AchillesGr

iTrader: (1)

guys,
i searched many threads about diff and tranny oil and the most available in my are is the mobil1.
i saw that everyone talk about the mobil 1 75w90 but from my search i found two versions : the "mobilube shc 75w-90" and "mobil 1 ls 75w-90"
both are advertised under the mobil 1 brand and i want your opinion on what is the suitable.

http://www.mobil.com/USA-English/Lub..._LS_75W-90.asp

http://www.mobil.com/Sweden-English/...SHC_75W-90.asp

the sch is half the price of the ls but is it suitable?

thanks!!!

no_more_rice

LS or Amsoil MTG

dgeesaman

iTrader: (7)

Do not us the LS. It is rear axle lube that has contains a sulfur-phosphorus EP package and limited slip additives. This is not good for synchronizer wear and performance. It is however ideal for the rear axle.

Use the SHC 75w-90 in your transmisson. It is designed for use in synchronized transmission applications. I would not however use this in the rear axle because the EP package is not as robust.

David

no_more_rice

oops, for some reason I thought he was referring to the diff for Mobil1, my bad

AchillesGr

iTrader: (1)

Guys,
thanks!!!

arghx

iTrader: (3)

I've used the Mobil 1, it works fine and it's not too expensive.

AzEKnightz

iTrader: (24)

USE NEO, you could NOT be happier with it!!!!

-AzEKnightz

Monkman33

iTrader: (28)

Neo.

DaveW

Maybe his choice is very limited and doesn't include many of the preferred lubes (Greece).

Dave

AchillesGr

iTrader: (1)

guys ,
thanks again for the info.
as i stated i do not have many choises.i do not have NEO....
i can find redline but costs about 25$ / lt . i think it is overpriced here in greece.
Mobil 1 is easyer to find but there are two choises:

the "mobilube shc 75w-90" and "mobil 1 ls 75w-90"

http://www.mobil.com/USA-English/Lub..._LS_75W-90.asp

http://www.mobil.com/Sweden-English/...SHC_75W-90.asp

the sch is about 10$/lt
the Ls is 20$/lt

Arghx, are you refering at the sch (good price)? did you used it both in dif and tranny?
thanks

dgeesaman

iTrader: (7)

You may find some other suitable lubes from European manufacturers like Elf or Shell.

Dave

AchillesGr

iTrader: (1)

Dave, thanks
do you have any experience with shell?can you suggest any type?
shell is easy to find here.

beckrx

iTrader: (18)

amsoil gl4 mtgqt

dgeesaman

iTrader: (7)

Amsoil is not a global company and does not abide in Greece.

I had a look at the Shell website, which says you should have access to this:
Shell Getriebeöl EP: synthetic GL-4 gear oil - ideal for synchromesh transmissions
Shell Spirax ASX 75w-90: Super high performance axle oil (use this in your differential)

I don't know the details of the Spirax though because the data sheet was not available in English.

Dave

AchillesGr

iTrader: (1)

hi again,
i am still searching. i visited shell website and found for mazda rx7:

http://www.shell.com/home/page/produ...lubematch.html


official shell recomends the below for the FD:

Manual Transmission :
Premium SPIRAX AX 80W-90
or Standard SPIRAX A 80W-90

Differential :
Premium SPIRAX ASX 75W-90
or Standard SPIRAX A 80W-90

all spirax A, Ax,ASX are gl5

there are also a gl4 line named G, GSX.

can i use the gl5 series?
do any of you have experience with any of the above?
with my search at these days i found that the gl4 and gl5 are completely diferent oils.
the workshop manual sayes: use gl4/gl5

thanks again.

dgeesaman

iTrader: (7)

I agree with the options provided by your search. You can't really go wrong, so at this point you can either just go with it or try to optimize the selection further.

I happen to believe personally that GL-4 gear oils work better in synchromesh transmissions where GL4/GL5 is specified. Looking down the list, the Getriebeoel is specifically for Volkswagens but the characteristics of the oil (synthetic, designed for synchromesh action) are desirable for the FD transmission also. In my humble opinion.

GL-4 and GL-5 oils are sometimes very similar, and sometimes very different. Some GL-5s are stated to never use in a synchromesh transmission. I do know that this transmission was designed when GL-4 was the industry standard and that using lower friction oils can lead to less smooth shifting.

As for the rear axle, I believe in going for the highest EP and synthetic base lubricant. FD differential gearing does wear out and in my opinion you can't have too high performance lube in your differential.

no_more_rice

^ and change it every 15k - many never change it. I plan to try the Mobil 1 LS next time

AchillesGr

iTrader: (1)

guys,
i am a bit confused.

the Ep package increses the slip or decreses it?(for the discs to bite each other)
the EP package is for limited slip diferentials only or it is for synchros too?(where we need this bite too)
aren t the limited slip and synchros working similiar?so why the EP package is suitable for LS difs and not to synchro trans?
if a diferential is limited slip do i need the minimum lubrication?

