4l60e pan leak? or cooler line?

[apollo18]

Hey guys my truck has the 4l60e and about 10 days ago I dropped the pan, installed a new gm filter and gasket and then reinstalled the pan. Torqued it to 11 foot lbs with a torque wrench. I then removed the cooler line and did the cooler liner exchanged. I filled it to cold and then drove around for 30 mins and added again to get it to the “hot” section. The next day I hit the highway and drove 600km. Everything went fine, 2 days later I noticed the transmission RPM were surging when I would shift from reverse to park, park to drive etc so I thought it was due to the cold weather or something. I hit the road again and after 100km I pulled over and filled gas and checked the transmission fluid and it was in the cold region again, weirdly so I added again to get it into the hot area and continued on with my day. The surges were due to the low fluid it seemed so once i filled up it was all good. This whole last week I didn’t drive much so I couldn’t get it hot enough to check but i didn’t notice any surging/rpm spikes so I assumed everything was good! Yesterday I checked the fluid again when it was hot, and it was back down to the cold region again. So I added again for the 2nd time. I heard that sometimes air gets in the system when I remove cooler line and do the exchange but I doubt it could be that much. I assume I have a small leak or something? It seems to only like the amount between cold and hot on the dip stick which is like 250-400mL maximum imo. What do you guys think it is? I assume pan needs to be retorqued again? Or maybe the cooler line is leaking but I checked quickly and didn’t notice anything. Anything else I should look at?

 

 

Thanks!

[Formulabruce]

The original "Gasket" is a metal filled rubber 1 piece "SEAL" . The replacements are thin and folded when you buy them.

 I Always use the original "SEAL" to prevent any pan leakage. I have seen many replacement gaskets leak on these after the great original

"Seal" was tossed  for a folded up gasket. Even with the original type seal, a small amount of re- tighten may be needed.

Edited February 25, 2020 by Formulabruce

[apollo18]

Ahh ok! I had a mechanic do a pan drop a couple years ago and it looked like the exact same gasket was still on it. A paper one. Maybe I just tightened it too much or do you think the bolts just got a little losse

[txab]

If you torqued to 11 ft lbs, then you're plenty tight, as the specs I saw show 11Nm or 97 inch lbs., which is basically 8 ft lbs

 

If you're losing fluid, it will be easy to see all around the pan or the cooler line connector

[apollo18]

it has 240,000 km on it, when i changed the fluid the old fluid was still red and smelled fine. i did a pan drop 5-6 years ago so it kept the fluid fresh!
i heard when you do the cooler excahnge method which is what i did, air can get stuck in the system which causes the level to lower until all the air is out, but ive added 1/4 quart about 5 times over the past 2 weeks but i cant find any leaks. i parked the truck in the garage while i did oil change and some other work and nothing, bot even a drip. i checked the cooler line area and it was clean too..

can it honestly be that much air?

what i also noticed is the level never dips below the "cold" mark on the dipstick, i always check when the tranny is hot but when it does lower its always showing on the dipstick.

thanks!