Which Diff Oil?

[Flat_White]

Guys what diff oil do i need for my bog standard VY S? it has no LSD...

CHeers

[vxcalais_01]

I just changed mien last week and used Penrite Singear oil 80 (80W 140). My car has done 200,000 approx k's so i went higher. Sin gear 90 (75W90) is the original spec. Both are $50 for 2.5 litres but it only needs 1.7 litres. Rest i use for flushing. Penrite Limslip 90 is very good as well ($24?), so it Castrol and their SAF-XA etc. Get the one with additive, it doesnt matter if it has it or not, but i went for synthetic so i dont need to do it again. Friction modifiers are benficial to LSD and non lsd diffs. Shell, Mobil Valvoline all have good ones. If you gonna change regularly use the mineral ones, i used synth cause its a **** job and i dont wanna do it again hehe or at least for another 5 years.

[andyman]

I just changed mien last week and used Penrite Singear oil 80 (80W 140). My car has done 200,000 approx k's so i went higher. Sin gear 90 (75W90) is the original spec. Both are $50 for 2.5 litres but it only needs 1.7 litres. Rest i use for flushing. Penrite Limslip 90 is very good as well ($24?), so it Castrol and their SAF-XA etc. Get the one with additive, it doesnt matter if it has it or not, but i went for synthetic so i dont need to do it again. Friction modifiers are benficial to LSD and non lsd diffs. Shell, Mobil Valvoline all have good ones. If you gonna change regularly use the mineral ones, i used synth cause its a **** job and i dont wanna do it again hehe or at least for another 5 years.

ha, irs commos are easy as, wait until you have to do an irs falcon, ill give you a hint, you have a 15mm hose running from the diff through the wheel arch to the outside of the car

[Flat_White]

so what is the consensus then? what grade diff oil should i use in my VY?? Sin or Mineral?

[vxcalais_01]

Yeah, used a Tom Thump utility pump from Autobarn. Pumps it right in.

VYSam - Up to you how much you wanna spend. I dont use Synth in the engine, but i would use it in the diff etc. Purely because the synth seems to have more extreme pressure additives and others etc. I didnt bother to check what type of diff i had so i got with the additive just in case. People i have spoken to said if you dont need additive, doesnt matter if you have it as all the Diff oils recommended like Penrite Limslip 90 which you can use and much cheaper already has some additive in it already. Synth was $49, Limslip 90 is only like $24 for 2.5 litres. Valvoline even cheaper. I went for synth on the diff as i have never read it being bad for it. I have read professionals preferring mineral trans oil over synthetic, it was in the Street Commodores Magazine Tech tips i think where they rebuilt a tranny. But Raptor Superchargers on this site have had good use with Amsoil synthetic diff oil (have a look in the Raptor section). The Amsoil stuff is $43 for 2 litres. I decided on the Penrite Sin as it had 2.5 litres, and i could use the 500ml or so to flush before putting in the required 1.7 approx. The Limslip 90 is the right spec for our cars, 75W/80W - 90. But i went thicker as my diff has already done 200,000k's. It doesnt really matter as on startup the 80W140 and 75W90 are the same on startup, just as they get hotter they 140 doesnt thin as much. Remember they are still the same at cold temps. The heat generated in the diff i am amazed any oil will hold its viscosity after a while.

[bradcad]

Speaking of diff heat, if i could just take things on a slight tangent, drive your car at 100k's for 20 minutes, then put your hand on the diff case. It is amazing how much heat is created by massive amounts of friction and friction alone.

You know when you are onto the right diff oil when after the same drive you can comfortably hold your hand on the case. Temperature drops of 30 degrees are not uncommon. Infact I understand the ideal temperature for reduction of mechanical wear is around 80°c. (85 maybe).

Hence why VX Calais is talking about Extreme Pressure additives- this is an actual testable pressure rating, first achieved by Mobil in their gear oils when they exceeded 40 pounds timken ok.

Oil between gear teeth is compressed (fluid only very slightly compresses, if at all) to the point where it is almost considered a solid. That is how much stress diffs (gears) put on oils. And that is in a standard vehicle.

Is it any wonder when performance figures are ever increasing, driveline component failiure becomes more common?



ok sorry guys back on track.....

[Flat_White]

ok i picked up some run of the mill mineral valvoline gear oil API GL-5 80w90 oil... anyone know if this is suitable for my VY non-lsd diff?

[vxcalais_01]

The Valvoline if i can remember was sometimes like Valvoline LS90 ??? The grade and rating sounds correct. Try the Lube guides on the website.

[Flat_White]

yeah i didnt actually get LS90... i thought the LS denoted that it was the type for an LSD...

[Flat_White]

oh and the lubes guide on the valvoline website is useless for diff oil for commodores.

[vxcalais_01]

I assume the LS is for LimSlip. Yeah they only really have 1 i think. Already that oil shows you the oils are universal, limslip or not. The synthetic versions come with the sturacco additive to quieten them down already in it. This may only happen with the LSD's, not sure.

[vxcalais_01]

The valvoline is much cheaper, but is still a fantastic product, drag racers are using it even. But they just change more often. Theres a fantastic writeup on here on how to change it on a VY, have you seen it ?

[Flat_White]

nope havent seen it yet.. care to share the link??

and by the way, i filled my diff today with valvoline gear oil 80w90.... hopefully it goes ok.

[vxcalais_01]

SO you already changed it ?

[vxcalais_01]

http://forums.justcommodores.com.au/...al-oil-vz.html

For a VZ but all the same, even mentions your fluid you used.

[Flat_White]

yeah i changed it on the weekend.