TOO MUCH INFO ON MANUAL TRANS FLUID: What to use?

[M5XTu]

I have a 2003 525i with manual trans. 147k miles.

I read some people use RP Synchromax, MTL-90 or Mobil1 75-90. Someone in one of the forums say just Dexron III or IV is just fine.

I would like to stay simple. It’s a daily.

Can I just use DEXRON III/IV?


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[taz.]

Atf is good also. Will cure the cold hard shift.

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[R Shaffner]

I have a 2003 525i with manual trans. 147k miles.

I read some people use RP Synchromax, MTL-90 or Mobil1 75-90. Someone in one of the forums say just Dexron III or IV is just fine.

I would like to stay simple. It’s a daily.

Can I just use DEXRON III/IV?


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I believe there's usually a yellow sticker on the side of the tranny that says what to use.

[ross1]

GL5** gear oil 75/80 recommended
GL is the pressure rating, you want 5. I see no reason not to use 75/90(easier to find) in Phoenix where you are pretty unlikely to experience cold shifting issues.

** Edit; NOPE GL4

[edjack]

I vote for Redline MTL.

[M5XTu]

So, any of the fluids mentioned here will work?


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[cnn]

I did the maintenance on my 1998 528i 5spMT back in 2006.

Here is the info on Redline.
I wrote it back in 2007 or so ---> tips to fill by gravity...

http://bimmerboard.com/forums/posts/189240

I use:
Man Trans: Redline MT-90
Rear Diff: Redline 75W90

[Mike WW]

GL5 gear oil 75/80 recommended
GL is the pressure rating, you want 5. I see no reason not to use 75/90(easier to find) in Phoenix where you are pretty unlikely to experience cold shifting issues.

Nope, GL5 is for diffs, not trannys. It's for hypoid gears and way to "sticky" for manual trannys, cold shifts will be terrible. Supposedly the sulphur it it will even eat up brass synchros, although I can't say I've ever heard of it happening. BMW used to spec GL4 and even single grade motor oil, but by the late 80s/early 90s they went away from that and to ATF.

On earlier cars some people use Redline MTL or a mix of MTL and MT90. And I did use engine oil way back when before I could find MTL and it worked just fine.

[sienayr]

Redline now has MTL-LV, which seems like a perfect fit your application and location. You can always call and chat with bimmerworld too about your specific car and needs, they will cut through the noise and give you sound advice. From bimmerworld website on MTL-LV:

MT-LV bridges the gap between ATF D4 and traditional MTL for vehicles in hot climates or that see significant track time. We have found that in certain hot temperatures, the ATF D4 can be too thin. On the flip side, in cold temperatures the thicker MTL was too heavy. The MT-LV is the happy medium, tested in multiple BimmerWorld street and track cars in varying temperatures and conditions.

https://www.redlineoil.com/mt-lv-70w75w

[ross1]

Nope, GL5 is for diffs, not trannys. It's for hypoid gears and way to "sticky" for manual trannys, cold shifts will be terrible. Supposedly the sulphur it it will even eat up brass synchros, although I can't say I've ever heard of it happening. BMW used to spec GL4 and even single grade motor oil, but by the late 80s/early 90s they went away from that and to ATF.

On earlier cars some people use Redline MTL or a mix of MTL and MT90. And I did use engine oil way back when before I could find MTL and it worked just fine.

Well, very interesting that you should say this.
An oil company's website(I forgot which but was in Holland)said same, that GL5 "not for gearboxes". I made the assumption(wrong) that perhaps the Bavarians, in their infinite wisdom, had preferred this oil which seems better for shock loads.
Trying to x-ref the recommended MTL LT2 to something more widely sold I kept coming up with GL5 oils. Searching again this morning I cannot repeat those results. I clearly followed the wrong trail the other day.
Thanks for the correction, I've edited my earlier post. Sorry for posting wrong info. and hope OP hasn't purchased GL5.

[Mike WW]

ross1, don't beat yourself up too badly. Even if you missed this one, you provide a wealth of info here and one of a select few whose posts I actually pay attention here.

[M5XTu]

Thanks for all the info.

I will be using GL-5 for the differential andDexron III/IV for the tranny.


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[crdiscoverer]

I have been using this in my '97 528i and it's being great, although full disclosure, it's never really cold where I live, so YMMV:

https://www.motul.com/no/en/products/gear-300-75w90

[Chedley]

Use Pentosin ATF-1 Synthetic.
Good on all ZF trannies , at all temperatures.

[ThaDoubleJ]

I just went through this same process in my brain and on the google machine. Since my car is summer only, 1000 miles a year tops, I did Redline MT-90. If it was a year round car, I'd probably be looking at one of the ATFs as that's what I took out and it seemed fine. GL-4 is correct for the heavier stuff, I researched the hell out of why, but can't seem to remember now.