[pw0n]

Getting ready to do my rear diff fluid change on my 435i RWD, part # 33107603748 (non-M Performance/non-LSD). Based off the part #, realoem lists Hypoid axle oil G1 (83222295532) for the fluid, but I ain't about to drop $150 on fluids when there are cheaper, equivalent alternatives.

Did some research and found many people recommending full synthetic 75W90. That said, I was just about ready to pull the trigger on the Red Line 57904 (75W90 GL-5) based off recommendations from multiple forum members.

However, came across this...
https://www.bimmerworld.com/About-Us...Oil/#rear-diff

It states for models produced after 07/2011, "G1 synthetic, 75W85 weight, GL-4 rated" should be used, which is clearly not the same as 75W90 (presumably).

I know this topic has been beaten to death, but I don't want to make any silly mistakes.

Couple of questions:
1) Which fluid should I get?
2) How much do I really need? I'm seeing differing responses - some are saying a little under a liter while others are saying a little over a quart (which could mean over 1L considering 1L is about 1.05qt), etc. Just want to ensure I don't get 2L/2qt when 1L/1qt suffices
3) I know BMW advises against mixing fluids, so if indeed I should be using 75W85 GL-4 (even 83222295532 is listed as 75W85), why do so many recommend 75W90 GL-5?

[KeelTiii]

Originally Posted by pw0n

Getting ready to do my rear diff fluid change on my 435i RWD, part # 33107603748 (non-M Performance/non-LSD). Based off the part #, realoem lists Hypoid axle oil G1 (83222295532) for the fluid, but I ain't about to drop $150 on fluids when there are cheaper, equivalent alternatives.

Did some research and found many people recommending full synthetic 75W90. That said, I was just about ready to pull the trigger on the Red Line 57904 (75W90 GL-5) based off recommendations from multiple forum members.

However, came across this...
https://www.bimmerworld.com/About-Us...Oil/#rear-diff

It states for models produced after 07/2011, "G1 synthetic, 75W85 weight, GL-4 rated" should be used, which is clearly not the same as 75W90 (presumably).

I know this topic has been beaten to death, but I don't want to make any silly mistakes.

Couple of questions:
1) Which fluid should I get?
2) How much do I really need? I'm seeing differing responses - some are saying a little under a liter while others are saying a little over a quart (which could mean over 1L considering 1L is about 1.05qt), etc. Just want to ensure I don't get 2L/2qt when 1L/1qt suffices
3) I know BMW advises against mixing fluids, so if indeed I should be using 75W85 GL-4 (even 83222295532 is listed as 75W85), why do so many recommend 75W90 GL-5?

With high heat, water contamination and oxidation some packages can "break down or wear out" the copper inhibitor that is why using a GL-5 where a GL-4 can be used maybe asking for trouble. (Source: BITOG)

I would get 3 of 500ml OEM fluid if I were you. It's not likely that you are going change diff. fluid every 6 months.

[johnung]

Originally Posted by pw0n

Getting ready to do my rear diff fluid change on my 435i RWD, part # 33107603748 (non-M Performance/non-LSD). Based off the part #, realoem lists Hypoid axle oil G1 (83222295532) for the fluid, but I ain't about to drop $150 on fluids when there are cheaper, equivalent alternatives.

Did some research and found many people recommending full synthetic 75W90. That said, I was just about ready to pull the trigger on the Red Line 57904 (75W90 GL-5) based off recommendations from multiple forum members.

However, came across this...
https://www.bimmerworld.com/About-Us...Oil/#rear-diff

It states for models produced after 07/2011, "G1 synthetic, 75W85 weight, GL-4 rated" should be used, which is clearly not the same as 75W90 (presumably).

I know this topic has been beaten to death, but I don't want to make any silly mistakes.

Couple of questions:
1) Which fluid should I get?
2) How much do I really need? I'm seeing differing responses - some are saying a little under a liter while others are saying a little over a quart (which could mean over 1L considering 1L is about 1.05qt), etc. Just want to ensure I don't get 2L/2qt when 1L/1qt suffices
3) I know BMW advises against mixing fluids, so if indeed I should be using 75W85 GL-4 (even 83222295532 is listed as 75W85), why do so many recommend 75W90 GL-5?

Mine took a one liter bottle. I've heard and read bad things about putting the wrong differential fluid in. I went to my dealer and talked to the experienced parts manager. He was able to shift through various old and new part numbers to determine exactly which was correct. Mine was <$50.

If the dealer price is a lot higher then take that exact part number to GetBMWParts, FCP Euro, etc. But buy that exact BMW part. Don't let anyone talk you into anything else

[ooshnoo]

I used LiquiMoly when I changed mine last month.

[pw0n]

Originally Posted by KeelTiii

With high heat, water contamination and oxidation some packages can "break down or wear out" the copper inhibitor that is why using a GL-5 where a GL-4 can be used maybe asking for trouble. (Source: BITOG)

I would get 3 of 500ml OEM fluid if I were you. It's not likely that you are going change diff. fluid every 6 months.

Originally Posted by johnung

Mine took a one liter bottle. I've heard and read bad things about putting the wrong differential fluid in. I went to my dealer and talked to the experienced parts manager. He was able to shift through various old and new part numbers to determine exactly which was correct. Mine was <$50.

If the dealer price is a lot higher then take that exact part number to GetBMWParts, FCP Euro, etc. But buy that exact BMW part. Don't let anyone talk you into anything else

You guys are absolutely right... I keep subconsciously treating this as an oil change or something. Might as well shell out the extra ~$100 if I'm not absolutely sure what I'm putting in there

[Gospeedracer]

I changed the diff oil as soon i got my car at 40k. Was way below the fill hole. Drained maybe half a liter. I filled it with royal purple 75w-90 and haven't had any issues within the past 30k.(I definitely drive the car and have hit the rev limiter in 6th numerous times) I was planning on flushing this week. I'll report back on what it looks like.....hopefully not a glitter party.

[KeelTiii]

Originally Posted by Gospeedracer

I changed the diff oil as soon i got my car at 40k. Was way below the fill hole. Drained maybe half a liter. I filled it with royal purple 75w-90 and haven't had any issues within the past 30k.(I definitely drive the car and have hit the rev limiter in 6th numerous times) I was planning on flushing this week. I'll report back on what it looks like.....hopefully not a glitter party.

Is that a GL-4 or GL-5 fluid? Some brands offer both in the same container.

[zinner]

You don't need more than 1 qt of fluid. The weight depends on your intended use. I use 75w140 because I have the M-LSD and it see's track use (more heat). I would just hit up the redline, motul or whatever fluid you wanna use and look at their application guide. That is pretty much it.

The capacities are in the images below. I was about to get most of it out of the diff through the fill hole with a cheesy hand pump.

View post on imgur.com

[pw0n]

Originally Posted by zinner

You don't need more than 1 qt of fluid. The weight depends on your intended use. I use 75w140 because I have the M-LSD and it see's track use (more heat). I would just hit up the redline, motul or whatever fluid you wanna use and look at their application guide. That is pretty much it.

The capacities are in the images below. I was about to get most of it out of the diff through the fill hole with a cheesy hand pump.

View post on imgur.com

Thanks for the instructions!

Ended up going w/ OEM fluids as I don't see anything conclusive and it's not going to be something I do frequently.

Link if anyone is interested, https://www.fcpeuro.com/products/bmw...ml-83222295532

[F32Fleet]

ECS