Filling a 4t65e transmission. Ran into a snag

[sero5454]

I recently drained and changed the filter on the 4t65e in my Buick lacrosse. I was meticulous about measuring the exact amount that came out (8.1 quarts exactly) and that was what I was going to put back in of course but when I was refilling it I accidently spilled some and lost track of how much I had actually put back in. I'm thinking of draining it all out again (the same amount that drained the first time around should come out this time, yes?) and then refilling again with 8.1 quarts this time avoiding spilling. I am also planning on adding a transmission cooler to the system (my car has about huge amount of space between the grill and the condenser which I figure is a good spot to put in an 18 inch tranny cooler cause why not). The cooler is supposed to hold 1.5 quart or so which I am thinking of just filling the cooler separately before I put the hoses on it to save on the guesswork. The old fluid that came out was actually fairly clean (car has 80k miles on it) so I think I'm doing pretty good on that front. The magnet barely even had any gunk on it, just a thin layer of black stuff, and no ferrous gunk any where else in the bottom of the tranny (whew!) . The car was seemingly having torque converter issues at one point but like a lot of the gm 3.8s it turns out it was just a case of bad motor mounts masquerading as a torque converter issue.

 

[Oro_O]

You still have to manually check the fluid level, that is not optional.

The excess flows out when you do. Brush up on that proceedure. Don’t “guesstimate” your ATF fill volume.

 

[atikovi]

I was meticulous about measuring the exact amount that came out (8.1 quarts exactly) and that was what I was going to put back in of course but when I was refilling it

What does that have to do with the correct level? Fluid may have leaked out. Enough fluid may not have been put in the last time it was changed. Or too much put back in. What's so hard about checking the level that you can't fill it close, then keep adding a 1/4 quart at a time until it's right?

 

[JustN89]

This trans has an old school dipstick. Put back what you got out, but go through the process of measuring the fluid. It's straightforward:

1) Run trans ato operating temperature. Idle about 20 minutes or drive for about 15 minutes, but you're ideally looking for between 180*-200*.
2) With engine ON, shift to Park.
3) On level ground, pull transmission dipstick. Read both sides, but the lower side is the correct reading.
4) Fluid should be in hashed area of dipstick. If low, add fluid. If above, remove fluid. For removing fluid, using a cheap fluid extractor from Amazon, run it down the dipstick tube and begin to remove fluid until level is correct.

Easy peasy.