So i drained and filled again. Got 5qt’s out of the pan, dumped in 6, and got 1.5 out again. I was on level ground and i added my 160lb Great Dane and a 40lb bag of rock salt to the passenger side to “level” it. Now I’m worried there’s not enough fluid...Our 9T65's are unique in that unlike most all transmissions that hold all of the fluid in the bottom pan, our's has a expansion tank to hold excess fluid when the trans is hot, then returns it to the sump when the fluid cools and contracts.
This operates much like the expansion tank for the engine coolant.
If you get the fluid as close as you can ( + or - 0.5 quarts) I think this expansion tank will do the rest.
It's all about fuel efficiency. Ever try to run in a swimming pool? It's hard. Same goes for all the spinny bits in the transmission. They want to keep them away from the oil as the volume increases with heat and the level rises.
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Yeah i have no idea, unless the expansion tank let go some extra fluid both timesI wouldn't sweat it.....but the math is kinda weird.
Your first post statues you drained 5 quarts out, put in 6, then lost 1.5 setting the fluid level.
This leaves 4.5 quarts.
Then in the second post, you again drained 5 quarts. Where did this extra 0.5 quarts come from?
I def let the trans get to temp, Followed the how to instructions to a T! I thought a “Flush” was bad for the transmission?Confirm you are performing the test drain plug with the trans temp at IIRC 185-203 Fahrenheit. I believe GM calls for that as that temp range triggers the TCM to release the reservoir perhaps and fill the tranny case, allowing an actual fill test. Service manual states that the reservoir is held back from release until certain parameters are met in the tranny case, one of which might be the temp range.
Also confirm you are performing the test with the engine running when you pull the plug. These are just to check nothing was missed or skipped by you.
I performed the drain and fill (but not the flush yet) on my 2018 HC last month, which was getting the shudder in low gears and lower end of speeds. My tranny temps were reaching 190-200 regularly after 30-45mins of driving and stop and go traffic. At these temps, the shuddering was always present (not to mention, when on first start and pull away from park, it would always slip at about 2-3 or 3-4 gear like clockwork on initial drive).
I drained only 5 quarts from my tranny, filled with six, ran the engine till that temp range (my HC still has the tranny temp on the dash display) and pulled the drain plug. I was only able to drain about 1/3 of a quart out. Garage is perfectly level (even checked with an actual level, as I change my oil as well for years here). Old tranny fluid was dark cherry/brown, but more brown than cherry. I have pics on my other phone, unfortunately.
Drove the car about 100 miles so far, not enough for me to do a flush yet (waiting to hit around 500 miles), so far, no shuddering, no gear slipping on first pull away and the tranny temp has not gone over even 175 so far and that's with ambient temps in ~95 degrees and stop n go traffic, same conditions that previously caused it to hit 190+.
So perhaps mine was under filled? Won't know really until I do the flush and see what I get on the drain/fill/test.
I used this one here Valvoline DEXRON VI/MERCON LV (ATF) Full SyntheticWhich fluid did you use for the service ?
Indeed. From the same screenshot above, Amazon.ca has a Case at $77.95 Cdn. That works-out to 12.99 per quart. Half the price of a Single quart. That is a bit better.You should try searching by the case, it was the same here in the US, expensive per quart, cheaper by the case.
220 seems high on an 80 degree day. I just ran some serious highway mountains on a 95 degree day at 75 mph and maxed out at 208 degF. Now I do have the tow package but even without it I would be a little uncomfortable with 220 for any amount of time. Just my opinion.Gotcha. Sounds like I can lower my DEFCON level a bit￼. Was probably 80° out and was going like 80mph for an hour or so...
Hottest it got was 220°. That sound ok? (Thanks for your write ups!)
You've got me thinking that the tranny wasn't hot enough when I checked the fluid level; I'll revisit and post results. Hey, is there a transmission temp idiot light associated with this?#1 cause of overheating? Transmission is over full.
Checking the level is easy.......
On the freeway without towing anything, the T/C is locked up most all the time, which should keep the temps down.