mj1pate

I submitted an earlier thread, but additional problems have surfaced so I've reopened with the new revelations, seeking advise.

Last year, I had the transmission lines rebuilt and reinstalled, Since then I have found no line leaks.

Recently, the infrequent drips from the transmission became a series of small puddles. The source of the leak seems to be in front of the torque converter (see picture).

Worse yet, the transmission fluid is black and has a stronger odor than fresh fluid. It was red in color last year, just after the line rebuild, 3 k miles ago. I thought maybe a cooling line was blocked, but I don't know how that would be, and the couplings at the transmission are correct.

Other than the leak, there are no transmission performance symptoms, or strange shift behavior.

Ideas? or is the transmission burned out?

mj1pate

the referenced picture is below

blown 87

If the fluid is black and burnt, the trans is likely damaged.

dr bob

^^^^ What Greg said. But, for grins, immediately swap the fluid for new, before you do more damage. Drive it a few nundred miles and change it again.

At some point very soon get the leak fixed; what looks like a small leak sitting is likely a larger leak while driving, so a lot of fluid can disappear when you don't supect it. Most folks don't check the level until they are troubleshooting slip or shift problems, by which time the low-fluid-level driving has been fatal.

mj1pate

Hi Dr Bob......encouraging words are always well received even by a dying patient

I actually have lost very little fluid,,,less than 1/4 quart, but fairly recently. The fluid level was right at the low level mark

The coincidence of this situation so close following the transmission line rebuild is grating on me. The connections at the transmission are correct. I'm very concerned about the possibility of a blockage in one of the "new" lines. I know I can test fluid flow if I know:
1) which is the return side at the transmission
2) how to hook up a flushing test line to the banjo bolts at the transmission

ideas?

But that leak forward of the torque converter, is it automatically a specific seal? or could be multiple causes?

IcemanG17

The most common leak is the main ATF pump just inside the trans near the torque convertor...but it drains down and looks like an torque converter leak

I also would change the fluid & filter......if your fluid is black and smells burnt, take a close a look at the filter...it should be clean...if there is metal or junk in it....that is not good.....

There are machines that recycle & clean the ATF by hooking into the cooler lines.....try to find a shop that can do this.....that will tell you quickly if you have a cooler blockage....

mj1pate

Thanks Iceman...one last question(s) before I go into the manuals:
1) Are the there things to watych out for w/r to the pump r/r?
2) Is the pump itself the problem and must be replaced as a unit? or is it a worn seal external to the pump?

IcemanG17

Its just a seal...pretty simple once the torque converter is out...however you have to drop the whole transaxle to do it.....so it take some time

The burnt fluid is more concerning...especially in such a short distance.....since the Mercedes trans is VERY strong and lasts about forever with minimal upkeep...the big ones are:

1: Fluid full
2: Cool fluid
3: 60k filter-fluid changes

Here is a quick story...my father in law had a BMW 325 with automatic...ran great for a long time...at around 170k the trans started to slip....so he paid a "good" local shop almost $3k to rebuild it.....ran great when he got it back....then a month later the trans blew.....why?....they didn't flush the cooler lines and one was blocked. which overheated and blew the NEW trans!!!

IcemanG17

also I do have an extra 4 speed auto (2.20) with open diff that came out of my 84 Estate racer.....it does need a new pump seal, but runs fine other than that..... I can have the shop that rebuild my current trans look it over and replace the seal for cheap....I'd also sell it for a LOW price...Bummer is its expensive to ship...where are you located?

Imo000

Uhmmm that pic looks like the rear TT pinch bolt hole. If it is, the TT bearings shoud limit any ATF from getting throught there. Can you take a better pic? I have a feeling that's not ATF that you are smelling.

mj1pate

Hi Brian; PM sent, thanks

mj1pate

Hi Imre;

That seepage at the inspection hole is a little bit confusing. There is definitely drippage at the TT grate that looks a bit more aggressive. The fluid I drained from the trans pan was black and had a burnt odor.

dr bob

Michael--

Fluid flows back into the trans from the cooler circuit at the factory fill port, the funny-looking hydraulic quick-connect fitting that pokes through the banjo. I'm not under the car, but IIRC flow is from driver's side fitting to passenger side fitting. Matters not though, since you will want to pull both connections off and push the old fluid out with some LOW PRESSURE air, less than 15PSI or so max If you can do that, the cooler circuit is open and that isn't likely your problem.

The mysterious part of this is the idea that you have stinky black fluid but the trans drives/shifts fine. You really want to get that out before it varnishes the valves and servos. Do the cooler loop flush at the same time. The second fluid change in 100 miles might show a trace of leftover black, but it should just be a trace in the old fluid at that point. If it's more start to worry. Someplace in the middle of all this you need to fix the leak.

Landseer

What entity rebuild the hydraulic fluid lines?
Do the hoses have identification printed along their lengths? (could the liners be breaking down?)

Do you remember what brand of fluid is in the unit? ( there was a period of time around 85 when Porsche switched to a formulation that got black and very smelly. They even issued a tech brief on it cautioning against using the odor to signal trans issues. I found it in my 85. Clean from a residue standpoint, but incredibly yucky smell. Just curious if you are using something outside of current typical Mobil 1 or Valvoline ...)

Also, I've smelled burnt fluid a (Suburban after pulling a boat up a mountain) and its got a scorched odor attribute that is strong, but completely different than the really smelly stuff.

Mrmerlin

Chris didnt you post info about trans fluid changing color after it was installed?? IIRC there was Porsche document that made mention of the fluid color turning a different color after it had been installed.
I would also want to know about if the lines that were used for the hose rebuild were for hydraulic systems if they used another type of hose it could be disintegrating internally