transmission fluid smell at idle | Ford Explorer Forums - Serious Explorations

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transmission fluid smell at idle

Lamar Clark

New Member
January 14, 2018
Reaction score
City, State
Dalton, Ga
Year, Model & Trim Level
2013 Ruby Red Sport
I have a 2013 Explorer sport, and am getting a transmission fluid smell inside the cabin periodically when stopped. The smell started about 2 weeks ago during a snow. Me and the family was driving around looking at the scenery (was driving in snow mode), stopped to take some pictures and when we got back in the truck I noticed the smell. We drove it for about a week (in regular mode) and the smell was periodically still there. I changed the transmission fluid and the smell is still there. The truck drives fine, shifts fine so the only symptom is the smell. The truck has 81k miles on it and we bought it new so I know it has not been abused. Any help will be greatly appreciated.

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Positive it's trans fluid and not PTU fluid? The latter is fairly putrid.

What is PTU fluid? I looked the engine and trans over and the only sign of any leakage was on the plastic cover on the trans. It wasn't wet but did have a layer of fluid covered with road grime.

Welcome to the Forum Lamar.:wave:
Have you noticed any drip spots where you park? There are several threads on the PTU seal leaking but that usually results in an oily spot when the vehicle is parked.
I have asked for an update on the following thread; PTU leaks after 4wd engages


Thanks for the welcome peterk9. There is no leak spot in the garage where it always sits. After the tip from thefranchise713 (thanks for the tip BTW) I did some research and it appears the build date make our explorer fall into that category. I have did a quick check and it appears my explorer does have the "wobbly cap head" line. Without taking anything lose it appears the line is dry at the top. I will continue to research but any time savings tips would be greatly appreciated.

OK, from everything I have read regarding the smell I am experiencing at stop lights I believe it is from the PTU. I have looked under the Exp and there is a small amount of residue on the bottom of the PTU, but it is dry and looks like it has been for a while. My plan is to suction the old fluid out and put new in. My question now is what could I put in to help clean the sludge out (if there is any). Also since I am only getting a smell symptom do you think my PTU could be hurt or should I continue as planned? Thanks in advance for everyone's input.

Just a thought, but have you checked the vent hose connection at the the top of the PTU? I just replaced mine with 2 foot of fuel line (per the great write-ups on PTU fluid changes) and was amazed how easily the original vent hose came away from the nipple, it practically fell off as there was no clamp holding it in place on my 13 sport. Maybe yours has come loose letting the vapors/smell come straight out and into the cabin.

Also check that the vent hose hasn't puked out PTU fluid in the engine bay.

Andy.J, I have not checked the line but I will. Pardon all the questions, but does the smell not indicate the PTU getting hot? If it is just a fluid change and hew hose I would be very happy.

From what I read the fluid smells really bad when old, not sure if worse through overheating, but would assume so.

The vent hose looks really easy to change but is a complete b***h to change in my experience, I have still not changed my fluid as I simply could not get decent access to the drain bolt (which is 6mm hex on mine, not 8mm or 1/4" as I read)

Unless you have the right tools, including a good set of jacks and stands (preferably a lift) I would recommend paying a local trusted garage to do this, I consider myself fairly competent at doing these 'simpler' kind of things (changed spark plugs and tranny fluid already, etc..) but I am pulling my hair out with the PTU fluid change because of the tight location of the PTU on the sport. That being said I will be continuing this endeavor this weekend as I hate to be beat by a 'simple' fluid change.

Even if the smell is not a PTU problem, in a 2013 it's due a fluid change in my opinion, assuming your warranty has expired.