Terrible Transmission Leak on 03 manual TDI

[FluffySmooth]

Hello all! I have been with this site for a while now, but here is my first post. I have a 2003 5-speed TDI Jetta and I am having a terrible transmission leak problem. It has been leaking a small amount for half a year or so, and I could never find where it would leak from. I would usually add transmission fluid every oil change (every 5k miles). Usually not even half a quart at a time. I have been running Valvoline Synchromesh. About 2 months ago, I determined that I thought the driver's side axle flange seal was the culprit of my leak. So, I replaced it with a brand new one. That was not the issue apparently. Today I have determined that it seems to be coming off the top of the transmission and falling down the transmission. After that, of course, all over the undercarriage and out the back.

My initial hypothesis is that it may be the shifter linkage seal? Looking to see if anyone else has had this issue. If we suspect it to be the shifter linkage seal, where would I find one to purchase? The little searching I've done so far has not been successful.

Additionally, everyone on this site seems to have mixed feelings on their favorite transmission fluid from the OEM fluid to Redline and more. My Valvoline Synchromesh is quite thin. Is this Synchromesh "thinness" hurting me as well?

I have tried to provide pictures below as well. I am not sure how to share pictures within the post, so I have provided a link to a shared Google Drive folder. They were all taken today. It's been driven about 2k miles since I checked the transmission fluid level. I have watched closely, and only today has it been this bad of a leak. It is so bad it is peppered all over the back of my car. Thanks to all in advance for their assistance.

https://drive.google.com/drive/folders/1SEEDJ8i-NdO3MuRGdeZAcDx5tNg36_oL?usp=sharing


UPDATE: I cleaned it off top and bottom, drove it to work and back (about 20 miles either way) and it looks just as bad as before I pressure-washed it. Still coming off the top of the transmission somewhere. Still think it is the shift tower. IT IS NOT OVERFILLED

UPDATE 3/25: Cleaned it again and drove it just up the road and back. I definitely looks like it's leaking around the Axle seal now. Frustrating because I replaced the axle flange seal not 5k miles ago. I wonder if there is a larger problem with something besides the seal? I just ordered another seal from ID Parts and will have to put it in. Last time around I put RTV around it too so it would seal up better.


UPDATE 4/18: It has been a while since I worked on my car, but I thought I was post an update in case anyone else runs into this problem in the future. After I installed the new Axle flange and seal, I got the inner CV joint reattached and noticed the flange has some play in the transmission. The flange can be slightly "jiggled" in any direction. Everything was tightened down properly, but it still had some play to it. This means it is is most likely something like the bearing around the differential. This is the noise I am hearing, and it is most likely why my transmission leaks.

 

[snakeye]

How are you measuring the fluid level to determine the amount that needs to be added? Maybe you're overfilling the transmission?

Also, why 5k mille oil changes???

 

[STDOUBT]

Advise to make sure the wetness isn't coming from your coolant temp sensor.
Coolant could be combining with the dirt on the engine to appear like oil.
As for gear oil, if you can find the original G005000, why not use it?

 

[Mpaw]

Could be that you are causing this problem.
VW state that you should never top up transmission oil. The only way to 'top it up' is to drain it all and measure exactly how much you put in.

 

[Tdijarhead]

I tried Valvoline Synchromesh for a short time and I didn’t like it as well as Penzoil synchromesh so I switched to Penzoil. The synchromesh allows for smoother less notchy shifts over the oem stuff. Synchromesh can smooth out the shifting of a transmission that has accumulated some miles.

It would be hard to overfill the transmission on one of these. In fact a bit of an overfil is way better than an underfill which can leave your fifth gear high and dry so to speak.


I have not heard of the shift tower leaking, but since the shift tower comes out I would assume that there is a seal or O ring of some kind that the tower slides through. Any seal or O ring is capable of leaking. If you are consistently adding oil to the transmission and it’s not coming from the valve cover or isn’t coolant mixed with dirt and from your pics it appears to be fairly clean oil which means it’s not engine oil. I would check that seal. Check the tdi 101 section under the diy yourself heading there may be a write up on the shift tower.

 

[Mpaw]

" In fact a bit of an overfil is way better than an underfill which can leave your fifth gear high and dry so to speak. " not according to VW...........

