some w-body guys say to overfill a bit. Either way if anyone knows let me know. It's an older car and I just want to take care of it. 

[Go4DaMo]

When checking, ensure you're parked on level ground.  To ensure accuracy, I've always pulled the dipstick, wiped, then stuck it back in ALMOST to where it will seal back on, then pulled it back out and checked the level on the dipstick.  The suction of pulling it out the first time may jump the fluid level (at least on engine oil, it does).

That said, add to where all holes are filled.

I'm not sure about purposefully over-filling it. Generally, when something is overfilled, it will find its way out somewhere.  As I recall, my 4T60 took over 20 quarts to fill, so it would take many extra quarts for it to be "over-filled."  It's not as precise as a 6-quart crankcase.

If it's TOO low, it will slip and not want to hill-climb.  But, that should be like 10 quarts low to notice.

[Schurkey]

Overfull can lead to aeration of the fluid when it gets beaten into a froth by the rotating parts of the trans.

Underfull can lead to aeration if the fluid pick-up gets uncovered by acceleration or cornering.

You're in the middle of the acceptable range.  Shut the hood, walk away.  The fluid level is fine.

 

 

Depending on condition/age/mileage, you might want to drop the pan, change the filter, flush the fluid.