Dexron stink after GM tranny service

[Mless5]

So this is the second time this happens after a fluid/filter/gasket change on e46. Under certain conditions I would get dexron stink through air vents. No, there are no leaks in PS nor transmission, no it is not a leaking VCG, yes, I followed refilling procedure, no I did not get on floor mats. What's the deal, is there a vent up top that it could be coming out of? Kind of wishing I never went there.

Thanks.

[scooper]

You probably missed some spots. Diff fluid stinks way more..

[Mless5]

Missed some spots when I was cleaning up you mean?

[Eaglesail]

You described very well your situation observing possible reasons. I don't believe a few 'spots' either. If I were you, pull the second underbody plastic pan off (I know that is a drag) and look for ATF drippage in the pan under the transmission....Or look for leakage connecting radiator etc... I have no answer for you, but you need to investigate this more.....

[dhurley34]

I had this exact situation happen to me right after a drain/filter/refill on a A5S390R. Trans shifted fine, no smoke or leakage, no fluid on the exhaust, yet I got an ATF smell through vents only when coming to a stop after driving for a few minutes. I found it was a mixture of two things. First of which, the trans was about 1/2 a quart underfilled despite using the prescribed refill procedure (pan temp is VERY critical and not all trans fluids have the same expansion rate) which I believe caused a bit of cavitation inside the case and blew the excess vapor out of the top of the trans via the vent tube.

The second thing is that certain transmission fluids have additives that naturally "burn off" and smell for the first couple of hundred/thousand miles of use by design. The difference is that our vent tube is right below a poorly sealed HVAC system which blows it in through the vents. Most other vehicles have the vent tube far away from the HVAC so you never smell it.

I would double check your fill @80-90 degrees with a IR thermometer. If thats fine, then allow the smell to simply burn off. Doing these two things solved it for me.

[Eaglesail]

Yea, the multi-speed auto transmissions of today's world, including ZF, General Motors, are, and have been, critical for exact measure...and based on temperature when measured for fill!

I miss the days when you pulled a transmission dip-stick....Simple worked ok...but I understand advanced auto transmissions of today, yet in spite, I still love a standard!

[Mless5]

Guys, thank you for the ideas, I will definitely try your suggestions and will report back.

[Mless5]

Added 1/2 cup of Dexron, change the fill plug, but still getting smell through the vents

[dhurley34]

If there are no leaks, I'm fairly certain it will burn off. It may take 1000 miles, but it will.

[Mless5]

Thanks, let's hope for that. The smell is less than before, but still is there.