Help... Rear diff leaking
Hello everyone... I'm wondering if anyone knows why or where my diff is still leaking from?
A little history... I changed the rear diff oil back in March, I used Redline oils and I believe it was 75W90. Prior to changing the rear diff oil, there appeared to be no leaking issues. I had the car backed up on ramps when I did the change and I sucked the oil out, and refiled it with my transfer pump, so I know being that the car was on ramps, I probably overfilled the rear diff a little because it wasn't perfectly level. So after a about months time, I noticed the rear diff was dripping on my garage floor. So I figured it was no big deal, its probably just leaking out a vent or something since its probably overfilled a little. At least thats what I'm used to with my Jeeps... But, now its been about 7 months and 7k miles and its still leaking, especially when I run it hard. So yesterday I backed it up on the ramps and cleaned everything up with carb cleaner, because there was no way of telling where it was leaking from with all the oil and grime all over the rear diff, crossmember and exhaust. I then took it for a normal 15 mile round trip drive and put it on the ramps again and no signs of it leaking anywhere... Then today I figured I would run her hard, so during a 10 mile drive I did 3 hard brake boosting launches running it up to 3rd gear, and I also did some sharp turns from a stop, jumping on it hard to break traction, because if I do it hard enough I can even get my xi to 4 wheel drift! So after all that, I put it on the ramps again, and sure enough the diff oil was running down the back cover and dripping on the garage floor. The diff itself was barely even warm, and from what I can tell its leaking from what appears to be a little vent hole, or maybe its a set screw? I cant really tell while laying on my back with a flashlight... LOL
Here is a picture I found from FBIS to show what I'm talking about... its leaking from that little black hole, or is it set screw? Does anyone have any ideas what that is, or why it would still be leaking 7 months later?
2008 BMW 335xi Coupe... 11.988 @ 114.80 w/1.59 60'
19" Avant Garde M310 Wheels w/ 235/35 & 275/30 G-Max AS-03 tires ~ KW V1 Coilovers
BMS JB4 G5 ~ BMS WW meth kit ~ BMS OCC ~ ER Charge Pipe w/Tial BOV ~ Stett CAI ~ Helix FMIC ~ AR Design DP
Aero Front Lip ~ Black Kidney Grills ~ Painted Lowers ~ Painted Reflectors ~ Aluminum Pedals ~ BMS angle eyes ~ 35% tint