Tramny Fluid in Oil

Asked by Dec 29, 2016 at 06:36 PM about the 2003 Chevrolet S-10 4 Dr LS 4WD Crew Cab SB

Question type: Maintenance & Repair

I have a 2003 ZR5 4X4 S10.Just recently installed
new aluminum radiator, electric fans, and auxiliary
coolers for tranny and oil. All hoses are hooked up
right, trust me I'm not an idiot. I've been losing
tranny fluid and my oil is going up. Putting two an
two together I'm leaking fluid into my oil. The
mystery is how? I've tried eliminating all
possibilities. Anyone has info, besides the whole I
hooked up the wrong hoses, I'm not dumb, please
help.

5 Answers

79,115

Well then what is different? The new radiator, correct? Is it possible there are some leaks in the oil cooling tanks? May need to get tested?

8,475

The only other explanation is a hole in the cooler. Since transmission has higher pressure, it leaks in the oil cooling chamber

60,745

...or something hooked up so that the fluids mix.

109,845

There were a few of these that has an oil cooler that ran coolant though it, thet were located back above the oil filter assembly and had coolant lines in and out, that might be your problem, if you have one. Is the replacement radiator just for the engine coolant or does it also have fittings for a transmission cooler inside? If it does don't use them, run the tranny lines right to the auxiliary cooler.

20,715

If the oil cooler and trans cooler on the radiator are on 2 different sides then it's not possible for them tk do this. Most coolers in radiators are just tanks that sit in coolant. Now coolant contamination is possible but there is no where naturally that transmission fluid can get into your oil. And I've never seen coolant ran to the oil filter adapter, that is however where the oil cooler lines are that flow oil to and from the oil cooler in the radiator, certainly not coolant.

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