Yikes, water in transmission! - PeachParts Mercedes-Benz Forum

pselaphid · #1 08-12-2009, 06:41 PM

So, I went to drain the fluids from my carcass in prep for pulling the engine and transmission. Oil was normal. Moved to tranny, first quart or maybe more of fluid was CLEAR, it was water! Car has been sitting in my drive for over a year. Trans check/fill tube has been covered as normal, trans cooler lines connected until recently and they were pointed down into containers to catch drips. Nothing undone on it at all, and it ran great/shifted fine before the wreck, in fact had been rebuilt a couple years prior and I never even opened it between then and now. How is this possible? Would have been an extremely odd act of vandalism given other things available to mess up, but I'm mystified. Can't imagine that much water just from condensation.

I'll pull the pan and check for obvious rust and other damage when I get it out, but any other advice is welcome. I had envisioned this tranny as a replacement for my daily driver if/when it gives out (150K, no rebuild). Now I'm not so sure.

I did a quick search and nothing obviously similar came up.

automch · #2 08-12-2009, 06:49 PM

Typically Automatic transmissions use water based glue to hold the friction material to the steel backing of the clutch plates. I have rebuilt many that had coolers fail ( Domestic and foreign) and get coolant in the trans. They always say, "but that was a couple months ago, we changed the fluid when we replaced the radiator and it was alright until now".

When you open up the trans all the friction material will be cleaned off. Save yourself the trouble of removing it twice and rebuild it or have it rebuilt before swapping it in. They are not really that hard to rebuild. You probably will need a valve body after having that much water in it. Good Luck!

JimFreeh · #3 08-12-2009, 06:56 PM

Was the radiator damaged?

The trans oil/coolant heat exchanger could introduce coolant into the trans if breached.

Jim

pselaphid · #4 08-12-2009, 07:02 PM

I thought of the possibility of a failed cooler, but the radiator had green coolant in it (propylene glycol based). Wouldn't the contaminant have been green? The coolant from the radiator didn't seem contaminated either when I drained it a few weeks ago. Would've made more sense to me, but it was definitely water clear. Thanks for the warning about the glue, and now I'll pressure test the radiator before I reuse it. I'm fairly certain I won't be sticking that tranny in another car now without addressing likely problems you brought up.

Edit, must confess I didn't taste it.

pselaphid · #5 08-12-2009, 07:22 PM

I'll go recover the waterish looking fluid into a clear container and have a close look at it and report back (I'll take a picture!). I agree that it almost has to be antifreeze.

Cr from Texas · #6 08-12-2009, 07:33 PM

This is a crazy off the wall thought:
On some of our cars, the AC evaporator drains the condensed water onto the top of the transmission. There should not be a pathway in but would it be possible due to a missing bolt, cracked case, etc?

Remember, my thoughts are not worth anything more than you paid!

pawoSD · #7 08-12-2009, 08:17 PM

I'm always paranoid about the trans heat exchanger.....someday I might put on a separate one to cure my paranoia.

barry123400 · #8 08-12-2009, 08:33 PM

Is there any possibility the transmission was submerged at some time? there usually is a transmission vent on the top. Minor flood car?

pselaphid · #9 08-12-2009, 08:48 PM

Nope, car lived in San Antonio prior to me getting it, and as mentioned had a trans rebuild a few years ago. It lived a pretty normal life before getting hit May 08. I like the off-the-wall AC drain into the vent tube idea, or rain somehow getting into the vent tube while its been sitting out. Can someone tell me exactly where the vent is and I'll go out and see if its open on top. I assume normally it should have some sort of cap on it.

Cr from Texas · #10 08-12-2009, 09:04 PM

There was major flooding in San Antonio in the last few years.

pselaphid · #11 08-12-2009, 09:09 PM

Trans was rebuilt in Baton Rouge. No, the car was not flooded.

babymog · #12 08-12-2009, 09:11 PM

I'm guessing it was hit in the front?

If the transmission cooler failed during the crash, and there was still pressure in the radiator, water would go into the transmission.

If only through the return line, it might have safely laid beneath the ATF and the transmssion is fine.

pselaphid · #13 08-12-2009, 09:31 PM

Wrong guess, but close and you might be right. It was hit on the driver fender behind the bumper. Bent the inner body slightly, door post and door, crammed in the upper control arm. Very low speed. The guy was looking straight at me the whole time he slowly turned into me, the female passenger actually saw it coming, but too late. So, there wasn't a tremendous impact, just a sickening crunchy sound.

Update, I recovered some of the fluid, but I think the gunk that was already in the container has discolored it from the pristine stuff I watched come out. Still doesn't look like coolant...but dirtier than what I remembered. Tomorrow I will do some testing on the stove to see if it boils at water temp or 50/50 coolant mix. I'm guessing 212F. I'll pressurize the radiator with my garden hose and check if it leaks. Would be good to know if this is something else to worry about or just some wierd fluke. In the mean while, thanks and chime in with any other ordinary or wild notions.

Edit, maybe I won't use the garden hose, that might be too much.

pselaphid · #14 08-13-2009, 12:07 PM

I did a little test to determine whether the stuff that I drained from my tranny was water or antifreeze from a blown radiator. First, I boiled some water to determine if my little kitchen thermometer was registering correctly. Rolling boil at 212 and stabilized there. Then I boiled a 50/50 mix of propylene glycol/water, same stuff that was in the radiator. Rolling boil slightly above 220 and stabilized at 220. Then I boiled the stuff that came out of my transmission, rolling boil at 212.

So, I had water in my transmission and I have no idea how it got there. I didn't put it there, I don't think anyone else would have, and it didn't get submerged. I'm going to look for possible entry points on top of it now.

rrgrassi · #15 08-13-2009, 04:50 PM

Was the hood open while the car was parked?

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode