2G Transmission axle seals leaking

[Xarzor]

So I just put OEM axle seals in the transmission. Installed them with a seal installer and lubed the outer seal with transmission oil and installed the axles. Took it for a five mile drive and leaking terribly. So bad it's running down the bottom of the car.

OK back story. When I bought the car the axle seals were not leaking but I had to change the CV axles because they were slinging grease. I bought O'Reilly brand CV axles and O'Reilly brand axle seals, because I thought might as well change them not knowing when they were done last. I also switched to Redline 75-90 oil. Within a few days of doing this the axle seals started to leak. But It was just a few drops on the floor of the garage after driving to and from work. I thought it might have been the cheap seals so after a few months I ordered OEM axle seals and chaged my oil to Redline MT-90. And after five miles it's practically just pouring out.

What's the problem here? It's just a lip seal and I know I installed it correctly. I've done dozens of these on different applications with no leaks. The only thing I can think of is the diameter of the cheap CV axles are smaller then OEM.

Thoughts?

 

[luv2rallye]

The seal flat side goes out - U shaped side goes in. Also many manuals say put oil on the seal before installation. Well on the very inner diameter edge (that rubs on the shaft) is ok but not on the seal outside circumference. Remember if it slides in easily (because you put oil on the outside circumference), it also will slide out (or leak) easily. Instead put a very thin layer of black oil resistant RTV (I prefer) on the outside circumference just before installation. Here's a video, although he uses lock tite (see timestamp 3:10):

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[pauleyman]

Both seals or just the passenger? Any chance the passenger side got a fwd seal by mistake?

 

[Jon Lane]

Both seals or just the passenger? Any chance the passenger side got a fwd seal by mistake?

Both sides, both times. I'll go hunt up the respective part numbers.

The first set were an unknown variety, black, installed by the high-end DSM gearbox shop. The second set I sourced and are all OEM. My situation is starting to resemble the OP's...

There's excellent advice in this thread: Depth to install and the weep hole at 12 on the clock. WIll review that this week with the local shop who did the work.

There was a remark about bearings too. It bearings are out of spec, might the axle deflect enough to leak? How about when the car is off and stationary, because that's when this one likes to drip. Does it sag and open up the seal?

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[97egl]

STM Tuned has a nice dropdown box and pictures of what the seal you need will look like for each side. Hopefully this helps

Mitsubishi OEM Axle Seals for DSM

Genuine OEM Mitsubishi factory replacement axle seals for all 1990-1999 1G/2G DSM auto and manual transmission models. There's only 3 different seals, but they fit in various places for AWD, FWD, front, rear, left and right. Just select which seal you need. Sold individually as needed, price is...

stmtuned.com

 

[Jon Lane]

Seals to replace the leaking black ones were MD707184 and MD719710.

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[Jon Lane]

Had a long conversation this week - OEM seals can be black. Also learned that the driver's side has a weep hole and it's keyed opposite the notch in the steel housing. The notch goes up. The pass side has no hole.

My passenger OEM replacement is leaking just like the one it replaced. The driver side looks dry. Still trying to figure this out.

 

[twicks69]

Had a long conversation this week - OEM seals can be black. Also learned that the driver's side has a weep hole and it's keyed opposite the notch in the steel housing. The notch goes up. The pass side has no hole.

My passenger OEM replacement is leaking just like the one it replaced. The driver side looks dry. Still trying to figure this out.

How far are you driving the seal into the case? Show me a good close up photo.

 

[Jon Lane]

Does anyone have the specified axle diameter at the seal surface handy?

 

[Jon Lane]

The pass side seal is seated flush. Its little circular rubber ridge fits up inside the corresponding circular groove in the CVJ. Neither sealing surface is compromised, at least not with the car on the hoist and the mechanic pulling it back and forth as hard as he can. Rock solid.

But it's still wrong. Our thought now is that the axle clip isn't holding properly and eventually the inside CVJ is riding too far inward. Do the circular clips fit a groove or do they just overhang a ledge and the axle can continue to move in?

Has anyone had a circular clip fail to hold the axle stub in place where the CVJ expansion pushes it in too far?

Seals and seal mating surfaces are fine. Two new axles and three new OEM seals have been tested.

 

[Jon Lane]

Apparently TRE can't be bothered to call me back, so I'll try again:

Do the circular axle stub clips fit into a groove in the transmission output to prevent side to side motion or do they just overhang a ledge so the axle can continue to move inboard?

Has anyone had a circular clip fail to hold the axle stub in place where the CVJ expansion pushes it in too far? The clips on these axles don't look or feel very adequate.

 

[Jon Lane]

I guess nobody knows. Maybe I'll try an auto axle because it's 7/16" shorter.

 

[twicks69]

If you are using new circlips, there should be no issue unless you have a bearing failure at the front differential with the axle and differential flopping around. The axle stub passes through the pinion gear on each side and there is a circlip on the right axle to retain it on the inner edge of the pinion gear. It should physically click in and be held in place. If you can literally install your axle by hand and not have to slam it into the gear, then there is an issue. This could also be a front differential issue internally if you have tried several model specific axles and all are having the same issue.

 

[Jon Lane]

If you are using new circlips, there should be no issue unless you have a bearing failure at the front differential with the axle and differential flopping around. The axle stub passes through the pinion gear on each side and there is a circlip on the right axle to retain it on the inner edge of the pinion gear. It should physically click in and be held in place. If you can literally install your axle by hand and not have to slam it into the gear, then there is an issue. This could also be a front differential issue internally if you have tried several model specific axles and all are having the same issue.

Axles and clips are new. The outer seal is riding up in the corner where the seal shaft meets the vertical flange, so the right axle seems long. (Car is somewhat lowered and has Volk LCA, which may be contributing, but that same setup was on the car for years prior with no problems.) Only the axles changed with this rebuild.

Left side is fine. Left side is also radially tighter when you pull hard on the axle from under the car - I'm told the right sides are always looser because they're the ones that transmit deflection directly back into the transmission. Left sides are buffered by the intermediate shaft. But the right side also gives less axially than the left.

The transmission is fresh from the rebuild but its not a new transmission and whether TRE inspected the differential assembly for excess wear is unknown. Flying blind here. What's odd is how the thing is leaking like this. Almost nothing comes out driving but a lot does when stationary and cold. Beats me.

We're installing an auto axle on the right side. They're about 7/16" shorter. If this relieves the whole apparatus and puts the seal back further down the shaft where it belongs, that seems like a good thing. We'll also measure both axles and compare to spec.

Thanks for the input. I'll PM you too.

 

[Jon Lane]

I have an update for the thread. First, apologies if I've shifted the topic. I thought this was a good place to post how this particular saga was going, given that it is also about a leaking axle seal. I'm just not the OP, so pardon the extension of the thread.

I believe we have a working conclusion as to why this seal is leaking. First some questions: Are seal housings steel? I can't imagine them being a soft metal and holding their shape so steel seems a fair estimate. And: how are the bearings at the transmission outputs typically removed? I assume their races are pressed in.

I'd appreciate some transmission experts chiming in. With this perspective I can relate what we've found. It isn't axles and it's not even sealing axles to seals, of which we've not replaced three OEM seals with three more OEM seals.