Hola Mini Experts/Owners,

Car: 97k miles, 2014 Mini Cooper S Hardtop Manual

I recently did a transmission flush myself and as I was filling it up I noted how g-d damn awful the Valvoline Trans Fluid smelled (actually irritated my nose and eyes too). It smelled like classic farty sulfur smell and harsh chemicals, essentially.

Anyhow, when doing the flush I filled with fresh transmission fluid until it began pouring a bit out of the fill hole and then bolted it shut. Car was on a pretty steep tilt though as I had only jacked up the front to do the flush. Does tilting the car back like that cause one to overfill/underfill the trans case? Well, either way, after spirited driving I swear that the damn trans fluid stench begins coming through my AC vents. Otherwise, it shifts real nice now and actually quieted down the transmission a bit.

Any ideas on the smell though?? Is it a symptom of overfilling/underfilling? Does it mean the transmission fluid was spoiled or not good or something?


This is what I used.

 

Update: (hope this helps others out!)

I did a bunch of research and turns out people on BMW boards have been posting about this since 2009 (earliest post I found). It seems the fluid just stinks for a while when freshly changed. Most people reported it went away between 1-4 weeks. Im on week 1, so I'll post later down the line to confirm. Still interested in your thoughts!