4L80E fluid quantity.

Pinger

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According to the GM manual a 4L80 requires 7.3 litres of fluid for just a pan change and and 12.8 litres after overhaul.

I removed 5l from my pan, filled it with 7.3l, pumped a further 6.5l out of it to flush the TC and then added 5l and on level ground the dipstick has oil way beyond the marks - right up at the second (from bottom) kink in the stick. Fluid still cold and cooler empty (as thermostat now fitted). No leaks or oil loss through the breather (if there is one). It drives fine. Ran it through all the gears while stationary as recommended and drove in D all the way to 4thOD.

So, 11.5l removed, 12.3l added and the stick is showing it to be overfilled.
I didn't get the chance to check the stick on level ground before I started - only on a steepish sloping driveway, truck pointing nose down. It was u to the first kink. After draining the 5l and adding 7.3l (before TC flushing) it was up to the space between ENGINE and IDLING on the stick.
In the same orientation the current level is up to the start of the script stamped into the stick (but to the second kink on level ground).

I have in it 0.5l more than before (it ran OK before) and have underfilled it relative to GM's figures. GM figures ie, 7.3l into the pan.

Were there different size pans? Confused that mine only had 5l in it but adding the recommended 7.3l is looking like a massive overfill on the stick despite me still holding back 1.5l (6.5l removed from TC, only 5l added to replace that). The cooler will still be empty (but it doesn't hold that much).

Should I remove some or run as is (as I haven't achieved GM's recommended fill quantity so underfilled from that perspective)?
 

Pinger

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If it is overfilled (stick says it is) will it be harmed?
All in all it has 0.8l more than's been in it all year. But 1.5l less than GM reckon should be in there.
(The cooler - when the 'stat opens - will absorb some of the excess).
 

Pinger

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I'm not sure how much over it would take, but too much fluid can lead to foaming I believe, which can cause over heating. I'd just watch your temps.

No temp gauge. Only feeling if the thermostat has opened.
0.8l more than all year when the cooler barely saw heat - hence the thermostat now fitted.



I run mine on the low side of warm full. I think that's better than a little over full.

But under filled relative to 7.3l GM specify for the pan.

Does this look lie the standard pan - or do I have a smaller capacity one?
(When I check with the stick, it is with the stick fully inserted (as if refitting it for keeps - as per Haynes)).
 

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Does this look lie the standard pan - or do I have a smaller capacity one?


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Supercharged111

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Does this look lie the standard pan - or do I have a smaller capacity one?


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Looks like the pan on my 1500. I'd have to run out to the dually to verify its pan, but I think it's the same. The early 4L80s I think had a different pan.
 

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Looks like the pan on my 1500. I'd have to run out to the dually to verify its pan, but I think it's the same. The early 4L80s I think had a different pan.

Mine - in the photos - is from a 1999 C2500 Suburban. Stuateng confirmed the gasket as original GM and that and the 40,000 mileage leads me to believe that this is the first time the pan has been removed. The truck came with a filter and gasket (but for a 4L60E) so fluid change was planned (before PO's other plans changed and they sold the truck).

The only thing I can add is that when I drained from above with a vacuum tool I marked (with a tywrap) the length of the dipstick and put the suction pipe down the same length. With the pan removed I could see it protruding downwards 1/4'' out of the dipstick tube. During draining when I pushed the suction pipe down a smidge further it was in contact with the pan (a raised portion in the corner just visible in the first photo I think) enough to block it.

Just can't get my head around filling it as per official GM manual can create an overfill.
 
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