Do you really need to drain the transmission to change the clutch?
 

I just put a fresh fluid change of motul300 in my brz.
Not long after, I realized that I have to change the clutch.

Do you really have to drain the entire transmission before changing the clutch?
It seems like a sealed system to me, and I don't know where the fluid would come out of where it wouldn't be a problem while the transmission is in.

It's not going to come out of the clutch area, maybe the driveshaft seals it?

IDK.

I guess, since I just did it, I can drain it into a clean container, get a quart extra just in case, and re-fill it if ABSOLUTELY necessary.

It just seems like ina ll of the clutch replacement guides I see, draining and filling the trans is just because it's a good time to do it, rather than something that is necessary because trans fludi will be spilling everywhere.

Anyone know this?

Thanks!

Yes, it'll come pouring out the back if you don't drain it. Even after draining, it's still a bit messy.

Just save it in a clean container and reuse if you want.

Everything he said. If you can find a way to plug the entry point where the driveshaft enters the casing you COULD skip it but I wouldn't want to press my luck with that.

And it IS mentioned in the service manual. Screen grab attached.

Thanks guys!
Definitely draining it now.

I replaced my TOB and did the clutch while I was in there without draining the transmission. Bought this : https://www.amazon.com/gp/product/B000P0U04G to keep the fluid in the trans after pulling the driveshaft. You do need to be careful and try to make sure that the tail stays inclined a bit so that it doesn't want to leak, but it's do-able.

It's sort of 6 one/half dozen the other. I didn't really have a good containers/etc to re-use the fluid, and like you had just swapped it. Leaving the transmission filled does add some complexity to the job though.

Nope. Leave the driveshaft in the transmission. Run some zipties around the tailshaft and through the uv joint to make sure it stays in.

It makes the transmission more cumbersome to deal with, but it can be done this way.

I've considered this. Dismissed it for being too awkward. I'll give it a try next time.

I'm going to try to leave the driveshaft in.
I'm going to rent a bay to do the job, so I don't know how awkward it will be to let the driveshaft dangle, or if it will throw the jack off balance, as I know that the transmission only weighs 80 pounds.
After looking into it, the driveshaft weighs 24, so it shouldn't be too bad.

If I can do it on a lift, I'd assume that it would be much easier to do it on jackstands a few inches off the ground, because the driveshaft would not be able to dangle as much.

In either case, I'll take pictures if I do manage to do it!
If not, and if it starts to feel really wonky, I'll just drain the transmission.

Definitely be careful of the transmission being off balance doing this on a lift. Even on jack stands the driveshaft has some awkward pendulum action when pulling the transmission and putting it back in.

If I was doing this on a lift, I’d be sure to strap the transmission to the jack and I think I’d try something like using a loop of rope to hang the end of the driveshaft a few inches below the diff. Just enough to let it move freely while pulling the trans off the clutch, but not enough to imbalance the jack. Not sure this would work, just having a thought.

On a video that I saw, the guy used a deep socket that had the OD of the driveshaft yoke and then put a 1" extension in the other end of the socket. I did my clutch this way and it works.

A 3d printed plug would go a long way for this ...

Ok. So so far the transmission is out, new clutch inst
alled, etc.
I did leave the driveshaft in, and it was fine with tbe transmission strapped to the jack.
I did not have to drain my transmission.
However, when i removed the bearing retainer cover, about a 1/2 cup of fluid came out of the lower bolt hole.
I had to screw it back in and lean the transmission back a bit.

However, the frame for the shifter will not come out without removing the driveshaft.

I just have to put it back in.
I told myself that i was going to go fast, but ended up taking my time for a lot of things like making sure the bolts for the bearing retainer cover were free of sealant, prepping surfaces, making a good bead with sealant, replacing the tob and rhe clutch fork, and I did a lot of things like replace the rear main seal, all of my shifter bushings, etc.

Ill post a bunch if pics after im done tommorrow.

oh the irony of how one would design such a plug

WTF... You said "change the clutch," not "take apart the transmission." Of course you have to drain it if you're going to take it apart.


Better de-grease and seal the new front cover with the right stuff if you don't want it to leak.