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Water in Automatic Transmission

XJMark

NAXJA Forum User
I have a question for a friend of mine. I know it's not a Jeep but he was wheeling with me and asked for my help. He's got a late 60's GMC suburban with 33's and around 10" lift (he was stuck REAL bad, I couldn't budge him, took a stinger steered front loader to get him out).

Background: After having some fun in a bunch of mud we were wheeling through some flat land that a small manmade lake had overflowed onto to clean off before hitting the road for home (only about 8" of water). Suddenly his truck nosedived into a deep hole, thankfully the motor didn't hydrolock but he ended up with water in his automatic transmission.

He drained it and a whole bunch of water came out then finally clean fluid drained out. What would be next to make sure everything is OK? Is there any product he should add to help flush it, or should he just do a few fill / flush cycles with fresh trans fluid? Any suggestions will be greatly appreciated.

For those wondering, yes, the motor oil was contaminated with water too, but that's a bit more straightforward than dealing with a transmission and has been taken care of (no more milkshake oil).

Thanks,

Mark
 
Nice trick. I've never run across this one personally, so this is a bit of a guess...

First and foremost, I'd make sure that there is NO remaining water in the box, because it could cause at least as much damage as water in your engine oil (but can be far more insidious, as you won't notice it as readily...)

If the oil comes out with a good consistency after a flushing (I'd get something with a strong ethanol base, as ethanol will chemically bind with water and makes it easier to get rid of. Ethanol/water boils off at about 73*C, IIRC from Organic Chem...) and run that as a flush. Make sure to go thru all the gear ranges to get the stuff everywhere, and extra ethanol will simply boil off without any problem (and it does not promote rust, plus it is less detergent/antagonistic than everything in ATF to begin with.)

If you are so inclined (I probably would be!) you may want to drop the valve body and give it a good seeing-to. It's time-consuming, but basically simple if you keep your head on straight and take a picture before you take things to bits. The manuals aren't always right for the placement of the check balls...

DISCLAIMER - These are guesses, based on the SWAG principle (Scientific Wild-Assed Guess.) I take no responsibility for your actions. Your mileage may vary. Offer void where prohibited. No guaranteed offered, express or implied.

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5-90
 
oh ya, i feel confident :D
 
1. Whatever you read here/do in garage = major potential for complete tranny destruction.
IMO, there is water in the torque converter that will be a bitch to get out without a complete power flush of the tranny.

2. Cost of major tranny service (fluid exchange, filter, adjust bands; that it probably needed anyway) by reputable tranny shop = priceless peace of mind.

-Rick
 
The auto tranny is about the only thing I haven´t managed to fill with water. But I guess the steps in dealing with it are about the same. It isn´t the water you have to worry about, so much as the sand and grit that go with it.
Auto tranny´s are funny, sometimes it´s best just to leave well enough alone. Flushing and cleaning probably dislodges as much crude as it gets rid of. Seen a lot of guys change the filter and have shifting problems, within a few days.
I´d drop the pan and spary out the bottom with brake cleaner. Replace the filter. It would probably be a good idea to take out the torque converter and dump it out. I´d run at least three loads of fluid through it and probably two filters. Make sure your vent is open and next time run an extension up high somewhere. If the end of the vent is made in an upside down U form and a piece of filter foam tied to the end, it really helps slow down water getting in. The little bit of moisture left in there, will evaporate off pretty quick (it gets really hot) and then hold your breath and see what messes up.
I´ve heard of power flushes for the auto tranny, but never tried one myself. Heard at least one horror story about a guy who had.
One technique I´ve used on my MOG, is to let it set for a couple of days, most of the moisture finds it´s way to the bottom.
Like the man said, you´ve got a good chance of a junk tranny. Compare the cost of the shop, against the price of a rebuild. Figure out if your willing to take a chance for the difference. My experience with tranny service, is you have about a 40% chance of coming out of it better than when you started. I´ve put in six rebuilds in the last year. One was a return (junk), two didn´t shift right, one required some special parts from the return tranny (wrong year), one had stripped bolt holes and the last one worked well. From three different rebuilders. Auto tranny´s are sensitive to dirt.
The TH350/TH400 are pretty hard to mess up, I´ve got one thats been in a tow truck for 30 some years.
 
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Thanks for the info so far everyone, I'll pass it along. If anyone can think of anything else or has anything to add I'll keep checking and give my friend the updates. At least we have something to work with now as far as suggestions. Thanks again. :)

Mark
 
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