So, any luck to refill it? I now have the exactly same problem. desperately need help. Was it at least reachable after removing the wheel well?

I had no issues reaching my fill plug from the left wheel well.
I also purchased the oil from my local BMW Dealer.

Not that you will really notice any difference with Redline products, but they do make great products and I fell just 1 less thing you have to worry about. I use them mostly in my bikes and do notice the difference in them, plus the one I like the best of my tranny fluid, looks like pepto, pink in color and very easy to tell if I ever get a tranny leak. :)

Harry

Front Differential Fluid Flush
 

Changed my rear today. As always rear diff fluid change is easy.

Tried to do the front and while I could reach the fill plug with an extension on my wrench, the metal lines prevented me from inserting the hex head into the female hex fill plug. Next up I have bought a longer hex tool from amazon and will report back. I'm thinking this may work better to get past the lines which I believe are the dynamic drive pressure lines. Looks like E70s without dynamic drive would have no issue removing this plug.
http://tapatalk.imageshack.com/v2/14...ca21ef2568.jpg

Would some one please post pictures of drainage and fill plugs locations? If possible, step by step to complete this task? Thank you in advance.

Front Differential Fluid Flush
 

Completed the front differential fluid change yesterday using the long hex bit socket. It was still a pita with the metal lines on the way. First I tried to bend them slightly out if the way but abandoned that in fear of damaging them as there is not much leverage to bend them from underneath in that area. I kept trying from the wheel well side and almost gave up but one final chance after connecting another medium long socket extension I was able to force the long hex bit in. I could see the metal line moving slightly aside as I was pressing in to fit the hex bit. An extra long hex bit socket would work and reach much easier.

Proceeded with the drain from underneath then the after putting on a new drain plug and torquing to spec I filled up the differential with Redline fluid using a fluid transfer pump that fits standard quart bottles. After the fluid starts to flow out of the fill hole I knew I had enough in there. Then now back to putting on a new fill plug. Starting the thread was not going to happen easily as there is no space for fingers down there and the hex bit cannot carry the fill plug to start the threads past those metal lines. I ended up attaching the fill plug to a magnetic telescoping pick up tool and reaching in through the wheel well to start the thread and screw on as far as I could. Then used the long hex bit to tighten and torque it to 44ft/lbs. Took me a little while to insert the hex bit to the bolt just like the first time. Next time I would use an extra long hex bit socket as it would clear through both the rubber boot and the metal lines as shown in the pic on post #12. Patience is required for this DIY. Sorry I didn't take any pics.

Is it the same exact fluid for both front and rear differential?
How much volumn do we need to flush front and rear differential fluid? 1L for front and 1L for rear?

Thanks

Same fluid. I used Redline 75W90 gear oil. IIRC about 1.5quarts for rear and less than 1quarts for front.


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About to tackle this project this weekend. Two questions, do I need all new drain and fill plugs for the front and rear differential? And the Redline gear fluid, how come it has two part numbers on amazon??

Thanks, Sam

I recommend new drain and fill plugs for both front and rear drain and fill plugs because they will have new sealing rings built in. They are the same part number front and back for the each two plugs.

I used Redline 75W90 part number 57904 from amazon. The other is for non-limited slip differentials. Someone else can chime in on the specifics and details between the two systems but the former is what has always been recommended for non-M cars and have always worked great for me.