Synthetic Transmission Fluid leak - PeachParts Mercedes-Benz Forum

lee polowczuk · #1 09-18-2009, 08:21 AM

Well... i thought this was more of an urban myth.

Just bought a 95 E320. Very slight transmission drip. Very slight.

Of course I want to baseline all fluids, so I drain the torque converter, and pan.

Put in Mobil 1. Within 30 miles of driving, torque converter is leaking. I assume it's the front transmission seal.

I guess this is a grand to repair.

epowers777 · #2 09-18-2009, 02:54 PM

did you put in a new seal on ur torque converter? Its a few cents at auto hauz you shouldnt re use those.

gmercoleza · #3 09-18-2009, 03:08 PM

Ditto on the crush washers - you should not reuse them. Stop the car and see if it's leaking from the plug on the torque converter.

lee polowczuk · #4 09-18-2009, 03:16 PM

yes... i went to the dealer to get the correct crush washers.... i will get under the car again and turn the engine to inspect the torque converter bolt...

the transmission pan bolt is not leaking....

i'll report back tomorrow..

Yak · #5 09-18-2009, 04:16 PM

I've got similar symptoms with different fluid and a different tranny. I bought an '83 300CD and let it sit undriven while I worked on the suspension. There were no leaks while it was sitting - maybe the fluid the was low, or maybe it was just happy with the old fluid.

I changed the tranny filter and fluid (Castrol Dexron III) and now I get a good amount dripping from the grid forward of the pan. I think it is coming from the front shaft seal. I've read that the older seals are prone to settling and shrinking if the car is left to sit for a few weeks, so I 'hope' it'll swell shut with increased use and the new fluid. If not, then I'm probably looking at having it rebuilt anyway since I think it's original with no rebuild and 280,000 miles.

If the seals do shrink, the leaks in your "new" car may have more to do with how long it was sitting prior to your purchase than a simple change in fluid.

babymog · #6 09-18-2009, 07:59 PM

If the transmission had some stop-leak or trans tune-up fluid in it (strong solvents to make the seals swell), and you drained that fluid / changed it without adding a similar solvent to swell the seals, it will leak.

Fairly common when one buys a car and changes the ATF, that's probably one of the reasons the PO was selling it.

lee polowczuk · #7 10-02-2009, 01:31 PM

I just wanted to update everyone on my leak.

I had to succumb to a shop which is rare. Anyway.... they chastised me for using a screwdriver to turn the torque converter. I have done that many times and thought i was careful.

That said they think that can cause you to break a seal. Still didn't make sense to me.

In the end the seals and o-rings were in good shape. But the bushing for the front pump was shot causing the leak. They also replaced a front flex disc. It was cracked but i had no vibration. They replaced the pump even though he said it is possible to just replace the bushing... he said it just takes a long time to do.

Anyway, i picked the factory trained mechanics brain on fluids.

He strongly recommended sticking with Dexron III. He just said that was factory fill and he has never had problems.

He also uses Rotella 15w-40 over anything else for the 124's and most other older benzes. He cautioned about other oils not having the necessary additives need to protect cam wear. Don't get me wrong..he said in the newer mb's he does use synthetic

btw....he drives an early 80's european 126... said the car has more than 600k on it. Cosmetically it was crap...but he said nothing has the torque that his car has.

just my .02.

I hate to spend money at the indy but this was money worth spent, i believe

I can't drop a tranny.

gmercoleza · #8 10-02-2009, 02:06 PM

how much $$$ did it run you?

lee polowczuk · #9 10-02-2009, 02:14 PM

front pump, flex disc , seals , fluid

1540 with tax. labor was 8.7 hours... at 95 dollars an hour...

it took them every bit of 8.7 or so it seemed.

babymog · #10 10-02-2009, 10:15 PM

"He strongly recommended sticking with Dexron III."

Dexron III is any fluid that meets the minimum requirements of Dexron III (GM), which includes all synthetic ATFs that I know of, and roughly half of the non-synthetic fluids.

If it's ATF, it meets Dexron III (or later) or it meets Ford's standard.

Other than being better suited to operation in a cold winter climate, and better thermal transmissivity (for towing or heavy-duty), I haven't had synthetic ATF cure nor cause any problems, it's just ATF in a car.

As far as Rotella 15W-40 in a gas Mercedes, everyone has their favorite flavor, it isn't any better than the non-synthetic premium Mobil/Valvoline/et al oils. It also isn't a recommended viscosity for your car.