I have a 1990 535i with a LSD. Bentley calls for "BMW SAF-XLS Synthetic Oil". The dealer says to use 80/90 gear oil, "that's what we use". Me being skeptic I am, I figured I'd ask you guys before throwing the wrong stuff in my differential.

bump

In my e28 535i with LSD, the owners manual says to use 90W Hypoid gear oil. I use Royal Purple Max Gear.

Hands down the best oils:

Red Line 75W90 Gear Oil for the differential
Red Line MTL or MT-90 for manual transmission

Need 2 quarts for each.

Castrol saf-xj 75w/140 for LSD. Do NOT put regular gear oil in it!

I have the same exact car with the same exact diff......do not use redline 75-90....I used it and had problems. the diff was cooking - very hot. After the diff warmed up the diff would lock up slightly around turns and make a funny noise....USE EXACTLY WHAT BMW RECOMMENDS!!! I believe 80-90 weight....I think. After I changed the diff oil the problems went away....I know everybody says use redline, take from somebody who did it....don't use it.

bumping this up, any more opinions on gear oil? Seems Redline left a bad taste, can anyone refuite that?

On my 90 535i, 5spd, 108K miles, I've used Redline synthetic in both my manual tranny and rear diff with NO problems. My last change at 97K, I tried Royal Purple. Seems to work fine and the trans shifts "as smooth" as Redline.

However, Brett Anderson, BMW Master Tech has stated that Redline is not the cure-all and has seen poor performance when it was used. He recommended that you try it and if it doesn't seem to work, go back to regular BMW dino stuff.

I have the same exact car with the same exact diff......do not use redline 75-90....I used it and had problems. the diff was cooking - very hot. After the diff warmed up the diff would lock up slightly around turns and make a funny noise....USE EXACTLY WHAT BMW RECOMMENDS!!! I believe 80-90 weight....I think. After I changed the diff oil the problems went away....I know everybody says use redline, take from somebody who did it....don't use it.

I ended up trying Mobil 1 75W90...which caused the exact problem as stated above. When cold, the rear locks around turns causing this groan/chattering sound. When it warms up, it seems ok, but I think I should change it out.

Anyone know which brand of oil comes in 80W90? I assume that's what the dealer meant by 80/90 oil. I could not find anything that came in 80W90...

http://www.warrenernst.com/downloads/z3_differential.pdf#search=%22BMW%20SAF-XLS%20Synthetic%20Oil%22

Apparently the SAF-XLS oil has been replaced with SAF-XJ.

Part numbers are listed, but it's not clear whether it comes in containers you can purchase. It appears that it comes in big drums...

If you put 'normal' 75/90 or 80/90 gear oil in an LSD diff, you should add some 'limited slip additive' to the oil to reduce that cold/hot low-speed lockup and chatter. Some of the more expensive or more specific oils might already have this additive, but Mobil and Redline normally do not, IIRC.

I have Mobil 1 Synthetic Gear Lube LS 75W-90 in my differental. It works great.

Redline 75W90 has the friction modifiers that keep your limited slip from excessive lockup. Redline 75W90NS does not have the friction modifiers. I've used the 75W90 for 300,000 miles (uh, with scheduled changes) without any problems.

http://www.warrenernst.com/downloads/z3_differential.pdf#search=%22BMW%20SAF-XLS%20Synthetic%20Oil%22

Apparently the SAF-XLS oil has been replaced with SAF-XJ.

Part numbers are listed, but it's not clear whether it comes in containers you can purchase. It appears that it comes in big drums...

so what did you end up going with?

so what did you end up going with?

I went with Mobil1 75w-90, but just recently switched to Mobil1 75w-140 since after doing some research for my M3 it looks like 75w-140 is the proper weight for both factory required fills (Castrol SAF-XLS then, Castrol SAF-XJ now).

Almost $15 a bottle for M1 75w-140....damn oil prices sux.

Amsoil Severe Gear 75/90. Works great for me.

Can someone tell me where to get a 14mm hex. I have been to every auto parts store and no one has one, I have went to sears and I can't find one. One auto parts store has one but its too long and I don't want to cut it. Just wondering because the diff bolt on mine is 14 mm

Snap-on has that 14 mm hex...at a price. Has anyone used the royal purple 75 - 90 in the 535 diff (LSD). i'm changing all fluids to royal purple this weekend ..10-40 in the crank, max atf in the slushbox...but is the r/p 75/90 ok in the diff?

what a timely thread... I was just wondering what to refill my 3.23 LSD with... since I'm not big on buying "mystery" formulas from dealerships.

Redline or Mobil 1 75W-80 here.

The socket can be had from Snap-On (I think) or Facom. I personally have the Snap-On in the 17mm (for Getrag 260 transmissions) and the 14mm in the Facom.

Redline or Mobil 1 75W-80 here.

The socket can be had from Snap-On (I think) or Facom. I personally have the Snap-On in the 17mm (for Getrag 260 transmissions) and the 14mm in the Facom.

you have the p/n's?

Facom stuff starts here:
http://www.pro.facom.fr/CatalogueGeneral/Catalogue/PAG-CAT-03.aspx

14mm is D.107-14
17mm is D.107-17

Snap-On is apparently only a 17mm and is CPT110A
http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=12032&group_ID=1611&store=snapon-store&dir=catalog

For cars with the ZF 5spds, the Hazet 2760 is nice.
http://www.hazet.de/prod_pdf/017%5C017638ba.pdf

Maryland Metric (http://www.marylandmetric.com/) for the Facom and Hazet
Ultimate Garage (http://www.ultimategarage.com/) for the Facom
Zelenda (http://www.zelenda.com/) for the Hazet

Call all of the above for availablity.

17mm is available at sears, if anyone has one near them.

17mm is available at sears, if anyone has one near them.

Got mine at sears also.

17mm is available at sears, if anyone has one near them.

Got mine at sears also.

Might be fine for the E34 transmission tunnel where you have tons of room, but it'll never fit in the E30 tunnel as its too long.

Facom stuff starts here:
http://www.pro.facom.fr/CatalogueGeneral/Catalogue/PAG-CAT-03.aspx

14mm is D.107-14
17mm is D.107-17

Snap-On is apparently only a 17mm and is CPT110A
http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=12032&group_ID=1611&store=snapon-store&dir=catalog

For cars with the ZF 5spds, the Hazet 2760 is nice.
http://www.hazet.de/prod_pdf/017%5C017638ba.pdf

Maryland Metric (http://www.marylandmetric.com/) for the Facom and Hazet
Ultimate Garage (http://www.ultimategarage.com/) for the Facom
Zelenda (http://www.zelenda.com/) for the Hazet

Call all of the above for availablity.

$25 plus shipping for one 14mm socket is steep. Does anyone else know where to get one, I would really like to change mine since I just got the car.