Transmission and Diff Oil

[Smudgemanuk]

Hi all,

I know there has been lots of threads on this subject over the years and yes I have read as many as I can

Transmission
Some mentioned that the transmission oil used depends on the sticker on the box.
My sticker is yellow
So what oil is best for it? People recommend redline d4 but I dont know which sticker that is suitable for


Diff
It seems to be a very 50/50 split between people who put 75w-90 and 75w140 in the 25% torsen LSD's so I assume is does not matter too much
I am slightly more inclined to go for 75w-90 as it will be a daily driver even through winter, so the diff will be on the cooler side most of the time
I assume that logic tracks....

Any advice much appreciated, thank you

 

[AntStark]

Diff doesn’t matter so much..just go for the best quality you can afford as a) price difference isn’t that great and b) Unlikely to need doing again unless you plan doing spaceship miles. I went for Castrol Transmax as it was on offer at Opie

 

[Smudgemanuk]

Bump

 

[Nodzed]

75W-80 or 75W-90 Any good quality GL-4 rated fluid, dont use GL-5 for the box
75W-90 for the diff, as said any good quality brand.

 

[Neil Wilson]

I use Fuchs oils in my 2.8. For LSD they recommend Titan Sintopoid Sae 75w 140. For manual g/box with yellow sticker it’s Titan Sintopoid Sae 75w 80 if orange sticker it’s Titan atf 4000.

 

[OldFogey99]

For me:
Z3M Diff: Castrol SAF-XJ+FM Transmax Limited Slip Fluid - 75w-140
Trans -ZF S5D 320 Z: BG Syncro Shift II

Both have been good for me -who knows... I waffle back and forth over whether either one of those is "right" all the time.

 

[GZed]

75W-80 or 75W-90 Any good quality GL-4 rated fluid, dont use GL-5 for the box
75W-90 for the diff, as said any good quality brand.

Hi Niall, I was under the mistaken impression that GL ratings were backwards compatible? ie “GL-4 or higher” would be ok
What is the difference between GL-4 and GL-5, and why is GL-5 no good for the box?

…and what does GL even mean?

 

[OldFogey99]

My understanding is (super-simple version) that GL-5 can corrode the synchros.

 

[OldFogey99]

Here ya go... pretty good explanation about GL-5 in transmissions from the "all knowing" interwebs.

 

[TJS]

I wouldn't get to hung up on the BMW recommended brand and type of oil or colour of the label. The original Z1 recommended gearbox oil is Mobil SHC 630 (a synthetic SAE90 oil) which is only sold in 20 litre and 200 litre drums and is very expensive. Ask BMW what the they currently recommend and they are unable / refuse to give an answer. Most Z1 owners have subsequently switched to synthetic Redline MT90 with an improved gear change when cold and it also quietens the usual Getrag layshaft rattle when warm and stationary.

https://www.opieoils.co.uk/p-1020-red-line-mt90-75w-90-gl4-synthetic-manual-gear-oil.aspx?srsltid=AfmBOoqLAh2ncY91D-WGFL0RcaAlbYez71GM9wLnjicTVSEPCN4VCbRz

 

[Nodzed]

Hi Niall, I was under the mistaken impression that GL ratings were backwards compatible? ie “GL-4 or higher” would be ok
What is the difference between GL-4 and GL-5, and why is GL-5 no good for the box?

…and what does GL even mean?

GL-5 oil is incorrect for a BMW Z4 E89's gearbox because its high concentration of extreme pressure (EP) additives, particularly sulfur-phosphorus, is corrosive to the "yellow metals" (like brass and bronze) found in the synchronizer rings of manual transmissions, causing premature wear and potential damage.

 

[Nodzed]

…and what does GL even mean?

Gear Lubricant.