[Slick_FThirty]

Hello,

I checked with my BMW dealer, and my 2013 328i F30 needs 75w85 GL1 for the rear differential and 75w85 GL2 for the front differential.

Would the 75w90 GL5 Liqui Moly Transmission Gear oil work?

When I go to FCP Euro, enter my car, and look at the recommended products, the BMW GL1 and GL2 oils are there, but they also show a 75w85 GL5 Red Line, for example.

There seems to be a lot of confusion on forums about which GL numbers are better, compatible etc.

1. Would GL5 work when BMW requires GL1 and GL2?
2. Would 75w90 work when BMW requires 75w85?

[328iX]

You seem to be confused about BMW putting G1 and G2 on their bottles, that does not mean GL-1 and GL-2 The API specification for BMWs G1 fluid is GL-4 spec and G2 is GL-5 spec

I'm running the redline 75w90 '57904' front and rear, and always have without issue. Also that's the recommended spec by Redline as well.

Higher spec is backwards compatible hence running the same fluid front and rear, it has the appropriate additives.

[Slick_FThirty]

Great answer. Thank you very much.

Did you change the bolts fill and drain bolts as well? I saw FCP euro was selling kits related to that. I was planning on just reusing the old one. But maybe that would be a bad idea?

[dmaxdmax]

I'm sure every mechanic on earth reuses drain plugs, but don't forget to replace the crush washer if the plugs have them.

I believe the transfer case doesn't have a drain, so guys are sucking out the fluid with a small hose on a vac pump.

I've been putting off changing my fluids, but need to soon, even though they're, I believe, all 'lifetime.' No one believes that, though it does make me wonder just how bad 'bad' fluids are in our diffs.

I think all my fluids came close to $450 using OE fluids from FCPeuro...so understand your considering Redline...but don't forget these will be in your car for many years, so the cost isn't really that much per year.

Check our realoem.com or newtis.info if you haven't yet to confirm what you need.

[328iX]

Originally Posted by Slick_FThirty

Great answer. Thank you very much.

Did you change the bolts fill and drain bolts as well? I saw FCP euro was selling kits related to that. I was planning on just reusing the old one. But maybe that would be a bad idea?

I did on my last F31, my current F31 I just had the shop reuse. I say if it's your first change it doesn't really matter, subsequent changes yeah I'd probably change the washer at the least.

[therealm3]

I recently did my diff with redline 75-85 GL5. That's what their site recommends. All previous BMWs I used redline 75-90.

[Roach1]

Is it okay to put redline 75-w85 gl5 in the rear ? I read somewhere that the rear should be gl4 and front should be gl5 . Idk how true that is but bimmerworld told me 75-90 for front 75-85 for rear, both Gl5

[Slick_FThirty]

Originally Posted by Roach1

Is it okay to put redline 75-w85 gl5 in the rear ? I read somewhere that the rear should be gl4 and front should be gl5 . Idk how true that is but bimmerworld told me 75-90 for front 75-85 for rear, both Gl5

Yes that's fine.

GL5 is higher grade than GL4. There is concern for GL5 being less compatible with brass. But it's fine with these diffs to my understanding. Some brands sell GL4/GL5 combo meaning it's okay to use with some of the softer metals.

75w- 90is thicker than 75w-85. Really no difference meant to confuse people and make them go to the dealership who exclusively sell 75w85. That's the only point of 85 vs 90.

I'm running 75w-90 GL5 in front and rear. Been perfectly fine.

[el_couzin]

+1 here for redline 75w85.

I also replaced all the plug. it use some kind of rubber oring seal, not crush washer.

[Roach1]

Originally Posted by Slick_FThirty

Yes that's fine.

GL5 is higher grade than GL4. There is concern for GL5 being less compatible with brass. But it's fine with these diffs to my understanding. Some brands sell GL4/GL5 combo meaning it's okay to use with some of the softer metals.

75w- 90is thicker than 75w-85. Really no difference meant to confuse people and make them go to the dealership who exclusively sell 75w85. That's the only point of 85 vs 90.

I'm running 75w-90 GL5 in front and rear. Been perfectly fine.

Cool will do thanks. BMW is stupid with their diff fluid spec recommendation.