Leaking transmission fluid

[Okie Boarder]

It looks like I may have developed a transmission leak. I noticed a bit of fluid in the bilge Saturday at the lake. The bottom of the transmission case is a little wet with it but it wasn't crystal clear where it was coming from. I plan to dig into it this week to see what it's going to take to fix it. For those of you that have worked with the transmission, can you tell me where the various seal points are? Are there bolted areas with gaskets that just might need to be snugged up? Is there only special seals that require removal of the transmission?

For reference, it is an 89 Supra Sunsport with the PCM 40A 1.23:1 transmission.

[DAFF]

Sound like the seal on the ouput shaft has spring a leak. Clean the area using some brake clean and inspect when on the lake. Not a big job but you need to pull the prop haft away from the trans.

[trayson]

Welcome to the club. Don't let it get low when you run it.

Skidim has a seal kit that contains everything for like $175. Might be worth calling them to see if you really need the whole kit. After you pull the tranny, you'll need to do the engine/tranny/prop shaft alignment. There's a great youtube video on this done at a Natique owners event.

Also, it's interesting to note that my owners manual told me to check my fluid level with the engine off, yet when I downloaded the service manual for my PCM 40i that it told me that I needed to check the fluid with the engine RUNNING and on the water in neutral.

Check this out, it might be helpful:
http://engines1.novosolutions.net/de...62&Lang=1&SID=

I was told by Ski DIM that I should check my engine/tranny/shaft alignment because if I'm off, then that's a way that seals will get worked out of place. Also I was told to pull the starter and look in there to see if there was tranny fluid as that would let me know if it was leaking into the area around the flywheel.

[lively]

Okie I would say your shaft seal is prob leaking thus dripping down the bell housing . Like 12 $ for the seals and most automotive parts house will have them just take them both out "front and rear" IMpact the nuts off and slap some new ones in . Do you have a dial indicator ? I found using two to align couplers are easiest compared to feelers

[trayson]

Okie I would say your shaft seal is prob leaking thus dripping down the bell housing . Like 12 $ for the seals and most automotive parts house will have them just take them both out "front and rear" IMpact the nuts off and slap some new ones in . Do you have a dial indicator ? I found using two to align couplers are easiest compared to feelers

Don't have a dial indicator or feeler gauges. Would one of the inexpensive ones from harbor freight be good enough? It's not like I see myself using these all the time!

Also, as best I can figure out, I suspect that the leak might be where the tranny connects to the bell housing. reaching way under there, it seemed like one of the few places I was able to find a little residual fluid. So, that's my best guess right now. I've had a couple people tell me that they suspect my engine/tranny/prop alignment is off, so that will be something I will have to check.

Of course the boat's been giving me other issues too, so it's hard to find time to be a boat mechanic in all areas...

[rideevol]

I have the same transmission. 89Mariah. My leak started from an overfilled transmission caused by a rudder area hull breach. Long story, almost sunk, happy ending.
Somehow water entered transmission. Repeated drain-fill-run in the yard saved the internals, but tranny leaked fluid from then on. My case seal was the part that needed replacing, the green gasket in the skidim expensive gasket kit for the 40A. It wasn't the front or rear seal. Back in the lake and happy. E-mail me if you need details on transmission case opening.

[Okie Boarder]

Thanks for the feedback so far. I haven't messed with it yet to further my discovery, but plan to this evening. First thing I plan to do is to wipe it clean and see where the fluid appears to be coming from.

I've done the alignment before when I put the motor back in after my rebuild, so not worried about that. I'd love to hear more about the process of replacing the rear seal versus the front seal for anyone that wants to share.

[Okie Boarder]

So, I cleaned everything up and started looking around. There has been no evidence of any more leaking since the day in the lake. It seems the leak happened while underway, but not while sitting in the driveway. Any thoughts?

[SquamInboards]

If it's just a small leak from one of the shaft seals, you might not get enough to notice when it's just sitting in the driveway. I put a white oil-zorb pad under my transmission after cleaning the area to find the leak I had last year. After a little time on the lake there was a red spot under the front of the transmission / bell housing area, indicating a possible input shaft seal leak. Upon disassembly it definitely was wet all around that seal. Simple replacement and no leak since.

[Okie Boarder]

We went to the lake Saturday and kept an eye on it. We neded up leaving the lake a bit earlier than we had planned and the last time we checked it hadn't leaked. When we were cleaning up the boat at home we found some transmission fluid in the bilge when we removed the front ballast bag. We checked the transmission and it appeared to be coming from the rear. It is less fluid than last time, but we weren't out all day. Next time out, I think I'm going to put an oil-zorb pad on the bottom of the transmission to soak it up and see if it is for sure in the rear.