transmission fluid in coolant

I've noticed my overflow tank for the coolant on my 98 Dodge Grand Caravan appear dirty recently and thought that was odd since I had the entire system flushed 2 years ago. I decided to drain and flush the coolant system when I discovered what appears to be tranny fluid in the drained coolant. Now I've read past threads about this issue causing problems with getting the coolant mixed back in with the transmission and ruining it. Since I'm going on vacation next week, I ran it immediatly down to my mechanic for a new radiator. I also changed the transmission fluid last spring and have had no issues (knock on wood). Question is, do you think I did any damage to the transmission? Fluid looks great, clear with a bit of pink on it. Man I don't want any issues when I'm on vacation.

thanks,

MN Walleye

Those transmissions were known to be weak from the start so to say that the problem would be caused by contaminated fluid or just from their defects are hard to say. The question is how long did you drive it like that? Also did you flush the coolant out of the motor before you refilled the radiator? Remember when you drain the coolant you need to flush the motor because residue may remain in the water jacket. I normally don't use snake oils, but the lucas transmission lubricant has helped out in a pinch many times.I might suggest that you put that in the transmission for piece of mind.

I agree with tri-power about flushing the coolant from the engine and since you got a new radiator I would expect the shop did that for you but I would check. The pressure in the coolant system is far lower than that of the transmission. I doubt very seriously that you got any coolant in the transmission although it is possible. Before going on vacation I would have the fluid and filter changed in the transmission. This will be good for the transmission and if there is any coolant in the transmission it should drain it out since water is heavier than the fluid.

Thanks for the response, yes I did request to my mechanic flush the cooling system. I also requested if any transmission fluid needs to be added since he'll probably loose some out of the cooler to only use ATF+3 and never dextron. He fully understands. Not sure how long this condition has been going on but I watch these fluid levels like a hawk. I even have a small sharpy mark exactly where the level should be when cold to give me a quick glance to see if this changes which could indicate head gasket issues.

My mechanic just called and said the van is ready, didn't need to add any transmission fluid, he said the leak was so small that it only got a small tranny fluid in the radiator which ended up in the top. He also said the tranny fluid is so clean like I just added it.

Thanks again for the help,

MN Walleye

Needs a new radatior,the transmission cooler is split.I replaced a transmission in a 2001 Dodge Neon that was that way.But the transmission fluid loooked like Pepto Bismo.The radatior had to be replaced also,the transmission cooler split.

mine just did the same thing mixed tranny fluid and antifreeze and had everything flushed but still ended up having to rebuild my tranny because the anti freeze messed the bands inside the tranny $1800 to have the tranny rebuilt. Hope the got it all out of the tranny when they fluhed it. Good luck FrankC

I hope they replaced the radiator too or you will have to repair the tranny again. If you did and they rebuilt the tranny you should have no further problems.

I hope they replaced the radiator too or you will have to repair the tranny again. If you did and they rebuilt the tranny you should have no further problems.


Thanks GTP, got back from my North and South Dakota trip with no problems what's so ever. I did not flush the transmission fluid as I think the leak had just started. My mechanic says the transmission has a few more lbs of pressure then the cooling system so it tends to flow one way when the leak is small but if it's not taken care of right away, the fluids eventually mix causing all kinds of problems. Still crossing my fingers and watching those levels.

This forum is extremely valuable in that even if you don't wrench your own vehicle, it gives you important information to be aware of.

Thanks again,

MN Walleye

Yes i replaced the radiator and also had them put in a tranny cooler and so if the radiator blows up again then it wont effect the tranny in other words the tranny lines are no longer connected to the radiator.

Wise decision. The tranny will probably last longer due to increased cooling too!