Transmission and differential drain plugs

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AugustusFerdinand
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Transmission and differential drain plugs

Post by AugustusFerdinand »

The 24mm low profile drain plugs are known to be easily marred/stripped when attempting to remove, later model Toyotas use the same plug threads only in an internal hex (allen) plug. These are the Toyota part numbers for longer magnetic plugs for drains and shorter non-magnetic plugs for side/fill.

Low profile magnetic drain plug: 90341-18021
Low profile non-magnetic plug: 90341-18016
Steel crush washer: 12157-10010 (differential)
Aluminum crush washer: 90430-18008 (trans)
1983 Toyota Tercel SR5 - 7AGE swap in progress
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dlb
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Re: Transmission and differential drain plugs

Post by dlb »

Nice find and suggestions!
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AugustusFerdinand
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Re: Transmission and differential drain plugs

Post by AugustusFerdinand »

dlb wrote: Fri Jan 15, 2021 1:54 pm Nice find and suggestions!
Thanks!

There are two 24mm on the diff, two 24mm on the trans as drains, and either three or four 24mm on the sides of the trans as fill or other checks.

I say "three or four" on the sides of the trans because there is on on top of the trans that holds down a spring (anyone have any idea what it is for?) and I can't remember if my count of the sides included the one on top or not. The shorter non-magnetic plugs above have the same recess inside them as the 24mm that are on our trans and is present that holds part of the spring on the top of the transmission.

And there is one more 24mm on the side of the trans, but it is this weird long plug that is only threaded on the top half (nearest the head) and the bottom half is unthreaded, I don't know if it holds something in place or prevents it from turning, so I won't be replacing that one.
1983 Toyota Tercel SR5 - 7AGE swap in progress
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Petros
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Re: Transmission and differential drain plugs

Post by Petros »

not all of those are "plugs", the longer one actually holds part of the shift linkage in place, DO NOT REMOVE IT, when changing the oil.

check the FSM for which are drains, and which are filler/level check plugs. leave the rest in place.

Toyota should have used a different size plug/thread on the ones that are not for drain/refill, but the ones that are not are there for other reasons, mostly when rebuilding the trans (when it is out of the car on the bench) to facility assembly of the complex mechanical parts. of if you remove them can allow parts to get misaligned, creating a problem not easily fixed.
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AugustusFerdinand
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Re: Transmission and differential drain plugs

Post by AugustusFerdinand »

Petros wrote: Fri Jan 15, 2021 6:24 pm the longer one actually holds part of the shift linkage in place, DO NOT REMOVE IT, when changing the oil
So that's what it's for! My trans is out right now as I'm replacing all the seals, clutch, plugs, etc. while I'm doing the 7AGE swap and removed all the 24mm plugs one at a time to see which could be replaced with the internal hex plugs. Really hoping I didn't disturb something when I removed the longer one for a moment...
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Re: Transmission and differential drain plugs

Post by Petros »

AugustusFerdinand wrote: Sat Jan 16, 2021 5:37 pm Really hoping I didn't disturb something when I removed the longer one for a moment...
if you have it out of the car than getting it back in properly is no problem. there is a thread in this forum about how to fix it while it is in the car, it is not problem when it is out of the car. there is a some kind of pivot or something that the shift linkage needs to be engaged with that longer depth plug. I think with the top cover off you can actually see it and get it back in correctly, but you can also look in the hole and line up the linage part through the hole, and than thread it back in.

form member Xirdneh (aka. Robert Walker), wrote up the fix, and knows exactly what to do. I have had not ever had that problem before, I have had the transmission apart before and know that is not a drain/filler plug, so I leave it in place when I change the gear oil. and so should you.
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battmrown
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Re: Transmission and differential drain plugs

Post by battmrown »

AugustusFerdinand wrote: Fri Jan 15, 2021 12:24 pm The 24mm low profile drain plugs are known to be easily marred/stripped when attempting to remove, later model Toyotas use the same plug threads only in an internal hex (allen) plug. These are the Toyota part numbers for longer magnetic plugs for drains and shorter non-magnetic plugs for side/fill.

Low profile magnetic drain plug: 90341-18021
Low profile non-magnetic plug: 90341-18016
Steel crush washer: 12157-10010 (differential)
Aluminum crush washer: 90430-18008 (trans)
Thank you for this! I've done this mod on my '85 FJ60 and it's heaps better. Want to do it on the Terc, especially since my fill plug is mangled and I'd like to replace them all with hex heads. Do you use the magnetic for the 3 drain plugs and the non-magnetic for the fill plug?
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Re: Transmission and differential drain plugs

Post by battmrown »

battmrown wrote: Tue Feb 02, 2021 6:54 pm
AugustusFerdinand wrote: Fri Jan 15, 2021 12:24 pm The 24mm low profile drain plugs are known to be easily marred/stripped when attempting to remove, later model Toyotas use the same plug threads only in an internal hex (allen) plug. These are the Toyota part numbers for longer magnetic plugs for drains and shorter non-magnetic plugs for side/fill.

Low profile magnetic drain plug: 90341-18021
Low profile non-magnetic plug: 90341-18016
Steel crush washer: 12157-10010 (differential)
Aluminum crush washer: 90430-18008 (trans)
Thank you for this! I've done this mod on my '85 FJ60 and it's heaps better. Want to do it on the Terc, especially since my fill plug is mangled and I'd like to replace them all with hex heads. Do you use the magnetic for the 3 drain plugs and the non-magnetic for the fill plug?
It'd probably help if I read. Nevermind! Thank you!
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garyfish
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Re: Transmission and differential drain plugs

Post by garyfish »

what size allen wrench fits these internal hex plugs?
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AugustusFerdinand
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Re: Transmission and differential drain plugs

Post by AugustusFerdinand »

10mm, does the size matter?
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Re: Transmission and differential drain plugs

Post by Toyotise »

Thank you!
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