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No, it is not sudden. It has been worn down with the 160k mileage but the tc was still concentric to the seal UNTIL it was removed and reinstalled. During re-installation, since the bushing is worn, nothing to hold the tc concentric to the seal when the 6 tc bolts were tightened....
...
And I made sure the 2 dowel pins were between the engine and the tranny.
And I used OEM seal.... and I examined everything. Torque converter neck, no scratch on the metal where seal sits, pressure tested the TC, made sure the seal sits perfectly flush.... carefully push in the TC into the tranny shaft....
No leak after installing. No leak during and after 30 mins of idling. Took it out for a freeway ride.... came back and checked under and I got this:
STILL LEAKING!!!.... and only when engine + tranny running at high speed.
This is the worst set back I have had for 30 years of fixing cars. I am literally crying inside now. This is for two mini coopers, both 2010, one is R56, another is R57. They have N14 engines and same tranny.
What could that be???
1. I use valvoline maxlife ATF. It is thinner than the OEM Fluid and hence easier to leak out?
2. The bushing inside the front pump is worn on both trannys, allowing more ATF to pass thru and when running at high speed with high pressure, some leaks out? I don't recall / believe they were leaking prior to taking the engine off.
3. With the engine separated, somehow the torque converter is not bolted on to the flexplate perfectly inline anymore hence the neck is not concentric to the seal, allowing fluid to leak out when running at high speed?
Or 2 and 3? Separating engine and tranny disturbed the "concentric" when the bushing is worn?
Remember the tranny held up 5 psi of pressure overnight. Seal is sealing (when stationary) unless the TC neck is not concentric to it and is spinning really fast (like 4k engine rpm...)
Is that nub on TC a tight fit, by design, into the center hole of the flexplate, thus, forcing the TC to be concentric to the flexplate?
Is there a star torque pattern to tighten the 6 bolts on TC?
If above does not explain the problem, I have no idea... Please help / comment.
The tech sheet for the fluid your using says it is compatible with JWS 3309, so the problem is probably not fluid related. Did you ever find out if the seals are PTFE seals?
I don't think it is a PTFE seal. Here is the official workshop manual from newtis.info:
It is just pushed in with the special tool 24 4 250 that I don't have and I don't plan to buy. Yes, I still don't know if it should be a flush install or not.
No way it could be a PTFE because u have to install the TC and twist and turn to get it into the grooves, don't u think.
I can't think of any other reason besides the pump bushing being worn, making reinstallation of TC off-concentric to the seal, and I can't believe I have such bad luck with 2 transmissions doing the same. Am I the only one?
Replacing the seal is other can of worm as I need to take apart the tranny.
It is an Aisin 6F21WA which seems to be under TF-60SN:
And same, or at least similar to, VW 09G tranny. There should be a lot of youtube videos for it.
Last edited by Derek Chung; 10-13-2022 at 01:58 PM.
I can't think of any other reason besides the pump bushing being worn and I can't believe I have such bad luck with 2 transmissions doing the same. Am I the only one?
Nope you're not bro...happened to me and the dealer.
Right, Lex2008, thanks for being here supporting me.
My next move is to get another used 6F21WA and figure out how to change the pump bushing and install it on to one of my 2 coopers. If that solves the problem, I will replace bushing of the tranny I take out and install on to the 2nd cooper.
Looking forward to seeing more comments. I really would like to hear your story.
Here, this is a good video to explain my situation:
I'm pretty sure my dowls were in as well. I'd have to look at my old pics but I was pretty careful about using the dowels where needed. Mini uses those things everywhere. Japanese card Ive worked on don't other than trans.
Why dont you just install a used transmission from LKQ? Thats what I had to do. Those trannys are old anyway.
Thats part of the reason I didn't keep trying to fix my leak...my trans had 145k miles. It still shifted fine but it had never had its oil flushed by previous owner. Because of the mileage and because I was putting in a new motor I went ahead and installed a used trans with a 1 year warranty.
But trust me I understand wanting to fic what you have.
Who knows if LKQ tranny, or all mini aisin trannys have the same weakness. Warranty is one thing. The labor to take things apart is another. I am actually good at it. Just 2 hrs I could pull the engine tranny out.
I think to change out bushing, the pump needs to come out. Need the $5 bushing and a $18 gasket. I will read up more before pulling trigger.
Bought the brass bushing and metal gasket. Order being shipped to me.
Found a tranny at junk yard.....
Plan to take apart the front part of the tranny to get access to the front pump to change out the bushing next weekend.
90% chance the TC neck is no longer concentric to the seal after it was removed and reinstalled because the bushing has been used for 150k. The seal seals ok when stationary or low engine rpm (because the seal rubber and the inner spring) but at high rpm, could not keep up. Getting everything concentric should make the whole car smoother too I hope.
Or I pushed out the inner spring (behind the seal) out when I pushed in the TC, four times.
Or flush mounting the seal is not right. I don't know because I don't have the special tool.
Or I lost the 2 dowel pins I did not know and the tranny is not concentric to the engine (but I am 99% I saw the pins.)
I asked some professionals on youtube too:
I will report back when I have more info.
Does it mean every time someone separate mini cooper engine and aisin tranny, if mileage is high, the front pump bushing should better be replaced, otherwise tc seal might leak? How come I don't see people, except u and me, here talking about that.
Derek this video is super cool. First thing....i was told by my local transmission shop that almost no one rebuilds these and i was quoted $5k to rebuild one. Absurd. So i was shocked to see this awesome dude taking that thing apart and slinging parts like he'd done this a thousand times! Who is this superman?
I love how these transmission guys are swimming in oil all day. Cracks me up. It's like an eternal oil change.
A million parts to consider when you do this. I guess if you're real careful it's doable. The problem is if you mess any of it up you gotta take the darn trans out again ... Nightmare.
Does it mean every time someone separate mini cooper engine and aisin tranny, if mileage is high, the front pump bushing should better be replaced, otherwise tc seal might leak? How come I don't see people, except u and me, here talking about that.
1. Most mechanics wouldn't touch that seal cause they scared or know better
2. The transmission (Japanese) last longer than the motor (French) in most cases anyway
3. Most people on this forum want to talk about the color of their side mirror covers not actual mechanical work.
1. There is same (little) amount of play on both TC necks to existing bushing when TC is installed and wiggled left and right.
2. No wear on the neck of both TCs.
3. When new bushing is test-fit on the neck, it has small play and enough that I don't think it will stop ATF from passing thru. It is there to keep the TC straight.
4. We pressure tested the TCs. No leak.
5. TC seal looks good. And both OEM and aftermarket from Oreily look the same. (OReilly one is of FKM material)
We could not convince ourselves to take apart the tranny to replace the bushing. We also kept using the old tranny as we don't see the new one any better.
I know we did not torque the flexplate (to crankshaft) and six TC bolts to specs so we took the flexplate off, clean up any surface rust, and reinstalled everything according to newtis.info.
Today I will refill the ATF and drive it around to see if it will still leak.
If it does, I GIVE UP.
10-13-2022, 07:18 AM
