I have searched and found a well documented DIY with pictures on how to change the rear diff fluid. However, on my 09 6MT 535i, the rear diff only has one plug. I assume I can just take out the plug and suction out the old fluid? In other words, the diff didn't get filled at the factory above the plug, leaving me with a problem at refill time?

Thanks for your help.

 

Correct - suction out and refill.

If a problem did develop that necessitated disassembly of the housing then after reassembly the differential must be field fillable, so the level is not above the filler hole.

 

Do you mind posting the link to that DIY?

 

https://5series.net/forums/diy-do-yo...-change-88120/

Hope this works.

 

Hey thanks for that. I have owned my 545i for almost 6 years and am now catching up on the DIY stuff now that my car is hitting 67k miles. Not too shabby for an 8 year old car.

 

That of course makes perfect sense, and would be the logical result. Glad you confirmed if for me though. Thanks

 

what mileage change? i have an '08 that i'll be changing soon, and now has 425xx miles.

 

Opinions vary greatly, from every 50K miles to lifetime.

Based on the expense and ease of changing it, I would do it every 50K miles. I did mine at 80K miles (I purchased my 545i at 75K miles) and it looked very dark, but I did not have it lab tested so I can't address whether the fluid was still doing the job or not.

Again, cheap and easy to do so why not keep it fresh. I'll do mine again in another 50K miles.

 

51k

 

Our '06 E61's rear diff also has just the one plug. My son and I did the "suction and refill" late last year.

HTH,
Jim / crewzer