Metal ball on the tranny drain plug magnet. What gives?

[AxisPower]

Since I just had the pleasure of taking my transmission apart I can tell you exactly what that is. Each hub/sleeve has 3 of these spring loaded balls. BRBA02 in the diagram.

[ls1ac]

Yup, a detent ball. That is good as the trans did not self destruct.

[AxisPower]

Just to avoid confusion, these are different from the detent balls that sit inside the shiftfork shafts. Those are much bigger than the one in OP's picture. Only way I could see this happening is if somehow the transmission sleeve got pushed too far on the hub allowing the ball to shoot out. I'm really amazed that you have no problems shifting because usually the spring gets stuck in a weird way between the hub and sleeve with no ball to keep it compressed.

[Molez93]

Originally Posted by AxisPower

Just to avoid confusion, these are different from the detent balls that sit inside the shiftfork shafts that some people might have seen when putting in mtec springs. Those are much bigger than the one in OP's picture. Only way I could see this happening is if somehow the transmission sleeve got pushed too far on the hub allowing the ball to shoot out. I'm really amazed that you have no problems shifting because usually the spring gets stuck in a weird way between the hub and sleeve with no ball to keep it compressed.

Yeah... Weird to have that appear as my first sign of an issue. Noticed Western NY in your signature/ profile. Any chance I know you from SCCA events, but obviously not from your forum name?

[ROADRACER]

Originally Posted by AxisPower

Just to avoid confusion, these are different from the detent balls that sit inside the shiftfork shafts. Those are much bigger than the one in OP's picture. Only way I could see this happening is if somehow the transmission sleeve got pushed too far on the hub allowing the ball to shoot out. I'm really amazed that you have no problems shifting because usually the spring gets stuck in a weird way between the hub and sleeve with no ball to keep it compressed.

I just joined this club. I was just planning to change to a different fluid in my track car due to the shift quality deteriorating a bit. It still shifted ok, but if I didnt rev match well it would grind a little.

I found 2 of these balls on my drain plug magnet. I assume they are in the transmission for a reason. Do these detent ball keep the tranny in gear after the shift? I also assume I would be destroying whats left of the transmission if I continued to drive it.
Any info or advise from the OP or Axispower would be appreciated.

[Molez93]

OP here... No meaningful insight beyond the replies to the thread. FWIW, mine has been fine since the fluid change (and before) and I've done nothing "new" to it. Last summer included its typical usage of ~6 autocross events and a single track event. Other use was travel to and from those outings plus a little bit of tooling around town (maybe 1,000 miles).

[ROADRACER]

Originally Posted by Molez93

OP here... No meaningful insight beyond the replies to the thread. FWIW, mine has been fine since the fluid change (and before) and I've done nothing "new" to it. Last summer included its typical usage of ~6 autocross events and a single track event. Other use was travel to and from those outings plus a little bit of tooling around town (maybe 1,000 miles).

Thanks for the reply. It is a little surprising you haven't had any trouble with the tranny since discovering the loose ball. It makes me even more curious what their purpose is. If I had to guess I would say maybe they help hold the tranny in gear after a shift? Without them the gear is just held in place by the shifter fork?
I am thinking I will find a used transmission and swap it just so I don't have this in the back of my mind when I am on track running hard.

If I ever pull this tranny apart Ill post up more info and pictures.

[Matt93SE]

This is a longshot based on the size of the bearings, but Nissan FWD cars used to have problems with their input shaft bearings coming apart due to lack of a pilot bearing. Lots of vibration on the input shaft at high RPM would cause the bearing cages to break apart and eventually the balls to fall out into the bottom of the trans and the input shaft would wobble pretty bad, causing fluid leak at the front seal.

The balls from the bearing were quite a bit larger than what you have pictured, but the shift detent balls that had to come out to split the case were indeed the same size as the ones you have pictured.. (Again, that's a Nissan tranny from the '90s.. but in the end all of these we're talking about are made by Aisin, so it's possible they share some design similarities.. )

Regarding the shift detent balls... do all gears "sit and stay" when you shift into each gear? their function is simply to provide some stiffness to hold the shifter in places once you shift into each gear. if your trans likes to pop out of a certain gear too easy, then it's possible one of them has come out for some reason. it's also possible (but unlikely) that the factory dropped one inside the trans during assembly. usually those don't go in until the case is together and the shift rods are in place, so one falling inside the trans doesn't seem likely to me.

then again, I've seen stranger things!

[Molez93]

Perhaps my tranny has been misbehaving since I bought it, but... Having owned and autocrossed a couple dozen (I think) cars, I have not noticed anything unusual with my BRZ thus far.

[Matt93SE]

Originally Posted by Molez93

Perhaps my tranny has been misbehaving since I bought it, but...

I could go soooo many places with that quote. But I'm new here, so I won't...

[soundman98]

Originally Posted by Matt93SE

I could go soooo many places with that quote. But I'm new here, so I won't...

clearly, someone hasn't learned proper tie-up procedure!

[radon55]

Originally Posted by Molez93

Perhaps my tranny has been misbehaving since I bought it, but... Having owned and autocrossed a couple dozen (I think) cars, I have not noticed anything unusual with my BRZ thus far.

Did you have anything come of this random detent ball?

I just had this happen when changing my trans fluid today. Just one single ball on the drain plug like you.

[Molez93]

Originally Posted by radon55

Did you have anything come of this random detent ball?

I just had this happen when changing my trans fluid today. Just one single ball on the drain plug like you.

Nope. Nothing.
Keep in mind, my car may have been a bit more difficult to shift from the day I bought it. Once the tranny fluid is warm, it’s no longer notchy or just a bit difficult to shift. Frankly it felt normal day 1 and has ever since, but maybe other twins are better. IDK

[radon55]

Originally Posted by Molez93

Nope. Nothing.
Keep in mind, my car may have been a bit more difficult to shift from the day I bought it. Once the tranny fluid is warm, it’s no longer notchy or just a bit difficult to shift. Frankly it felt normal day 1 and has ever since, but maybe other twins are better. IDK

Well that's good. Glad it's still going!

I did a track day last weekend and I think the shifting was fine. Maybe slightly more difficult to go 3rd to 4th, but might have just been a mental thing since it was my first track day of the year. Hoping mine lasts without that random detent ball too lol.