Can ATF leak into the cooling system on a 2003 Accord V6

Tiny
NAVYDOC8425
  • 2003 HONDA ACCORD
  • 16,000 MILES

I have a 2003 accord that has brown colored coolant, and having tranny slipping. Transmission was very low on fluid. Replaced fluid. Flushed out cooling system. Car drove very well for about 70 miles. No transmission slipping. Then started slipping again. Looked into engine compartment and more brown being forced out of the coolant resevore and tranny was very low on fluid again.

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Wednesday, November 16th, 2011 AT 5:38 AM

4 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
  • 68,495 POSTS

The transmission cooler runs through the radiator. There must be an internal leak there. This needs to be repaired ASAP because it will take out the trans.

Check that for me. If I am correct, the radiator will need replaced.

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Wednesday, November 16th, 2011 AT 5:42 AM
Tiny
KHLOW2008
  • EXPERT
  • 42,119 POSTS

This model does not have hoses to the radiator. There is a cooler/warmer that is attached to top of transmission. That unit should be faulty and requires replacement.

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Wednesday, November 16th, 2011 AT 11:44 AM
Tiny
NOELNOCHIM
  • MEMBER

I'm having the same problem with ATF tan sludge in coolant. The coolant hoses were all replaced and the system holds pressure. The car holds temp for a while then overheats and spews tan colored fluid to the reservoir. I think that the ATF pressure is much higher than the coolant pressure (13 psi -ish) so the ATF leaks into the cooling system. Do you know if there is a history of leaks in the ATF warmer. There are a couple of "o"rings between the warmer case and the mounting to the tranny. And ATF could leak into the coolant there. Whatever causing the leak, the problem doesn't appear until some miles are put on the car. The last occurrence occurred 6 miles after the engine first came up to temp and the thermostat opened. Thanx for taking the time to respond. Noel nochim

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Wednesday, February 22nd, 2017 AT 11:57 AM
Tiny
2CARPROS KEN
  • ADMIN
  • 12,211 POSTS

Hey Noel,

I would bypass the warmer/cooler and drive the car for a short time to see if transmission fluid is leaking from the warmer/cooler. Use a short piece of tube as the splice.

Please run this test and get back to us so we can continue helping you.

Best, Ken

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Friday, February 24th, 2017 AT 2:12 PM

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