Stripped transmission drain plug

The drain plug is not tightening anywhere near torque spec. I hate the local mechanics so much. They cause one thing after another. I found it was bad when I emptied it and reinstalled the pan earlier this year and carefully turned it to the tightest orientation I could. Today I saw it was seeping a bit. I backed the bolt out a little, tried torquing again to see where it was and make sure I really did have it in all the way, and it kept turning. It's more than finger tight and is actually not seeping at all, bone dry, after a good test drive and checking it a few hours later. So I probably have some time. A little worrisome.

The pan is discontinued. I could check with some dealers that still list it but based on past experience I assume it's unavailable everywhere. No aftermarket part. Here's the parts list.

https://parts.toyota.com/a/Toyota_1...ANSMISSION-CASE--OIL-PAN-ATM/675460-3503.html

First idea - Clean and spackle the plug area generously with RTV sealant which I have handy, or something else to make that bolt not want to vibrate loose? I wish I could age it somehow to make it stick, like old bolts have to be popped free.

Otherwise, what is the bolt size? I think I'll need to know that no matter what else I do. All I know is it's a 14mm head and the bolt part number is 9011906513 which from pics includes the washer.

From what I've read it's a bad idea to heli-coil a drain plug What about a slightly oversized self-tapping plug that I've read about? I assume I'll need to drop the pan to avoid shavings. I only put 4,000 miles on this fluid and I'd rather not drop the pan again now unless it's the only option.

 

Timesert

https://www.timesert.com/html/drainplug.html

 

Do you know what size? Their "drain plug application chart" doesn't exist and is a link to autozone who has only oil drain plugs listed for my truck, not AT drain plugs.

 

Just get a new or used pan!!

In any case dropping the pan is the best way to fix things correct.

I have repaired many Transmission pans they strip quite easy . There are only a few threads.

In the old days you dropped the pan to change fluid.

I weld a thicker square piece with a weld nut welded on never had a failure that I ever heard.

I would need to double check what thread I used.

 

Well, you need a new drain plug anyway right? Just order a new one from the dealer, and when it arrives, use a thread checker to figure out what size it is Then order one of those insert kits. They look like a good solution—sort of a solid Helicoil.

The internet is great, and someone on here can probably confirm what size the drain plug is, but sometimes ya just gotta jump in and go for it.

 

Have you tried tapping it? Should be a 7 or 8 mm.

Tap the threads and buy a new drain plug and washer. Use some loctite if you want reassurance it won't back out.

 

My understanding is tapping to the normal size is more for fixing a damaged thread that is causing a bolt to stick on partway. Wouldn't it just make it worse in this situation where the bolt is too loose?

This pan is not available new or aftermarket anywhere, and nobody is parting them out. Pretty much everything on my Tacoma was only used for a couple years for this specific 2wd 3.4L model and nothing else.

I was going to order a replacement plug, but what they call the "transmission drain plug" they list as 19 qty, meaning 19 are used on this truck. That makes it look like it's one of the pan mounting bolts, and from a pic elsewhere that's exactly what it looks like. The only other possibility is the "front" and "rear" transmission drain plugs which appear to be for the differentials.
https://parts.toyota.com/a/Toyota_1...ANSMISSION-CASE--OIL-PAN-ATM/675460-3503.html

The oil drain plug is a 14mm head. Would it be the exact same plug? I think the transmission plug has an aluminum crush washer, which is not listed on the above page.

The time-serts part they say I need is $127, which seems insane, and I'm not even sure they're right about the size because I've found that stores like this are always wrong about everything my truck.

 

Parts catalogs can be a challenge. Especially so if your truck is not a common model.

Have you tried using a parts house that goes by your vin#.

https://partsouq.com/

https://www.toyodiy.com/

 

toyodiy and parsouq were helpful at least to confirm what toyota says, and I was reading the diagram wrong. It's these, also referred to as the "front" drain plug which I was thinking was for a front differential.

35106A PLUG SUB-ASSY, DRAIN (ATM)
90341-10006 1 $3.16
35106B GASKET, DRAIN PLUG (ATM)

$11 35178-30010

35178-30010 1 $2.49

I was about to give up and give it to a local shop. Unfortunately they didn't have any way to fix it beyond epoxying a new plug in. I guess I'll do that and never change the fluid again.

For my A340E I found reference that it's 1.6 quarts fill, but 7.2 quarts capacity. I think I remember having to put in way more than 1.6 quarts when I did the pan last time, and it might have been 7.2. That seems like a huge difference because there's almost no difference with just the little bit of fluid left in the pan when draining. So I don't know how to approach this when refilling, because I'm not going to have a functional drain plug if I put too much in, and I have to run the engine warm to get an accurate reading.

 

Measure how much you empty and put exact amount back in. Mine took 3.5 qts. AT Type IV

 

Dextron isn't good? I can't get T-IV fluid in the next couple days.

 

Dextron II is fine if your working on the 1996 Tacoma!

 

Is welding a nut to the bottom of the pan an option?
Sure it might require pan removal, but what are the other choices?

 

Dextron II doesn't exist anymore does it? The only thing I can get by Wednesday is Dextron VI. Dextron III is on Amazon but they can't get it to me quick, and I need it yesterday.

 

No, I'm not a welder. The other choice I thought was epoxying the bolt in? Will that not work?

 

If you never plan to remove the bolt.
Then I guess?

But I would bet there a guy at the local exhaust shop that would weld a nut on the pan for you.

 

I looked up exhaust shops and there's nothing near me but the mechanics I already know, and they always have a 2 week appointment lead time. You can't just walk into a place around here and expect service, and they're all busy and nobody is interested in doing anything they can't rip someone off for $500 on. I'm going to JB Weld it.

 

You don’t have anything to loose by trying
Go for it

 

So is Dextron VI really going to ruin it? That's what I put in this year. Whatever I put in this time is going to be in there forever, and I really need to put in whatever fluid I can get 8 quarts of the quickest.

 

The problem I’ve run into with self tapping drain plugs is when you take them out sometimes they don’t want to go back in and torque down. I might try something like this. Maybe use some high strength heat resistant loctite. Maybe some red 272. It wouldn’t be permanent that way but should stay in there and you can remove the smaller plug to drain the fluid if you needed to for some reason.