Converter drain back?

thunder550

Active member
Apr 2, 2013
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Phoenix, AZ
My truck has been sitting with no engine for about 6 weeks. I pulled the trans dipstick today and noticed it's showing over full by about 2.5 inches. Read about Allisons and drainback after sitting for extended periods, does this sound like what's going on?
 

Evan@InglewoodTrans

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Aug 5, 2010
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My truck has been sitting with no engine for about 6 weeks. I pulled the trans dipstick today and noticed it's showing over full by about 2.5 inches. Read about Allisons and drainback after sitting for extended periods, does this sound like what's going on?

Checking the fluid without the truck running doesn't tell you much.
 

thunder550

Active member
Apr 2, 2013
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Phoenix, AZ
Checking the fluid without the truck running doesn't tell you much.

I figured normally it would show a little over full but this is way over, that's why I was wondering.

So its not slanted down at all at this end? This could show higher than normal levels.

Not significantly. Engine is back in the truck as of today and I checked it after, which is when I noticed it over full.

First thing I actually noticed was the dipstick tube grommet seeping a little bit of fluid. Grommet is only about 4 months old, so I thought that was strange.
 

motoking_1990

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May 9, 2011
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Could very well be the converter draining back through the bell housing and into the pump and trans. Only way to know is start it and check again. Which will pump the fluid instantly back into the converter.
 

Mike L.

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Remember that the converter is sitting on its side and whatever fluid is above the hub will eventually drain back into the pan. Normal.
 

Chevy1925

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Oct 21, 2009
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Phoenix Az
Mike told me the same a while back. Mine sits for a week or two before I usually start it and she will need to idle for a bit to fill back before she moves


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THEFERMANATOR

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Feb 16, 2009
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I've found if I park slightly nose high, my converter drains back fairly easily. And with the engine off, your going to show way over full. With the engine off all of your apply pistons have drained down, and the fluid cavities aren't filled above the pan level without the pump running to move the fluid up to them.
 

thunder550

Active member
Apr 2, 2013
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Phoenix, AZ
That's all good news. The only other explanation was water in the trans pan from the rainstorm we got this weekend, but I could not figure out how that could have happened. That was my main concern, not worried about it now though.
 

AKlowriderZ71

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May 14, 2012
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Wyoming
I've found if I park slightly nose high, my converter drains back fairly easily. And with the engine off, your going to show way over full. With the engine off all of your apply pistons have drained down, and the fluid cavities aren't filled above the pan level without the pump running to move the fluid up to them.

Maybe that's why the factory puts the nose so low, and the ass so high on these trucks?!? To prevent converter drain back.... :roflmao: