Transmission Drain/Fill gasket orientation

Dealer-provided metal gaskets for drain and fill plugs; requesting info on proper orientation.
See photo; the gasket has a smaller OD on one mating surface vs the other mating surface.
Narrow side next to the plug, wider & flatter side to the transmission?
Thanks.
Dealer-provided metal gaskets for drain and fill plugs; requesting info on proper orientation.
See photo; the gasket has a smaller OD on one mating surface vs the other mating surface.
Narrow side next to the plug, wider & flatter side to the transmission?

 

Pretty sure it doesn't really matter because it gets crushed anyways, but I usually do what you suggest with the larger OD toward the pan.

 

This. The gasket gets crushed when you tighten the bolt.

 

Good to know it doesn’t matter.
Taking off the factory-installed plug shows they install the flat surface against the plug, the other (narrower) surface next to the pan.

PS I took out 4.5 qts, then installed 4.5 qts, cleaned it up and went to the dipstick to ensure it was at the correct level……

 

Dipstick???

 

you got it.

 

https://youtu.be/MsBeEVUdo98?si=m8yFnYbYwkBzthDB

 

He also has an 03 it looks like. Maybe the 03 has on. If his 20 has one then it's a unicorn that farts rainbows.

As for the washer, they need replacing?

 

I put the smooth side facing the bolt because this is how both came off from the factory. The pic on 1st post would gave the bolt come through the bottom and the washer would go against the pan just like the picture. Top of picture against the pan. So I say opposite as what OP posted.

Crush washers should be replaced each time. The oring on the fill plug is most likely alright if it looks good.

 

Specifically, I'm liking the flat side against the bolt portion, since that's how mine came out, too. The o-ring, I'm a big believer in doing you, but if you happen to care, you're already this far for an extra $1.25 for an o-ring. Again, do you.

 

I did mine at 60k miles and the fluid was dark and kina foul smelling. So I did it again a few hundred miles later. Now it's bright red.

 

If I remember correctly, the flat side goes to the bolt head. Round (crush) side to the pan.

In all honesty, it’ll likely work either way though. Put it on and torque till the bolt spins freely.

 

I’m almost certain I put the crush washer backwards from the original orientation of the old one on mine and zero leaks. I doubt it matters.

 

One thing to be careful of here.. at least I got burned by it once and it was no fun. If you're going to do the full procedure, monitoring temps and waiting for the trickle before you hit the upper edge of the temperature range, I'd suggest re-using the previous washer for the duration of that test. Have the new uncrushed washer under the truck with you and install it on the drain bolt while you're waiting for the trickle.

First time I did the level check process, I had a new crush washer on the drain bolt while the truck was coming up to temperature. When I pulled the drain plug to start the level check, the bolt came out, but the new drain plug stuck to the pan. For a second. And then it got ejected a few seconds later into the drain pan. Since then I reuse the old one for the test and while I'm waiting for the damn trickle I kill some time by putting a new washer on the drain plug.

My local dealer throws drain plugs my way when I buy oil filters (and their prices are really fair). Last time I was doing the trans fluid I asked him if he had the transmission drain plug washer in stock and he just tossed that in the bag too.

 

^^^Good advice.