2016 F53 26K lbs 5 speed trans. overflow or what?

[Americanrascal]

Today while crawling around under my rig I noticed oily residue on top of the transmission. Nothing too significant, but probably about 1/4 cup was there spread over the top of the transmission.

It was not fresh and had obviously been there for quite while. I assumed it was transmission fluid as there was no evidence of any leakage from around the engine. It appeared to emanate from a small rubber like 1/4 inch pipe- about 2 1/2 inches tall- that was atop the transmission with some sort of cap on the device . I noticed no seals in the vicinity of this area on top of the transmission-- only the pipe like structure at the top. It was evident that nothing recently had been deposited at this site.

I then checked the transmission fluid level. It was at the bottom of the safe zone after running the temp up to operating levels and putting the rig in gear. I added about 2 cups and raised the level into the safe zone on the dipstick.

Any ideas what this small vertical pipe that sticks up is and why a deposit of what I suspect is transmission fluid from some sort of overflow device? Is this abnormal? I have about 27,000 miles on the chassis.

[Chmielowiec]

The rubber tube is a breather and the cap on the end is a vent cap to keep debris from entering the trans could be that when the trans oil warms up and expands the trans is in a overfull condition and oil pukes out the breather did you clean the top of the trans if not clean it and take a trip and check it if you have oil on top again you may have to run it lower than full on the dipstick to keep oil from puking out play with it good luck

[Americanrascal]

Originally Posted by Chmielowiec

The rubber tube is a breather and the cap on the end is a vent cap to keep debris from entering the trans could be that when the trans oil warms up and expands the trans is in a overfull condition and oil pukes out the breather did you clean the top of the trans if not clean it and take a trip and check it if you have oil on top again you may have to run it lower than full on the dipstick to keep oil from puking out play with it good luck

Appreciate the recommendation. I'm watching it exactly as you note. It was a very small quantity initially, never going down the sides but a small pool (maybe 1/4 cup at the most-- and old) initially noted on top in very small puddle around cooling fins of tranny case.

Joe