944 Turbo S transmission oil confusion?
10-11-2009, 04:34 PM
#1
Racer
Thread Starter
944 Turbo S transmission oil confusion?
Decided to change the transmission oil myself this time which has led to some confusion regarding what really should go into the transmission if you have an LSD.
The spec from the latest workshop manual I could find, dated 1991, states on page 34-1 that the 016 R/S transmisison should use 75W90 to API GL-5 or SAE80 to API GL-4.
First I thought about Redline MTL or MT-90 but since Redline states on their web that these shouldn't be used for hypoid-type differentials they don't seem like the right choices.
I then checked four 75W90 API GL-5 oils, Redline 75W90, Mobil1 75W90 LS, Shell Transaxle Oil 75W90 and Motul Gear 300 and this is where it gets confusing.
All of them are have the same API spec but Redline clearly states that it contains the correct amount of friction modifiers (FM) for LSD. Mobil1 adds the designation "LS" after their "75w90" (not sure if this is just a naming or an API spec?) to indicate correct FM. Shell states nothing but it is Ferrari and Porsche approved (I think more or less all modern Ferraris and Porsches have LSDs?). Motul clearly states that is is NOT suited for LSD type transmisisons..... and they all have the same basic spec ???
I haven't found any straight SAE80 GL-4 but I guess a 80w140 would work but since the GL-5 spec contains additional EP-additives making it better suited for rough use and my car only sees track use I am leaning towards the GL-5 spec. I know that there are some worries regarding the EP additives being corrosive on bronze details (synchro rings) but I haven't heard of anyone having actual problems with this.
So, any ideas on if the Shell oil is OK for LSDs or which oil I should choose (Swepco 201 seems to be hard to find over here).
/Dea
The spec from the latest workshop manual I could find, dated 1991, states on page 34-1 that the 016 R/S transmisison should use 75W90 to API GL-5 or SAE80 to API GL-4.
First I thought about Redline MTL or MT-90 but since Redline states on their web that these shouldn't be used for hypoid-type differentials they don't seem like the right choices.
I then checked four 75W90 API GL-5 oils, Redline 75W90, Mobil1 75W90 LS, Shell Transaxle Oil 75W90 and Motul Gear 300 and this is where it gets confusing.
All of them are have the same API spec but Redline clearly states that it contains the correct amount of friction modifiers (FM) for LSD. Mobil1 adds the designation "LS" after their "75w90" (not sure if this is just a naming or an API spec?) to indicate correct FM. Shell states nothing but it is Ferrari and Porsche approved (I think more or less all modern Ferraris and Porsches have LSDs?). Motul clearly states that is is NOT suited for LSD type transmisisons..... and they all have the same basic spec ???
I haven't found any straight SAE80 GL-4 but I guess a 80w140 would work but since the GL-5 spec contains additional EP-additives making it better suited for rough use and my car only sees track use I am leaning towards the GL-5 spec. I know that there are some worries regarding the EP additives being corrosive on bronze details (synchro rings) but I haven't heard of anyone having actual problems with this.
So, any ideas on if the Shell oil is OK for LSDs or which oil I should choose (Swepco 201 seems to be hard to find over here).
/Dea
10-11-2009, 05:36 PM
#3
Rennlist Member
Where is 'over here'?
I wonder how relevant ZDDP is in tranny oil?
I wonder how relevant ZDDP is in tranny oil?
10-11-2009, 08:26 PM
#4
I run it in my car (86 with sport option LSD) and change it every 2 years...AMSOIL MTG 90....period
http://www.amsoil.com/storefront/mtg.aspx
http://www.amsoil.com/storefront/mtg.aspx
10-12-2009, 03:20 PM
#6
Racer
Thread Starter
"over here" is Sweden
Not sure why Redline themselves states that MT-90 should be used in our type of diffs? but it makes me a bit suspicious...
The Amsoil is GL-4, since it is a trackday car I think the increased toughness against pressure that comes with GL-5 is good, maybe the Amsoil "Severe Gear 75w90 GL-5" is better?
The Delvac looks good but no mentioning about LSDs?
/Dea
Not sure why Redline themselves states that MT-90 should be used in our type of diffs? but it makes me a bit suspicious...
The Amsoil is GL-4, since it is a trackday car I think the increased toughness against pressure that comes with GL-5 is good, maybe the Amsoil "Severe Gear 75w90 GL-5" is better?
The Delvac looks good but no mentioning about LSDs?
/Dea
10-13-2009, 03:14 AM
#7
Racer
Thread Starter
Decided to go with Pennzoil/Quakerstate fully synthetic 75W90 GL-5. I like the fact that they state that it is non-corrosive on bronze :-) (and LSD compatible)
Shell or Mobil1 or some of the other would probably work as well and there are no major price differences but I like it when a manufacturer is clear on how their products work.
/Dea
Shell or Mobil1 or some of the other would probably work as well and there are no major price differences but I like it when a manufacturer is clear on how their products work.
/Dea
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10-13-2009, 03:12 PM
#8
Racer
Thread Starter
Some interesting info http://www.synthetic-oil-tech.com/Ge...te%20Paper.pdf
Seemes that AMSOIL has ordered this test.
/Dea
Seemes that AMSOIL has ordered this test.
/Dea
