[john_wick]

As some of you may know, BMW lists these fluids as "lifetime" and not needing change unless there is an underlying problem. For anyone looking to keep their X a long time, have any of you DIY changed these fluids?

I plan on doing it sometime this year around 30k. Can't find any guides on this model but hoping its a simple drain/fill.

[GCR]

Yes, I did both differentials and the transfer case at 25k miles. Glad I did, as the front diff fluid was very dark. Only reason I can think of is elevated operating temp due to very little airflow and proximity to the oil pan. Plan on doing it every 25k, and the trans at 50k intervals.

[Brendon]

Originally Posted by GCR

Yes, I did both differentials and the transfer case at 25k miles. Glad I did, as the front diff fluid was very dark. Only reason I can think of is elevated operating temp due to very little airflow and proximity to the oil pan. Plan on doing it every 25k, and the trans at 50k intervals.

Hard to believe that the fluid would be so dark after only 25k. It's a sealed design, correct? Definitely going to put this one on my radar for earlier than anticipated.

[GCR]

Originally Posted by Brendon

Hard to believe that the fluid would be so dark after only 25k. It's a sealed design, correct? Definitely going to put this one on my radar for earlier than anticipated.

The front differential, at least on the '19 6 cylinder has both a drain and a fill plug.

[john_wick]

Originally Posted by GCR

The front differential, at least on the '19 6 cylinder has both a drain and a fill plug.

Was it straightforward drain and fill? Or was there any surprises or anything to know going into it?

[GCR]

Originally Posted by john_wick

Was it straightforward drain and fill? Or was there any surprises or anything to know going into it?

Straight drain and fill. I used BMW fluid from the Dealer.

[ivinioX7]

Originally Posted by john_wick

Was it straightforward drain and fill? Or was there any surprises or anything to know going into it?

I just took my X7 in for an inspection with 37k miles on it. It turns out my car needs a new rear differential. The vehicle is in the shop waiting for the part to come in. I'm planning on replacing the fluid in the front differential before it's too late. I'm also planning on replacing the oil fluid in my TC this summer, and here is the right product for the X7s if you look for it.

https://www.ecstuning.com/b-genuine-...r/83222409710/

[lake x7]

What are the symptoms of a differential problem? I had the transfer case replaced recently at 43,000 miles. Since then I have felt, on two occasions, a sliding grinding sound and feeling, just momentary leaving a stop light. This is a 2020.

[john_wick]

Originally Posted by lake x7

What are the symptoms of a differential problem? I had the transfer case replaced recently at 43,000 miles. Since then I have felt, on two occasions, a sliding grinding sound and feeling, just momentary leaving a stop light. This is a 2020.

I believe I read you can test this by trying a slow speed turn in say a parking lot and if the drivetrain shudders/binds you have an issue.

[itiongo]

My 2020 M50i is at 60k miles with this issue. I've had this issue for about a month. Just FYI for anyone who has CPO, the fluid drain and refill is not covered under CPO, however the transfer case replacement is. Since the fluid drain and refill is not covered under CPO, the diagnosis is also not covered. So it's almost $700 for this service.

My M50i is currently being driven by the technician to achieve the 125 miles. I'm hoping it's the transfer case. I'd hate for my CPO to end later this year, and have this issue return, and transfer case needs replacement.

[mitch57]

Is there any consensus on whether the transfer case issue is more prevalent in the 50i vs the 40i? I have a 2020 40i with 56K miles and don't have this issue so far. Knock on wood.

I do have an extended warranty that covers the transfer case if it fails. I plan on keeping the vehicle and some say you should change out the transfer case fluid every 50K or so if you plan on keeping it for the long haul.