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  #1  
Old 05-07-2011, 05:52 PM
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My Transmission is still leaking and I've tried everything.

Hi, I've been trying to get rid of this leak in my transmission in my '87 TD for the last year. I changed the pan gasket, then the pan itself with no luck. It is only on the driver's side, where all of the pistons, linkage etc are. Now that it can't be the pan or gasket, I'm guessing it must be a seal of some sort. I put an o-ring on the large allen key plug towards the front. this did not help. Are one of these components prone to leaking on a 300,000 mile car? What can I do while the transmission is still in the car? I am about to give up and get a rebuild, even though the transmission shifts great until the fluid gets a little low. Better yet, I'll just drive in into the Monongahela. I appreciate any help. Here is a reference photo.



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  #2  
Old 05-07-2011, 05:57 PM
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I had a leak in that area and it turned out to be the reaction valve seal. Discovered it by cleaning up really well, driving a bit, then taking a look.

So re-build instead of re-seal? Maybe a re-seal with that kind of high mileage is throwing good money after bad.

How quickly are you losing fluid? I sure would be tempted just to keep pouring fluid in....
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  #4  
Old 05-07-2011, 06:50 PM
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I just figured changing a 5 dollar seal along with a few hours of labor would be worth it. If it is one of those things that requires removing the transmission, then I will consider a rebuild. A rebuilt transmission is 1400 for this car.

I have not tried Trans-X i Have read mixed reviews on stop leaks in mercedes. most people say stay away from them. I tried some lucas, that didn't help. I've been putting mobil-1 in it as that is what the previous owner had in. It generally leaks an ounce or so after the car is turned off after driving. I don't think it leaks very much while I am moving. Maybe a drop here and there.

Could the synthetic fluid be a problem? I know they can cause older engines to leak when switched. Is Trans-X safe? Id rather not put a band-aide on the problem, unless it won't shorten the life of my transmission, because it does work quite nicely and doesn't flare unless the fluid is low.
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  #5  
Old 05-07-2011, 07:13 PM
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Search the forum using my name as the poster...

see other peoples views....

check older ones first... told the first experience I had with it ..Ramble....and the latest....95 Lincoln...
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  #6  
Old 05-07-2011, 07:42 PM
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Clean and dry the transmission, go for a drive, then find the source of the leak. See if it's coming more from the front or the rear. Front could be the transmission cooler line (red plug in the picture), rear could be the black piston cover in the picture. The modulator can leak but that usually causes the vacuum pump to suck ATF through VCV and mess with shifts. Maybe it's an external only modulator leak. The modulator is the turret with a vacuum line fitting ahead of the shift lever.

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87 300D
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  #7  
Old 05-07-2011, 09:17 PM
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I recommend cleaning it after you purchase a UV/Blacklight leak detector kit. If you pour a little trans fluid dye in the dipstick tube, drive it and shine the light on it to see where its coming from. It also comes in handy for suspect A/C leaks (do not use that stop leak plus tracer you can see with the naked eye ***** you get at the parts store - it wreaks havoc on the rest of the a/c system and can ruin a/c reclaim/recharge equipment), oil leaks, coolant leaks, etc. You will use it over and over again. Its one of those "must haves" for MB owners. Different dyes are for different fluids, but the light and yellow glasses work with all UV dyes.
Here is the kind I use: http://www.tracerline.com
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Last edited by mach0415; 05-07-2011 at 09:59 PM.
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Old 05-08-2011, 02:55 PM
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Quote:
Originally Posted by mach0415 View Post
I recommend cleaning it after you purchase a UV/Blacklight leak detector kit. If you pour a little trans fluid dye in the dipstick tube, drive it and shine the light on it to see where its coming from. It also comes in handy for suspect A/C leaks (do not use that stop leak plus tracer you can see with the naked eye ***** you get at the parts store - it wreaks havoc on the rest of the a/c system and can ruin a/c reclaim/recharge equipment), oil leaks, coolant leaks, etc. You will use it over and over again. Its one of those "must haves" for MB owners. Different dyes are for different fluids, but the light and yellow glasses work with all UV dyes.
Here is the kind I use: http://www.tracerline.com
I should invest in this. summer is coming, and my AC has a leak as well. I charge it and it blows cold for 3 days, then the compressor stops turning on. Definitely a leak. It would be great if the leak ends up being the tranny cooler line. Just a copper washer.
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  #9  
Old 05-09-2011, 07:33 PM
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I just want to do an idiot check to make sure I didn't mess up the pan swap.

The only time the leaking is noticeable is after driving and turning the engine off. After about 10 seconds or so oil drips off of the pan and the cable with the foam covering on the drivers side (USA) or the transmission. after a little while it stops and won't leak again until it is driven again.

A leaky pan would leak all the time, especially when warm, until the level was too low, correct?
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  #10  
Old 05-09-2011, 10:20 PM
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When I had a leak on my 82 300SD, the problem was the O-ring on the modulator valve.
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  #11  
Old 05-10-2011, 06:45 PM
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Cable with foam covering? Speedo cable?

Sixto
87 300D
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  #12  
Old 05-10-2011, 09:30 PM
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I retorqued the pan bolts. then I noticed that the leak was actually on the passenger side. I Pushed down on the piston cover on that side and it moved around! Looks like I found the leak, now what?
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  #13  
Old 05-10-2011, 11:47 PM
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Fix it

What specifically is leaking?



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87 300D
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  #14  
Old 05-11-2011, 11:33 PM
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The larger circular cover is the one that was loose. I checked it again to make sure and it wasn't loose anymore. I am going to clean it as best as I can this weekend because it is nasty. Hopefully I can make it leak in a way that doesn't splatter the fluid all over the entire transmission and maybe pinpoint it.
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  #15  
Old 05-14-2011, 03:20 PM
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well I just confirmed it. The passenger side of my transmission in caked with motor oil from the turbo leaking it through my broken exhaust flex pipe (my car has issues, but worth saving none the less). The whole side is black except for a small bit below the large circular thing in the rear. being that trans fluid is a detergent, it made sense that this was the source of the leak. I stuffed a rag up there between that spot and the chassis and viola!! I drove about 2 miles and no more leak!!!

Thanks to everyone who helped me track this thing down. Now, is there any way to fix this?

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