If an oil (like mobil 1 LS) is for limited slip , can i use it to NON LS difs but not vise versa?

thanks

DaveW

a) EP additives increase the resistance to wear. They are not necessarily designed with friction coefficient in mind. However, they usually reduce friction.
b) see a. But, also there is more to whether EP lubes are suitable for LS and synchros than just being EP. Other friction modifiers may be added for LS. In my experience, EP lubes CAN be OK for synchros. It depends on the exact properties of the lube.
c) see a & b.
d) No. Minimum is not good. A lube designed for the particular application (synchro trans, open diff, Torsen diff, clutch type LS) is usually the best.
e) LS lubes, as noted above, usually have friction modifiers so that the LS it is intended for works properly. So, IMO, use non-LS lube for open or Torsen diffs, and use LS lube for the intended LS applications (usually clutch type LS).

Bottom line: For our Torsen diff, use a good GL5 EP lube, and for the trans, opinions vary, but either GL4 or GL5 (GL5 has EP additives) will work, but some will work better than others (especially for smoothness in shifting).

As you have seen, there are many, sometimes conflicting, opinions on this subject, so use your own judgement, depending on what is available, and personal experimentation for synchro function.

For me, any many others, the NEO 75W90 EP works very well in both the trans and diff.

DaveW

To re-emphasize: Dave Geesaman and I have both covered the major criteria for gear oil selection, and Dave G provided some references to lube that you should be able to get. Dave G also has more direct professional experience in this than most, including me. From here on, it's up to you. And, don't be surprised or disappointed if you have to try several different trans lubes to get the shifting "feel" that you desire.

DaveW

AchillesGr

iTrader: (1)

Dave and Dave,
thanks for the help.

Dave G in post #3 state that the LS is ideal for the rear axle .that is the cause that triger my questions.
if it is for LS aplications how it is ideal for a non Ls aplication. is t a type mistake?

Dave W:
in your post #19 /e you say the obvius for me: use the Ls for LS or disc aplications.
i think stil i am missing something....

aren t the synchros and LS difs work similiar?(taking advantage the friction betweeen materials?
so someone could come to the conclusion to use LS oils for trans? and non LS for torsen difs?


thanks

dgeesaman

iTrader: (7)

In the beginning we were comparing two oils. Of those two, the LS is more suitable for the rear axle because of the EP package. The LS additives are of no benefit in the FD Torsen and may not be as ideal as a similar lube without LS additives.

If you can find a 75w-90 synthetic GL-5 gear oil without LS additives, that is arguably the most ideal lube for this differential.

David

DaveW

If I remember correctly, the Torsen (worm-gear LS type) was designed with standard EP (not LS-specific) lubricants in mind. So a LS-specific diff lube is not, in my opinion, required, and the friction modifiers for LS applications could cause unwanted wear or less smooth limited slip (torque biasing) action.

Yes, in principle, synchros and clutch LS work similarly. However, the materials that provide the friction are different, and require different lubricant properties to work ideally. The LS-specific lubes are designed for the LS materials, and not designed for the brass synchros.

Dave

AchillesGr

iTrader: (1)

thanks guys!

here is a link to shells spirax asx if you want to take a look as very experienced you are.
i cannot find any info about EP package in it.

http://www-static.shell.com/static/c...cants/1-05.pdf



http://www.shell.com/static/global/d...ax_asx_gsx.pdf


here is the spirax AX for the transmision:

http://www.shell.com/static//global/...irax_ax_gx.pdf


http://www.shell.com/home/page/produ...lubematch.html

---------------------------

official shell recomends the below for the FD:

Manual Transmission :
Premium SPIRAX AX 80W-90
or Standard SPIRAX A 80W-90

Differential :
Premium SPIRAX ASX 75W-90
or Standard SPIRAX A 80W-90

all spirax A, Ax,ASX are gl5
--------------------
the strange is that for transmision the AX is recomended by the shel but in the AX description sayes :

"Automotive transmissions
Heavily loaded axle drives and non-synchronised
transmissions."

what is going on?


thanks again..

AchillesGr

iTrader: (1)

in this sheet for Ax/Gx oils :
http://www.shell.com/static//global/...irax_ax_gx.pdf

it is stated:
"The Spirax GX series is recommended for use in all
heavy duty on-road and off - road manual transmissions
that specify a GL-4 product. The Spirax AX series is
recommended for use in heavily loaded axle drives in
on-road and off-road applications where a full GL- 5
product is specified. It is also suited for non-synchronised
transmissions where a GL- 5 product is called for."

so if the Gx is for synchro trans why shell recomends the AX?