ive wondered this before. It’s a pretty heavy cast aluminum piece and it fills a part large gap between engine and trans

 

FYI for anyone reading in the future...this is WAY not true. Like not at all true

 

for anyone reading this in the future, call a reputable transmission shop and ask them how much a thin unsupported 4l80 housing flexes with no cover, or trust the random guy on the internet saying “way not true”..
combinations will always differ, but what i said is very much true, been thru it and why i always ask..

 

Or you could look at the 100's of 4l80e's out there making 800+ hp with no cover and doing fine

Or all of the 4l80e's gm put out there with nothing more than a stamped steel dust cover. Any SBC or BBC based engine that didn't have the bolt holes in the oil pan got that stamped cover and they're all doing fine.
1 ton applications, no problem.

The cast aluminum cover was used to catch the 2 extra bolt holes in the oil pan so it was attached to the LS in the same manner the 60e was. The 4l80e case is not weak and won't crack if you don't use that cast aluminum cover.

 

Time has told us that they aren’t needed and generally aren’t ran. Jakes Performance website suggest using the cover for off-road to keep trail obstacles from tearing up your converter and flexplate and that not having one on could benefit converter cooling on the flip side. All about how you use your rig.

 

Correct. Application specific.
But not having the cover will NOT result in pump damage. That's just wrong information