 

[turbocharged798]

Yeah I completely disagree with that statement about its better to overfill. I find that overfilling causes the fluid to overwork heat up and burn. After taking a transmission apart that has been overfilled, its filled with brown goop all over the place and you can smell the burnt oil.

 

[Tdijarhead]

It is hard to overfill these transmissions, jacking it up as if you’re changing a tire allows you to put almost the entire contents of the recommended 2 quarts in the gearbox as opposed to filling it level and getting in about 1 1/2 quarts which would be an underfill . I would rather get the entire 2 quarts in so that 5 gear doesn’t lack for lubrication. To get more than 2 quarts in you would have to stand the transmission on it’s side.

 

[oilhammer]

I would think if it was leaking that bad, you should be able to find the leak fairly quickly.

I don't think you could overfill it enough to have it blowing out the vent unless you stood the car on its butt and filled the gearbox that way.

 

[FluffySmooth]

How are you measuring the fluid level to determine the amount that needs to be added? Maybe you're overfilling the transmission?

Also, why 5k mille oil changes???

I am filling the transmission through the plug in the front. I fill it up to the hole. I don't really think I am overfilling it.

Additionally, what is wrong with 5k mile oil changes? Too infrequent or too frequent?

 

[FluffySmooth]

Advise to make sure the wetness isn't coming from your coolant temp sensor.
Coolant could be combining with the dirt on the engine to appear like oil.
As for gear oil, if you can find the original G005000, why not use it?

Hello. The fluid really feels and looks like my transmission fluid to me, but I will look into the coolant temp sensor as well. And yeah, I should probably get the original fluid.

 

[Genesis]

Pretty hard to overfill a MTX since it all just leaks back out while you're putting it in.... I've got a small weep in mine which I suspect is the driver-side flange, but haven't changed it yet. Next time I have a reason to take the joint off I will though (likely either clutch or CV boots) It's not enough to change the level by a material amount over tens of thousands of miles however...

 

[FluffySmooth]

I tried Valvoline Synchromesh for a short time and I didn’t like it as well as Penzoil synchromesh so I switched to Penzoil. The synchromesh allows for smoother less notchy shifts over the oem stuff. Synchromesh can smooth out the shifting of a transmission that has accumulated some miles.

It would be hard to overfill the transmission on one of these. In fact a bit of an overfil is way better than an underfill which can leave your fifth gear high and dry so to speak.


I have not heard of the shift tower leaking, but since the shift tower comes out I would assume that there is a seal or O ring of some kind that the tower slides through. Any seal or O ring is capable of leaking. If you are consistently adding oil to the transmission and it’s not coming from the valve cover or isn’t coolant mixed with dirt and from your pics it appears to be fairly clean oil which means it’s not engine oil. I would check that seal. Check the tdi 101 section under the diy yourself heading there may be a write up on the shift tower.

Yeah I actually have a new valve cover on it. I have been monitoring it closely and it does not seem to be leaking there. I will look into the shift tower seal/o-ring.

 

[FluffySmooth]

Pretty hard to overfill a MTX since it all just leaks back out while you're putting it in.... I've got a small weep in mine which I suspect is the driver-side flange, but haven't changed it yet. Next time I have a reason to take the joint off I will though (likely either clutch or CV boots) It's not enough to change the level by a material amount over tens of thousands of miles however...

The driver's side axle flange seal was super easy to change! And yes I don't see how you can over fill one...

 

[FluffySmooth]

Could be that you are causing this problem.
VW state that you should never top up transmission oil. The only way to 'top it up' is to drain it all and measure exactly how much you put in.

Interesting. You may be right. I never thought to measure it. VW says 2 quarts right?

 

[oilhammer]

Capacity is 2 LITERS.... it's a German car

 

[FluffySmooth]

Capacity is 2 LITERS.... it's a German car

Oh right lol, liters haha

 

[snakeye]

Oops completely forgot your can't overfill the gearbox. I think the only way of actually getting 2 liters in there in the first place is by raising the front end.

To answer your question about the oil change, the interval is 10k miles, so provided that you're using the proper oil for your engine, more frequent changes aren't really necessary.

