Snake Slayer

I was able to use the search function and came across the following:
Service Information. My question for those of you that have done this is when checking the fluid using the directions below, is the fluid supposed to drip or flow?


2008 Chevrolet Corvette | Corvette (VIN Y) Service Manual | Transmission/Transaxle | Automatic Transmission - 6L50/6L80/6L90 | Repair Instructions - On Vehicle | Document ID: 1593625
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Transmission Fluid Check
This procedure checks both the transmission fluid level, as well as the condition of the fluid itself. Since the transmission on this vehicle is not equipped with a fill tube and dipstick, a tube in the bottom pan is used to set the fluid level.

Notice: The transmission fluid level must be checked when the transmission fluid temperature (TFT) is between 30-50°C (86-122°F). If the TFT is not within this range, operate the vehicle or allow the fluid to cool as required. Setting the fluid level with a TFT outside this range will result in either an under or over-filled transmission. TFT>50°C=under-filled, TFT<30°C=over-filled. An under-filled transmission will cause premature component wear or damage. An over-filled transmission will cause fluid to discharge out the vent tube, fluid foaming, or pump cavitation.

Observe the TFT using the driver information center (DIC) or a scan tool.
Start and idle the engine.
Depress the brake pedal and move the shift lever through each gear range. Pause for at least 3 seconds in each range. Move the shift lever back to PARK. Ensure the engine RPM is low (500-800 RPM).
Allow the engine to idle for at least 1 minute.
Raise the vehicle on a hoist. The vehicle must be level, with the engine running and the shift lever in the PARK range.



Notice: THE ENGINE MUST BE RUNNING when the trans oil level check plug is removed or excessive fluid loss will occur, resulting in an under-filled condition. An under-filled transmission will cause premature component wear or damage.

Important: Continue to monitor the TFT. If the TFT is not within the specified values, reinstall the trans oil level check plug and repeat the previous steps.

Remove the trans oil level check plug (1) from the transmission fluid pan. Allow any fluid (2) to drain.
• If the fluid is flowing as a steady stream, wait until the fluid begins to drip.

• If no fluid comes out, add fluid until fluid drips out. Refer to Transmission Fluid Fill Procedure .

Inspect the fluid color. The fluid should be red or dark brown.
• If the fluid color is very dark or black and has a burnt odor, inspect the fluid and inside of the bottom pan for excessive metal particles or other debris. A small amount of "friction" material in the bottom pan is a "normal" condition. If large pieces and/or metal particles are noted in the fluid or bottom pan, flush the oil cooler and cooler lines and overhaul the transmission. If there are no signs of transmission internal damage noted, replace the fluid filter assembly, repair the oil cooler, and flush the cooler lines.

• Fluid that is cloudy or milky or appears to be contaminated with water indicates engine coolant or water contamination. Refer to Engine Coolant/Water in Transmission .

Notice: Refer to Fastener Notice in the Preface section.

Replace the trans oil level check plug and tighten to 25 N·m (18 lb ft).
Inspect for external leaks. Refer to Fluid Leak Diagnosis .
Reset the oil life monitor only if the fluid was changed.
© 2009 General Motors Corporation. All rights reserved.

Gearhead Jim

Any overfill is a self correcting problem. If it flows out, a few seconds later it will be just a drip.

The basic concept is that the fluid should be level with the hole when warmed up and engine running. Any excess will flow/drip/sneak out, wait til it's finished and replace the plug.

cclive

Remember though, that 86-122 degrees is not warmed up. If you go out and drive the car till it is warmed up, then it will take quite a while to cool off to this range. I don't have an auto, but I would expect that normal operating temp of the trans is somewhere around 200 degrees.

86 to 122 degrees could me the 'first thing in the morning' temp of a car in a garage in Texas in the summer, in other words, the "cold" temp.

Gearhead Jim

My A6 temp starts out at whatever the temp is in my garage. After a few miles of driving it will be up to about 145'F, seldom gets above 165'F.
So your numbers are too high, but your point is correct- I've had to shut it down for a few minutes to let the tranny cool off to proper temp for the check. Thanks for mentioning.

Snake Slayer

So you are basically saying that if the temp are correct and with the engine running once I remove the lower pan bolt fluid should only flow if it is overfilled? and If fluid begins to flow I should let it flow until the streams become a drip ?

Gearhead Jim

Yes.
But let's get verification from some other membgers here.

danl72

Thanks for the info.

cclive

Wouldn't it be the UPPER pan bolt that sets the level? the lower one would be the drain???

Easy Rhino

The so-called "warmed up" temperature is NOT entirely to account for the expansion of the fluid for temperature. Tranny fluid does have a small expansion coefficient of temperature, but not that much, and certainly not enough to make a real difference in fluid level all by itself.

The point of having the tranny warmed up, besides expansion, is to be assured that the fluid is completely distributed through the transmission, which is critical to fluid level.

It is just as important that it is level and running when checked.

FWIW, my tranny runs around 155F typically, although it does on occassion get hotter when sitting in traffic.

Gearhead Jim

My 2006 service manual has a cutaway drawing that shows removing the bolt/plug on the bottom of the pan to check fluid level. There is a standpipe inside, extending up from there, so you don't drain all the fluid.

cclive

Interesting! Thanks for the explanation. That standpipe would give a very accurate level in the pan...