Differential Oil

[wyshyvanuk]

Would anyone care to take a stab at identifying the correct part number for the BMW 1 liter size of gear oil for a 2008 Z4 M Roadster? FWIW the differential is not making any odd noises, but I don't know what oil is in there now, nor do I know if it's ever been changed. Car has about 44K miles. The amount of contradictory information about this issue is astounding, or (and I don't discount this possibility) I'm an idiot at searching the internet. Extra credit for the correct 1 liter size of transmission fluid. Thanks for any help!!!

[kaybat]

this is what i used,no problems:
https://www.redlineoil.com/75w140-gl-5-gear-oil

[racerbruce]

Originally Posted by wyshyvanuk

Would anyone care to take a stab at identifying the correct part number for the BMW 1 liter size of gear oil for a 2008 Z4 M Roadster? FWIW the differential is not making any odd noises, but I don't know what oil is in there now, nor do I know if it's ever been changed. Car has about 44K miles. The amount of contradictory information about this issue is astounding, or (and I don't discount this possibility) I'm an idiot at searching the internet. Extra credit for the correct 1 liter size of transmission fluid. Thanks for any help!!!

BMW OEM Differential Fluid:3 83-22-2-282-583 Hinterachs-Getriebeol SAF-XJ: 832514

BMW OEM Screw Plug With O-Ring: 2 33-11-7-525-064: 339500

[KevinM]

Good information here:

http://www.zpost.com/forums/showthread.php?t=537104

and here:

http://www.zpost.com/forums/showthread.php?t=1219125

Seems OE, RP or Redline are all fine.

[wyshyvanuk]

Well, now, two quarts of Redline for $37.90 or 1.5 liters of 83222282583 for $147.51. Jeeeez, guys, I'm scratching' my head. Both of these oils contain the "friction modifiers" mentioned by BMW.
There's a January 2014 BMW Technical Service bulletin that specified 83221470080 (55 liter)/83221467993 (1 liter) for "All E46 M3, E60 M5, E63/E64 M6, E85 M Roadster, E86 M Coupe". This, AFAIK, is the oil without friction modifiers.
Even more fun: there's at least one post that maintains the 83222282583 part number is a kit that includes all three .5 liter bottles. In other words, the pricing should be about $50, not $150.
Can friction modifiers harm the Z4 M differential? Probably not. Does that differential require the friction modifiers? I'm on the border of not being convinced that they do.
If I had to change the oil right now, I'd choose the one with friction modifiers, and I'd be looking at the Redline with a great deal of affection.
Thanks for any further help.

[XMetal]

My view is that if you don't know what's in there and don't want to do it twice, then just put in the OE fluid with the FM booster. It cost a bit more for the fluid, but you won't have to pay for labor twice if yours end up making noises without FM booster. BUT, if you feel adventurous and want to experiment, then try the cheaper fluid and add FM booster as needed.

The OE part numbers are (the latter one is with FM booster):

Castrol SAF-XJ PN # 83 22 1 467 993
Castrol SAF-XJ + FM PN # 83 22 2 282 583

FYI - 83222282583 is only for ONE 0.5 bottle. The part number for the kit does cost about $150

[wyshyvanuk]

Thanks, everyone, for the information!! I'll chummy-up to friction modifiers. BMW or Redline? Still on the fence. I'd actually be more in favor of using the Redline, if the BMW stuff were not so expensive. Difficult to believe that there's not something that BMW has that justifies the cost. Am I naive? I've been called worse. Thanks, again.

[ZAR4MC]

Hey bud, I've tried Castrol LS Oil, Liqui Moly LS Diff Oil and bmw LS diff oil with friction modifiers. in my own experience building E46M3, E85M and E86M diffs, The OEM with Friction modifiers worked the best... The diffs where silky smooth after the rebuild...

I built one diff and used normal Castrol LS Diff oil, after the diff build, there was still the grinding sound within the first few miles, after it warmed up it was fine so i then switched over to the BMW oil with Friction Modifiers and the diff was silent after that.... So my advise is cough up for the BMW oil, worst case: its good enough to last you another 8-10 years.

[bosstones]

For diff, I just use the OE SAF-XJ w/ FM.

For gearbox, I used Synchromesh last time but will likely try one of the more common brands (Redline, Amsoil, or Royal Purple).

[wyshyvanuk]

Well, I guess its a field trip to the dealership this week. Thanks, again, for all the input....just what I needed.
Ted