Thread sealant on transmission drain plug?

Hi, this is my first post - thanks in advance for your thoughts!
We just bought this used Tundra ~2 months ago: 2018 Tundra SR5 5.7L 4WD 3UR-FBE engine

I drained & filled the transmission fluid for the first time. It is leaking a bit from the transmission drain plug even though I tightened it past the torque specs. I replaced the crush washer after draining it and had the flat side facing the pan. I used genuine Toyota ATF WS fluid.

I'm leary of trying to tighten the drain plug further. I bought a new drain plug and crush washer for the next time I drain/fill.

My question to you is this: Should I use some type of non-permanent thread sealant on the drain plug threads -OR- some type of non-permanent liquid gasket? If so, do you have a recommendation?

Thanks!

 

No. Crush washer and that it.

 

I’ve never used thread sealer on the drain plug at the dealership. As already mentioned, just use a new Toyota gasket. I suspect there is some dirt between the gasket, pan or bolt. Don’t keep cranking on the plug or you will be changing the oil pan and it won’t be a good day. Remove the plug and drain into a clean container then check what the issue is.

BTW, how did you set your transmission fluid level?

 

Doesn't the flat side washer face the plug? Crimp side toward the pan?

 

I've always done it the other way around but it should still seal.

 

Flat side goes toward the plug. If it’s backward, that’s why you have a leak.

 

Considering that the gasket fits loose on the drain plug it won't make any difference which way you place it. If your thinking that the crimp side will somehow leak, it will do that regardless if it's against the pan or plug.

 

Hi from another new guy.
Suffering through the same issue here, kinda, mine leaks at level plug.
please share what you found works and your refill procedure.
Thanks

 

I replaced my transmission pan plug crush washers with oil pan plug gaskets (the blue aluminum ones from Toyota). They sealed well, and I have plenty of replacements if necessary next time I service it. Might be a good approach if the crush washers aren’t working for you.

 

Just a theory but with crimp side toward pan it digs in and doesn't move. Crimp out toward plug rotates it and bends crimp out of shape. Just changed my 2020 rear diff oil. Crimp washer was original from factory because it had black paint on edge. Both washers had paint and both had crimp toward hole.

 

Your over thinking it. I worked at the dealership level and never was there a discussion on which way the washer went and I never recalled anyone having a come back for a leak. Just use a new one.

 

Ive done 5 drain and fills. Never replaced the gasket, never used a torque wrench and never had a leak. "Tightening it past torque spec" might be your issue, hopefully the pan is okay because getting those bolts out be a pain. Never understood people using torque wrenches on drain bolts, completely unnecessary.

 

Not saying I’m right or wrong about which way the crush washer goes on but I’ll say this: on every single Toyota I’ve ever worked on that never had the trans serviced (meaning came from the factory as such) I’ve ALWAYS seen the crush washers installed on the plug from the factory with the flat side toward the plug. I mean every single one of them. I decided to keep installing them the same way and I’ve never had an issue. Just makes more sense to me is all. The plug has a smooth, flat, machined surface.

 

RuggyBuggy and boweavil,
You asked how I changed the transmission fluid. I did a drain and fill.

Specifically, I took out the transmission drain plug and let it drain, and put it back in.
I added back about a half quart more than what I took out into the fill hole
Started the Tundra and let it warm up.
I used a laser thermometer a few places on the transmission pan to wait for a temp about 100 degrees.
Took out the check/test plug and let it spill a bit.
Replaced the check/test plug and turned off the truck.
I removed my 5/8" O.D. tube going down through the engine that I used to fill it.
I replaced the fill plug.
I learned most of what I ended up doing via this youtube: https://www.youtube.com/watch?v=TH90IJSgg2M

I have since bought a Scanner with the transmission system loaded, and a live feed. The video I mention above says to wait to take the test plug out until it is in the range from 104-113 degrees.
I'm open if you have other thoughts though.
Thanks!

 

I've been using Permatex Anaerobic gasket maker on all my drain plugs. Hell, my Element still had the same crush washer on it after 10 years of oil changes when I sold it. Never had a leak.

The Tundra gets new every oil change.

 

My engine oil washer has been stuck on the oil oan since my first oil change, I couldn't get it off with my fingers and I wasnt going to chance damaging the pan trying to get it off so it's still there 8+ oil changes later, no leaks, the blue on it is starting to peel though. I have a new one if it ever decides to come off.

 

Take a flat head almost parallel to it and give it a good knock. It’ll come off. I had thought mine wouldn’t budge either during the oil changes after the dealership did them, but it really is just suctioned onto the pan.

I put a new one on every oil change now, considering how cheap it is on Amazon.

 

It's just not worth the risk to me, If I hit it the wrong way and scratch the pan then it's going to leak with or without a washer and right now it's not leaking so I'm just going to leave it alone, if it starts leaking I'll get it off.

 

If you're worried about gouging the pan, just use a brass drift, it won't damage anything.

 

Or a plastic scraper