'07 BMW 335i Diff Oil, 90wt vs 140wt

[4x4taco]

Ok, looks like the factory fill in my '07 335i is 75w-140 Castrol XJ or whatever. Some european synthetic. Car has 39k and the original fluid. Needs changed out. I'm on the fence weather to go with:

A- OEM Castrol 75-140 syn fluid. Gotta buy it from the dealer and bring my own jug. Have no idea what it costs per qt.

B- Mobil 1 75-140. Easily available locally. $18.99/qt. No reason it won't work as good as the OEM fluid.

C- Mobil 1 75-90. $10.99/qt. Thinner, for better MPG & power transfer. I don't race the car or cruise at 140ph so I'm not really sure Id ever really need the 140wt. I just drive spirted every now and then.



THe car is stock with 300HP and 300 #/Ft of torque. It's a 6spd manual.

 

[Doug Hillary]

Hi,
4x4taco - Castrol in Germany works very closely with BMW in the development of lubricants. This especially applies to gear lubricants. I would stick with the OEM fluid

 

[Steve S]

I would have to agree with Doug. At least go with the recommended viscosity. There is a whole lot of power running through a tiny rear end.

 

[unDummy]

In FL, you don't want a 75w90 where a 75w140 is recommended. Its there to protect either wimpy components(your rear end), or the natural aggressive driving style of the owner...

Stick with ANY full synthetic 75w140 that you can get locally. Mobil1, Amsoil, Redline, Royalpurple... are easy choices.

 

[hate2work]

Originally Posted By: Steve S
I would have to agree with Doug. At least go with the recommended viscosity. There is a whole lot of power running through a tiny rear end.


I agree also. And since it only holds about 1 quart, I would use a top notch fluid in the correct viscosity, either the OEM or this stuff from Amsoil.

http://www.amsoil.com/catalog.aspx?code=SVOQT-EA

 

[4x4taco]

10-4 guys. I didn't realize the diff was so small.. and forgot it was IRS. My Tacomas had a lot of power, towed 6,500 #'s and only ran 75-90 fine. But this is a different animal I guess. 300HP, performance car with a "small" diff that does not have axle tubes to hold a lot of lube.

 

[mechtech2]

If a mfr recommends such a thick lube nowadays, they are serious about it. They all seem to want thinner, if possible.
I see Florida, as well. Nice and warm, or good and hot!
Price the oil at the dealer. Because of bulk and no bottles, it may be reasonable.
But you make darn sure it is the stated product! You don't want some bulk dino 90 w they got on sale!
I see no problems with M1 in the right viscosity, but a rather new and nice BMW gets the nod for the factory stuff at this point, since you have a choice.

 

[Bror Jace]

I agree with sticking with the heavier fluid if spec'd ... especially in Florida.

Not sure if sticking with a synthetic is really necessary. One of the Schaeffer's blends or this stuff in 85W-140:

https://cglapps.chevron.com/msdspds/PDSDetailPage.aspx?docDataId=76979&docFormat=PDF

might do just fine.

 

[Craig in Canada]

Originally Posted By: Bror Jace
I agree with sticking with the heavier fluid if spec'd ... especially in Florida.

Not sure if sticking with a synthetic is really necessary. One of the Schaeffer's blends or this stuff in 85W-140:

https://cglapps.chevron.com/msdspds/PDSDetailPage.aspx?docDataId=76979&docFormat=PDF

might do just fine.


He's got a fairly new 335i - why nickel and dime on a quart of lubricant you change every two years max.

 

[Bror Jace]

It's not terribly expensive stuff ... but it isn't 'cheap' either. I use the 80W-90 in my S2000's diff. I'll probably change it every 15,000 miles or so ... why waste the money on synthetic when a quality mineral oil can do the job?

A decade ago I thought there was 'something magical' about synthetics ... no more.

 

[mechtech2]

Bror Jace -
Your four ball tester will be 40% cleaner if you use your Edge sword to clean them!