Changed MT fluid to Redline D4, now can smell D4 when driving?

NumericalIntegration · 02-03-2019, 11:43 AM

Hello all, as the title states, I changed my MT fluid to Redline D4 ATF since I've seen it recommended, and it's a bit thinner than MTL and a bit thicker than D6. Since then, when I hit it with WOT at med-high RPMs I can smell the D4 I just put in inside the car (06 325i, Gertrag GS6-17BG). I crawled under the car to check for leaks and checked the plugs. The fill and drain plugs have no leaks. The output shaft seal seems pretty dry. The selector shaft seal however has some fluid gathered near it (see attached picture). I thought I found my issue but when I got that fluid on my finger and smelled it it definitely didn't smell like ATF, it just smelled like some regular oil. The only thing I can think of is that it was either the original BMW fluid or the MTL I had in there before. So it's probably something I should replace but it doesn't seem to be where the D4 is coming from.

Today I was looking on RealOEM and I saw a ventilation valve on top of the transmission, what is this ventilation valve? Is it possible I overfilled the D4 and this valve is ventilating vapors from inside the overfilled transmission when under high load? Any input would be appreciated.

Efthreeoh · 02-03-2019, 01:29 PM

That is the shift shaft, not the vent cap. The fluid can leak from the shaft seal, but it is very little if it does; you'd never smell it from inside the cabin. Are you sure you just didn't get the new trans oil on the upholstery and that is what you are smelling? It's not possible to overfill the transmission if the car is level when you refill it. When the fluid starts to dribble out of the fill hole the trans is correctly filled.

NumericalIntegration · 02-03-2019, 02:13 PM

Quote:

Originally Posted by Efthreeoh

That is the shift shaft, not the vent cap. The fluid can leak from the shaft seal, but it is very little if it does; you'd never smell it from inside the cabin. Are you sure you just didn't get the new trans oil on the upholstery and that is what you are smelling? It's not possible to overfill the transmission if the car is level when you refill it. When the fluid starts to dribble out of the fill hole the trans is correctly filled.

I'm sure it isn't on any upholstery inside because I never smell it unless I'm accelerating quickly and even then it's not always. When I was doing the change I did make quite a mess putting the second bottle in so I guess it's possible I splashed some near the exhaust so it could be smelling when it gets hot?

I asked about overfilling because that's the only other explanation I can think of but I also am unfamiliar with how the vent works.

beermeister kink · 01-12-2021, 11:34 AM

I also can smell the red line d4 in the car after a manual transmission fluid change - did you ever figure this out? I'm thinking of changing it to a different fluid.

I had thought maybe I got some inside the cabin but I cleaned all of the leather and I still smell it when I initially get in. I know that's different from your issue but I'm hoping whatever solution you found would apply to me as well.

edycol · 01-26-2021, 04:17 PM

Quote:

Originally Posted by beermeister kink

I also can smell the red line d4 in the car after a manual transmission fluid change - did you ever figure this out? I'm thinking of changing it to a different fluid.

I had thought maybe I got some inside the cabin but I cleaned all of the leather and I still smell it when I initially get in. I know that's different from your issue but I'm hoping whatever solution you found would apply to me as well.

Redline products (performance series) has huge amount of Esters. Esters smell like hell.

02-03-2019, 11:43 AM	#1
NumericalIntegration New Member 3 Rep 17 Posts Drives: 2008 Z4 3.0si Join Date: May 2018 Location: Charlotte, NC iTrader: (0)	Changed MT fluid to Redline D4, now can smell D4 when driving? Hello all, as the title states, I changed my MT fluid to Redline D4 ATF since I've seen it recommended, and it's a bit thinner than MTL and a bit thicker than D6. Since then, when I hit it with WOT at med-high RPMs I can smell the D4 I just put in inside the car (06 325i, Gertrag GS6-17BG). I crawled under the car to check for leaks and checked the plugs. The fill and drain plugs have no leaks. The output shaft seal seems pretty dry. The selector shaft seal however has some fluid gathered near it (see attached picture). I thought I found my issue but when I got that fluid on my finger and smelled it it definitely didn't smell like ATF, it just smelled like some regular oil. The only thing I can think of is that it was either the original BMW fluid or the MTL I had in there before. So it's probably something I should replace but it doesn't seem to be where the D4 is coming from. Today I was looking on RealOEM and I saw a ventilation valve on top of the transmission, what is this ventilation valve? Is it possible I overfilled the D4 and this valve is ventilating vapors from inside the overfilled transmission when under high load? Any input would be appreciated. Attached Images
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02-03-2019, 01:29 PM	#2
Efthreeoh General 19915 Rep 19,257 Posts Drives: The E90 + Z4 Coupe & Z3 R'ster Join Date: May 2012 Location: Verginny iTrader: (0)	That is the shift shaft, not the vent cap. The fluid can leak from the shaft seal, but it is very little if it does; you'd never smell it from inside the cabin. Are you sure you just didn't get the new trans oil on the upholstery and that is what you are smelling? It's not possible to overfill the transmission if the car is level when you refill it. When the fluid starts to dribble out of the fill hole the trans is correctly filled. __________________ A manual transmission can be set to "comfort", "sport", and "track" modes simply by the technique and speed at which you shift it; it doesn't need "modes", modes are for manumatics that try to behave like a real 3-pedal manual transmission. If you can money-shift it, it's a manual transmission. "Yeah, but NO ONE puts an automatic trans shift knob on a manual transmission."
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01-12-2021, 11:34 AM	#4
beermeister kink Enlisted Member 25 Rep 35 Posts Drives: 2013 e93 m3 Join Date: Dec 2012 Location: Washington DC iTrader: (0)	I also can smell the red line d4 in the car after a manual transmission fluid change - did you ever figure this out? I'm thinking of changing it to a different fluid. I had thought maybe I got some inside the cabin but I cleaned all of the leather and I still smell it when I initially get in. I know that's different from your issue but I'm hoping whatever solution you found would apply to me as well.
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