Importance of OEM approvals for manual transmission fluids?

[OM605]

Hi everyone.

Could someone explain what lies between OEM approvals for manual transmission fluids and what are the differences between them ? For exemple MB 235.10 or PSA B71 2330, every manufacturer has them, Volvo, VW, BMW etc. How much of it has to do with commercial agreements or simply fluids that are required for the warranty to work ?

Mercedes manual gearboxes require the 235.10 approval but it is really hard to source and the options are very few. For exemple i was looking at a cheap bottle of synthetic 75W-80 GL-4 that i can find everywhere and it had all the PSA, VW, BMW approvals and some more while something similar but with the 235.10 approval is really hard to find. What makes it so special and different ? Can i still use other GL-4 oils without it ?

I'm starting to think that this is a somewhat outdated spec for warranty purposes and that any modern GL-4 oil will do but correct me if i'm wrong. It's kind of the same thing with Mercedes rear axle, the spec is 235.7 but no one bothers with that, at least for the older cars and it never causes issues however i didn't find anything about manual gearboxes.

 

[rob1715]

This goes back a bit but I had a new 92 Geo Storm manual and changed the gear oil with an aftermarket. Shifting was stiff and much less responsive. Changed it back to OEM Synchromesh fluid and it fixed it. Wife had a 99 Nissan Sentra manual. Changed it with after market and did the same thing. Since then I will only use OEM fluid for manual. Just one story among many that may differ.

 

[zeng]

Can i still use other GL-4 oils without it ?

IIRC , an MB 235.10 covers up to 75W85 GL4.
For protection , I would pick any GL4 with 75W85 grade , or thicker at 75W90 not neccessarily following OEM recommended oil change intervals and/or life time fluid regime .

 

[OM605]

The Mercedes BEVO constradicts iself. It says 235.10 is 75W-85 but such oil doesn't even exist (75W-85 is for axles and is 235.7). 235.10 is available in 75W and 75W-80 only. The oil sold at the dealer seems to be the 75W. Maybe they made the move to this viscosity at some point because MB manual gearboxes are notorious for being hard to shift when cold.
I used a 75W-80 235.10 approved GL-4/5 and the shifts were terrible. I changed to a 75W GL-4 235.10 and it's much much nicer but the oil (Febi, with MB part number) is getting very hard to source. I am tempted to try another GL-4 only 75W or 75W-80 disregarding the approval as it doesn't seem to guarantee good shifting.

 

[OM605]

I'm tempted to use the Total oil as it is everywhere, really cheap and the viscosity is quite low for a 75W-80. It is a GL-4 only oil too. If you look at other oils carrying the MB approval they seem to be in the same ballpark as far as viscosity etc and they all carry the PSA B71 2330 too, which makes me think that they are not far appart. Total always had a strong commercial agreement with PSA here and could be the reason why it is the only approval this oil has.

Can someone give me an opinion ? Here's a link, unfortunately i wasn't able to find it in english but you can have an idea looking at the PDF.

Total Traxium 8 75W-80

 

[zeng]

The Mercedes BEVO constradicts iself. It says 235.10 is 75W-85 but such oil doesn't even exist (75W-85 is for axles and is 235.7). 235.10 is available in 75W and 75W-80 only. The oil sold at the dealer seems to be the 75W. Maybe they made the move to this viscosity at some point because MB manual gearboxes are notorious for being hard to shift when cold.
I used a 75W-80 235.10 approved GL-4/5 and the shifts were terrible. I changed to a 75W GL-4 235.10 and it's much much nicer but the oil (Febi, with MB part number) is getting very hard to source. I am tempted to try another GL-4 only 75W or 75W-80 disregarding the approval as it doesn't seem to guarantee good shifting.

You're right about MB BEVO contradicts itself is displaying viscosity grade of 75W85 under MB 235.10 listing, when the approved oil in Gear Oil MB 317 is not but a 75W80 with a Brookfield Viscosity @ -40*C of 23,500 cP , exceptionally low'ish IMO .

As you describe the MB manual gearboxes are notorious for hard to shift when , this appears a low'ish BV in Gear Oil MB 317 is favourable for its use here , however with a reduction in MOFT/operating viscosity vis-a-vis unapproved 75W80 and thicker fluids like 75W85 or 75W90 .

 

[zeng]

I'm tempted to use the Total oil as it is everywhere, really cheap and the viscosity is quite low for a 75W-80. It is a GL-4 only oil too. If you look at other oils carrying the MB approval they seem to be in the same ballpark as far as viscosity etc and they all carry the PSA B71 2330 too, which makes me think that they are not far appart. Total always had a strong commercial agreement with PSA here and could be the reason why it is the only approval this oil has.

Can someone give me an opinion ? Here's a link, unfortunately i wasn't able to find it in english but you can have an idea looking at the PDF.

Total Traxium 8 75W-80

This PSA approved Total Transmission Gear 8 75W80 GL4 of KV40 @49 cSt and KV100 @ 8 cSt but a very highish Brookfield Viscosity @ -40*C of 104,000 cP vs 23,500 cP that of MB 235.10 approved Gear Oil MB 317 detailed above .

Hence, I suspect you may encounter with hard shifting when cold phenomenon with use of this Total oil .

Should shift quality is essential/critical/important to you , I'm of the opinion that you may try to consider :
a ) RAVENOL_MTF-2_SAE_75W-80 whose BV @ -40*C is 18,800 cP ; or
b ) RAVENOL_MTF-3_SAE_75W whose BV@ -40*C is even better at 11,000 cP , caveat being either one may not have formal MB 235.10 approvals .

 

[zeng]

- double post -

 

[OM605]

Thanks for the replies. This helps me a lot understanding the requirements of the old Mercedes gearboxes. Looking at the part number, the oil i use now, a 75W 235.10 seems to be the exact same as the oil sold at the dealer.