borg warner shaft gasket/ seal leaking

[jointcustody]

Hi there,

I am wondering if any of you have had this leak before. It appears to be a minor transmission oil leak on my borg warner transmission right where it outputs to the main shaft. If you look closely you can see where it is slinging oil as the shaft turns- a perfect oil ring

Is this a gasket or oil seal? simple fix or no? Can I take this apart in the water?

Thanks.

 

[Bmarler]

I had that happen on a different brand gear before. I’d imagine it’s going to be similar. The rear seal is going out. I replaced mine while out of the water and servicing the shaft log, but you can do it in water if there’s enough room to slide the shaft back and make room to work.

 

[jointcustody]

Awesome thank you. I guess just a marine tranny shop for a seal?

 

[twistedtree]

Check out Michael woodring’s YouTube channel. I think it’s boat divers guide, or something like that. He just finished rebuilding what I think is this exact drive. If it’s just a rear seal replacement, it might be very easy.

 

[Bmarler]

Awesome thank you. I guess just a marine tranny shop for a seal?

It should be a standard size seal. Most industrial supply houses should be able to get it for you. Places that sell sprockets, bearings, etc…

 

[Cigatoo]

You probably already checked this but in the case that you have not...
Make sure that the dipstick is fully in and tightened. Its a rubber plug that expands when you turn the handle. If you don't tighten the dipstick it will leak out the top. The fluid runs down underneath and finds it way to right under the rear seal making the rear seal appear to be leaking. Ask me how I know. Was a good day when I realized my leak was "operator error"

 

[Island Cessna]

It could also be the big nut holding the flange on the output shaft coming loose. This allows oil to come down the splines and out between the two flanges. Easy trouble shooting. The oil will sling off from the joint between the flanges, not the forward side of the output flange, plus if you unbolt the two flanges there will be oil in the cavity between them. If this cavity is dry then you know it is the shaft seal on back of the gearbox.

If the nut is loose tightening it is urgent before the splines are damaged, but if you catch it in time it should be a simple matter of retightening the nut, and resecuring its lock.

 

[jgwinks]

I have the same gears in my boat, and one had the same leak. I uncoupled the shaft to get a better look and found the engine was WAY out of alignment. We realigned it and the leak stopped. About 100 hours running since and not a drop. Must have been side pressure on the seal causing it to leak that went away when aligned.

 

[JMcJ]

Likely the front seal on the transmission has failed. A fairly easy fix and can be done in the water. Our 36GB single had more than enough space between the cutluss bearing and rudder to allow the transmission to be slid free of the engine drive shaft. You will probably need to uncouple the drive shaft from the transmission. The seal can be removed and replaced with the transmission on a 2x10 across the stringers. We decided to lift it.
Two points: 1. If your rear engine mounts are attached to the transmission, they will have to be undone and the rear of the engine supported.
2. If it has not been done very recently, absolutely replace the damper plate while the transmission is off.
Will try to attach photos.

 

[Gdavid]

It could also be the big nut holding the flange on the output shaft coming loose. This allows oil to come down the splines and out between the two flanges. Easy trouble shooting. The oil will sling off from the joint between the flanges, not the forward side of the output flange, plus if you unbolt the two flanges there will be oil in the cavity between them. If this cavity is dry then you know it is the shaft seal on back of the gearbox.

If the nut is loose tightening it is urgent before the splines are damaged, but if you catch it in time it should be a simple matter of retightening the nut, and resecuring its lock.

I had the exact same situation on the same transmission. It is just like the pinion nut on a rear differential. Simply grab the shaft and try to move it around to diagnose.

 

[JMcJ]

Here are the photos

 

[jointcustody]

"Make sure that the dipstick is fully in and tightened..."

- The dipstick is looking a little worn out, and I had suspected it at one point but then tightened it extra and it seemed to not leak, but I will definitely check this.

"It could also be the big nut holding the flange on the output shaft coming loose. "

- I'll check this

"...I uncoupled the shaft to get a better look and found the engine was WAY out of alignment...."

- I guess you would be able to diagnose that its out of alighment when you disconnect the flange, and see the gap? if one sides touching or flexing and the others not?

"...Likely the front seal on the transmission has failed."

- there has been no oil under the tranny from what i could tell, so I am thinking by front seal you mean where it attaches to the engine?

Thank you all!

 

[JMcJ]

If you use ATF in your transmission instead of 30wt oil, and it is transmission fluid you are seeing, then I would lean towards a leaky seal being the cause. In any event there is a dye you can add to the fluid which will help to isolate the cause. On Unicorn, it was apparent at the joint between the transmission and the bell housing.

 

[Capt.Sam]

Borg Warner's have 2 seals, 26 spline input shaft(goes into drive damper) and output (mates to shaft coupling), as a previous member suggested, remove the transmission (since your's is a drop center gear), if you don't have enough room to slide shaft back to remove nut and coupling. Inspect coupling "sealing diameter " for necks, burrs, or sharp edges, which might damage new seal, or prevent proper sealing. Surface rust can be removed with emery cloth or sandpaper. Lubricate "sealing diameter" with ATF, when reassembling, new seal should be flush with end of reduction gear case, align splines on coupling to those on the main shaft, press coupling until contact is with bearing inner race. Assemble main shaft nut and tighten to specified torque. Refer to your Borg Warner owners/service manual.
As mentioned earlier, check your engine alignment, if you remove transmission, because the rear motor mounts are on the transmission. As a general rule of thumb, .001 per inch of coupling diameter, for alignment tolerance.

 

[Darlin]

Tranny Leak

Be sure to keep tranny fluid topped up and don't defer seal replacement. I had a leak develop into an fluid pump replacement because of gaulling and overheating.

 

[jointcustody]

So for an update....

I ended up buying some oil dye for the transmission. We ran it after for a good while in gear to get it warm then shut engine room lights off and used uv flashlight to look for leaks. At this point could no find any- after we had tightened the dipstick very well.

We are going to monitor it for the next while.

Thanks for all your help, and if it does leak again i will update once more.