Oil leak question near rear main (with Pics)

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Dec 23, 2010
San Diego
1983 FJ60 with 220k miles on it.

I have only put a few hundred miles on my rig since i bought it in November of 2010. There has been several leaks and i am getting around to diagnosing the worst of the leaks. This one seems to be coming from near the interface of the trans/engine and it is definitely leaking more and more after each time i drive it. i figured it was the rear main, but after dropping the trans, the rear main looks fairly good. I will replace it anyway.

But after i removed the bell housing, i think i found the culprit, but wanted to have you guys take a peek and see if it makes sense.

And by the way, what is this plug, and what is it for? Maybe its a machine port that had to be sealed after the block was manufactured? (note that i am not talking about the Cam cover) Does any one know where to find this or what the official name is? i cant seem to find it on the spector web site or catalog.

first pic is a macro view of the rear of the engine.

rear of engine macro.jpg

This picture is a close up of where i think the oil leak is coming from. you can see oil dripping from the bottom of the plug. (note that this pic, the rear main seal is removed)

rear of engine micro.jpg

The last pic is a close up of the back side of the bell housing area that covers the plug.

bell housing.jpg
rear of engine macro.jpg
rear of engine micro.jpg
bell housing.jpg
Interesting oil leak, makes me want to check mine.

I would clean up the area and put some silicone over the plug and then re-install the bell housing for a good seal.

Definitely looks like something Toyota had to plug up from machining though. Kinda funny the plug is echoed on the bell housing with a dent, maybe to hold silicone? :D
after clean up

this is a pic after i cleaned it up a bit. anyone know what this is for?
anyone ever seen this thing leak?

close up.jpg
close up.jpg
I have been very concerned about this plug as well. I did a motor swap a couple of months ago, and I noticed thi plug had a little oil around it on the motor I was putting in. I cleaned the area and never saw oil again so I put the motor in. Well, afeter I swaped the motor, I was looking at the motor I took out and saw that the old motor actualy had an allen plug installed in that spot. The motor I took out was and 87 and the one I put in was an 84. After doing some searching, It seems as if Toyota may have realized that was a problem area, and the changed the design to use the allen plug instead of the freeze style plug. So now that I have gone through all the work of installing the new to me motor, I worry all the time about that plug. I am hoping it will not become an issue. I guess your solution would be to get that plug out and tap the hole to accept an allen plug (much like the galley repair)
Thanks for the info! Starting to shed some light on the situation. Has anyone ever done this conversion? I have done quite a bit of searching and have not come across any info. i now have clear access to the area but nervous about tapping that size hole in place. Anyone know how much clearance is behind this port?
Right Stuff

I have no idea about the clearance behind the plug or installing a threaded plug. If you keep the press in plug style in place clean it well with brake cleaner and smear a liberal coating of The Right Stuff across it. It stopped mine. 35K and counting according to the PO. Knock on wood.
That is the rear plug in the main oil gallery. It contains full engine oil pressure. They can leak. fortunately, it cannot fall out, being trapped by the BH. The plug is available from toyota. It is a Welch plug, so requires some skill for installation.

Also check the welch plug at the front end of the gallery. If it is leaking, might as well replace/reseal both.
Get a new oil gallery plug (or two) from Toyota. Pull the old plug out and clean the area up well. Install new plug with some sealer, curved side toward you. Using a large drift, smack the plug in the center with a good smack with BFH. This pushes the curved side of the plug inward expanding the plug to a tight fit. Do not hit the plug more than a couple of times. Then stake the plug all around its circumference (note how the original is staked in your photo). Let the sealer dry and start the engine up to check for leaks.
(also note that it will probably start leaking only when you get the bellhousing, clutch, transmission, transfer case and driveshafts back on and you'll get to try it all over again - ask me how I know).
You could tap the oil gallery hole and insert a threaded plug, but much cheaper and easier, and little chance of filling your main oil gallery with metal filings, to correctly install a new welch plug.
Thanks so much for the information, I will definitely plan on replacing the welch plug as opposed to tapping the hole. at $1.00 each, i will buy a few in case i mess one up. One last question, is there any more detail available for the staking process? are you using a very small punch to flatten the flange of the seal? anyone every heard of a tech write up on how to do this properly?

thanks again, what a big help!
Hey Bsquared how did your replacement of the welch plug go?

I just dropped my trans/x-fer last night. Gonna take off the bell housing today. I was having steady drops of oil fall onto my exhaust (how I found the leak).

Thanks :)
Guess they went to a screwed in plug in later year 2F's?

Yes they did. :mad:

I wish my Dad would have waited one year to get a 60!


  1. Ease of 5-speed swap
  2. This stinking oil galley plug!
Just came back from Toyota. I think I ordered the right part...

Hopefully the right part number for press in plug:


$1.26 list price. Went ahead and ordered two :cool:

PS- their parts catalogue is awesome. Too bad we can't use it
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Install results 6 months later

Hey Guys,
I am happy to report that that after several months now, no oil leaks from the back end. I did however have to replace the oil pan gasket as well.

here are a few more notes on the install of the plug.

1. make sure the concave side is facing inward. such that when its hit with a drift it will put pressure around the counterbore therefore sealing the hole.

2. in my case, i cleaned it exceptionally well and added just a light coating of silicone sealant around the outer edge of the plug.

3. a real good whack with a hammer and a flat object near the same size as the plug will seal it up.

4. next, i took the smallest punch i could find, and slowly worked my way around the entire outside of the plug giving it a slight to medium hit tat overlapped the previous hit. after about 75 hits later, it was all sealed up.

5. the pn from spector was 052-06A
Bsquared thanks for the follow up :)

Appreciate that link! I've got both the traditional expansion plug and later model threaded plug on the way from $OR. Pouring through that link, trying to find the tap size and hoping I own it. @FJ60Cam and @wngrog feel free to chime in if you know it off the top of your head ;)
Appreciate that link! I've got both the traditional expansion plug and later model threaded plug on the way from $OR. Pouring through that link, trying to find the tap size and hoping I own it. @FJ60Cam and @wngrog feel free to chime in if you know it off the top of your head ;)

I don’t, only that it is big! I let the machine shop do those. They used a tapered tap and their own plugs, where the stock plug straight threads.

If you dig really hard, I’ve seen it here on mud before but don’t remember where.

If you go the welch plug route, get it super super clean first, hammer it flat with bar stock the size of the plug (I think the factory used a press, if you look at the plug), and lock it in with JB Weld.
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