 

[pkhoury]

On the note of fluids - I took @Whitbread 's suggestion and used Redline Lightweight Shockproof instead of the Febi Bilstein GL-4 I was using before, and my transmission shifts SOOOOO much better than before.
I wasn't having leaks, but I was concerned about water intrusion before. I actually replaced a lot of my plastic coolant hoses (because they like to break after 20 years).

 

[turbocharged798]

It is hard to overfill these transmissions, jacking it up as if you’re changing a tire allows you to put almost the entire contents of the recommended 2 quarts in the gearbox as opposed to filling it level and getting in about 1 1/2 quarts which would be an underfill . I would rather get the entire 2 quarts in so that 5 gear doesn’t lack for lubrication. To get more than 2 quarts in you would have to stand the transmission on it’s side.

1 1/2 quarts is about what you get out of drain and refill. The rest sits in the 5th gear area. Pull the cover and you will get another 1/4-1/3 of a quart.

If you are putting in a two full quarts on a change then it is being overfilled. Bet the fluid will look like mud when it drains out.

 

[Tdijarhead]

Hmmm, never had an issue with it looking like mud. I’ve used that same method on several vw’s and have yet to see anything approaching mud when I go back in 100k miles later to do another drain and fill.

 

[turbocharged798]

That's been my experience anyway. Since been careful at filling them now fluid comes out looking nice and clean.

 

[norbert77]

" In fact a bit of an overfil is way better than an underfill which can leave your fifth gear high and dry so to speak. " not according to VW...........

Remember, every recall and TSB was once approved by the auto engineers.

 

[burn_your_money]

Get a hot water pressure washer in there top and bottom. Drive it home and you should be able to clearly see where the leak is originating from. You can get some dye to put in the oil to help locate it if you need to.
As for fluid, I recently used Redline MTL and was extremely happy with it.

 

[jokila]

Yeah I completely disagree with that statement about its better to overfill. I find that overfilling causes the fluid to overwork heat up and burn. After taking a transmission apart that has been overfilled, its filled with brown goop all over the place and you can smell the burnt oil.

I don't think you can get enough lube into the 02J.

Remember, every recall and TSB was once approved by the auto engineers.

Those same engineers made the 5th gear a weak link in the lubrication.

Hmmm, never had an issue with it looking like mud. I’ve used that same method on several vw’s and have yet to see anything approaching mud when I go back in 100k miles later to do another drain and fill.

I had some foul smelling, somewhat muddy oil when I changed it once back in the day. Turns out the selector shaft bearing had worn causing the shaft seal to tear apart allowing some water to enter. Where I live there is a lot of rain and I didn't often avoid the deep water either.

 

[Genesis]

Never had anything nasty come out of mine; I usually change MTX oil on 50k intervals.

 

[norbert77]

If you have a mystery oil leak,. Spray her dowqn good with a degreaser, drive to diy carwash, spray degreaser again, and hose off. Should be ni e and clean after

 

[AndyBees]

Below is what your transmission will look like when run low on oil and contaminated with water. This is the transmission in my 2000 Jetta TDI in 2011 at about 250k miles with no changes or top-offs. The 5th gear Slider and Hub were worn so bad it jumped out of gear with no warning and I never could get it to stay in 5th gear again. I ran a 5th gear out of a gasser transmission until I found a replacement. Today, after several flush changes, the transmission is doing fine at about 380k miles on it (my son owns now). The last two changes, I put Penn Syncromesh in it.

 

[Tdijarhead]

Sometimes engineers can get it wrong or only half right. I suppose that’s why TSB’s and new and improved or corrected parts are placed into service during a recall. Here is a link to an older thread that outlines how to correct the lubrication mistake or perhaps partial mistake the engineers made on our manual transmissions. It makes for interesting reading, and has pics to illustrate the procedure.

02J 5th Gear Lubrication Modification

Here's an invaluable how to to modify the 02J case in improving lubrication to the 5th gear area. This photo is the case as it is before modification. In the area marked, take a 1/4 inch drill bit and drill holes, pushing to the side to make a large oval for the port in the middle. The final...

forums.tdiclub.com

 

[FluffySmooth]

I think we can rule out overfilling the transmission. Just doesn't seem possible. I washed it off yesterday top and bottom with a pressure washer and Simple Green. I'll drive it a day or 2 and see if I can find the culprit.