one degree from level - how much difference in ATF fill level

I've just recently purchased a 2007 T4R Sport V6 4WD with 210K miles. It's got a bit of the dreaded shudder problem, but not that bad. Shifting to 4th always stops it, and the shudder is fairly gentle when it does happen. Why it wants to stay in 5th gear when climbing a moderate incline at 35-40 mph is beyond me.

Anyway, since I have no service records, I have no idea if the ATF has ever been replaced, flushed, drained and refilled, or whatever. I figured I'd do it myself today. When I finished with 2 drain and refills of aprox 3 quarts each, and warmed the ATF up to 114 degrees (temp measured using wifi obd scanner and "Car Scanner" app) to check the fill level with that level checking drain plug (5m hex), a bit more than an entire quart of ATF came out before it slowed to a trickle. I was really surprised, and it seems to me this indicates that the transmission had a quart too much ATF in it for who knows how long before I purchased it.

My main question is: could the fact that the truck was not quite level have caused this to happen. I used a 24 inch level placed along the bottom of the frame mid truck to get it very close to level by picking the flatest section of my driveway. I'm fairly certain that at most it was sloped 1 degree towards the back (back lower than front) due to slight driveway tilt, probably more like .5 degrees (which equates to 1 inch over 10 feet).

1. If it did have one quart too much ATF in it for a long time, could this have caused damage to the transmission? It seems fine other than the slight shudder going up hills, which so many owners seem to have (even with way lower miles than mine).
2. Is it somehow possible that since the truck was not quite level that the the level checker drain plug accuracy is way off, like by an entire quart? doesn't seem possible.
3. Should the truck shift into 4th or 3rd going up a moderate incline between 35-40 mph (without me stomping on the gas a bit to force the shift), or is it normal that it stays in 5th gear if not encouraged with a stomp on the gas?

By the way, the ATF in there was black looking to the eye, but did not smell burnt. There was almost no evidence of particles (metal or otherwise) in the drain pain after i poured the oil out of it. When I put some of the ATF on a paper towel, it was a light brown - far from red, but not black and smudgy either.

A quick test drive (only a few miles) showed no change in the shudder so far I plan to do two more drain and fills next weekend then add some lubeguard shudder fix.

Thanks in advance for any answers to my questions or other insights, and thanks to all for the amazingly helpful content that's been posted here over the years.

 

Welcome, and i do not think that the amount of level you are talking about should cause that much fluid to come out. Keep the drain & fill up, see if it helps your problem.

 

Fluid temperature and the vehicle being level are required to “properly” set the temp, however, what you did is perfectly fine. Your talking about a few ml difference which is not going to have any real world effect. If they were that sensitive fluid level they would be blowing up left and right. Overfilling the trans can cause damage, especially over the long term. It’s like with an engine, if the oil is filled to high and the spinning rods/crank start dipping into the oil and basically start foaming it up which in turn prevents lubrication from
Getting where it needs to be. A transmission can do that on a much smaller scale. Usually it’s not a problem with transmissions though because of you have a shifting issue the obvious step one is checking fluid level so it typically isn’t ran overfilled long term to be able to really damage anything, this is part of the reason dipsticks have gone away.

When the fluid is filled to high parts that’s aren’t supposed to potential

 

Thanks SlvrSlug and Agent_outside. Glad to hear it, and thanks for the education