trans lubrication on startup

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Hi everyone. Ive found lots of good information on this forum for years and only just signed up.

this could be a dumb question but im having trouble finding clear information on the topic.

I'll try and keep the story short.
I just installed a bigger trans cooler on my truck. its a 09 gm with the 4l60e.
I mounted the cooler with the fittings pointed down same as the stock cooler i removed.

for the first start up i left the return line of the cooler unhooked. I had a helper start the truck. It took about 6 seconds before fluid came out of the return line.

apparently i can mount this cooler with the fittings pointed down.

my only concern is when i shut the enging off im pretty sure the fluid from the cooler would drain back into the trans.

will this be a lack of trasmission lubrication every time i start the truck?

thanks for any opinions on this.
 
You'll be fine as long as you don't slam it into gear and stomp on the gas as you start it,
then yes, there might not be enough fluid pressure to operate clutches, etc, meaning it would
rev up then slam into gear as line pressure is developed - I'm sure you're not going to do that!
 
Transmissions are NOT engines, The lube circuit that is fed from the cooler is ONLY for the geartrain that is not spinning & has zero load with the truck stationary. The Pump has to prime, Build enough pressure to stroke the Pressure Regulator Valve, Then it's on through the Converter Clutch Apply Valve where some Converter Feed is dumped/regulated by the TCC Enable Solenoid, Then has to fill the Torque Converter, Then back to the Converter Clutch Valve, Then to the Cooler, Then back to the geartrain lube.
It ONLY took 6 seconds??

 
wow! thanks for all the replies everyone that was fast.
okay it could have been a bit longer then 6 seconds maybe 10 definitely less then 15. i thought it was taking that long just to fill the new cooler my main concern was all the extra fluid it would take to fill the big cooler would delay lubrication.
i think its a lack of understanding on my part.
 
Originally Posted By: MrTruckDriver
my main concern was all the extra fluid it would take to fill the big cooler would delay lubrication.


You have nothing to be concerned about.

The oil cooler circuit doesn't affect "transmission operation". ("generally" speaking)
 
If the return line is below the level in the pan nothing will drain back as both input and output to the cooler are in the fluid level. It only drains when one side is open, like during your test. I discovered the same thing when adding a filter to the cooler lines on my 2009 F150 6R80 transmission. It only drains when a line is disconnected.
 
You'll be fine. As already mentioned don't slam it in gear the second the engine fires up. I start the engine and wait for the tach to drop to 1,000 rpms or below. That eliminates any and all concerns I had about the engine and the transmission immediately after start up.
 
With the exception of one of the three planet gears and its bearing in a planetary gear system if any , all other gears and bearings within a manual/automatic transmission are designed to be partly submerged in transmission gear oils prior to starting.
The exception above i.e planet gear, would be submerged in oil within hundreds of millisecond upon forward/reverse vehicle movement.
 
Originally Posted By: zeng
With the exception of one of the three planet gears and its bearing in a planetary gear system if any , all other gears and bearings within a manual/automatic transmission are designed to be partly submerged in transmission gear oils prior to starting.


Not really. In most automatics, the planetaries are all well above the fluid level in the pan.

It still isn't an issue, though.

Very, VERY few automatic transmissions die due to any lubrication issues.
Most fail due to excessive heat/abuse.
 
^^^True. I remember the WA580 when it came out was touted as being among the first "dry sump" designs with almost all rotating parts kept out of the fluid. Plus it had real ball and roller bearings where many slushboxes used plain ones.

And as a side note, many mornings our fleet trucks get shifted into drive nearly instantly and set out for work. No waiting is required at all
 
You're right on automatics.
I stand corrected.
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It will not drain out without pulling something in behind it. It it drains through the send line, it has to push the fluid back into the pump or somewhere else upstream. If it drains through the return, it will have to pull fluid with it.

I think once it's together, you won't see any real "draining" happening.
 
Originally Posted By: SteveSRT8
^^^True. I remember the WA580 when it came out was touted as being among the first "dry sump" designs with almost all rotating parts kept out of the fluid. Plus it had real ball and roller bearings where many slushboxes used plain ones.

And as a side note, many mornings our fleet trucks get shifted into drive nearly instantly and set out for work. No waiting is required at all


I had a jeep with that NAG1/580. it was a wonderful trans. One of the best things about that vehicle.
 
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