Gear Box / Diff Oil

[DevilYellowCV8]

My 05 CV8 has now reached the 4k miles mark and it's been suggested that once the gearbox and rear diff have been 'run in', it's worthwile changing the cheap factory stuff with a better brand.



So what I'm asking is;

What brand(s) do any of you recommend from experience and should I take the car to Vauxhall to have it done (warranty issues?) or can I take it to a local (ie competant) garage.

I'm not bothered about the cost of the oil, just so long as it does what it says on the bottle!

I was going to wait until I took the car to have the headers done, but I've heard that it can help to improve the gearchange (I aready have a R/Shifter) slightly more if a better oil is put in and I can't get time off work to go and have the main work done for a while.

Also at this mileage, is it worth doing the engine oil at the same time. If so, recommendations? The oil filler cap says 5W/30.

Thanks

[stevieturbo]

I was previously using Motul 300v 15/50 in my engine, and plain old Fuchs Dexron III in the T56.

Not using the same diff as you guys, so cant offer a reccomendation.

I will be using Motul 300v 5/40 in my new engine though.

I'll also be buying some Castrol Transmax Z for the T56, which is very highly rated down under.

[comm_SS_V8]

I've currently got "GM Synchromesh Transmission" in the gearbox, Comma 5w-40 f/s in the engine, and "Morris Lodexol XFS 80W/140" in the diff. Given the recent hike in Oil prices I've opted for a good cheap engine oil that I change every 5000miles.

Upgrading the gearbox oil will definately improve shifting, or at least it did for me. Shortly after doing the gearbox oil I had Wortec install the GTS-R shifter which improved things yet again. Given what I'm hearing about the Rip Shifter it appears to be the way to go.

LSV uses Morris Oils in the diff as they are recommended by the diff manufacturer. Just fill it up and forget about it. No need for Friction modifiers. If you tend to drive sideways quite a bit then Redline 80W140 with F/M would be the better way to go. It all depends on your driving style. Both myself and Tom (A57_HSV) have used Morris and never had a problem with it. If you want a Redline product that you don't have to worry about F/M then they recommend 75w90. I know MCD used this before he sold the car. If you go down the F/M route speak to Wortec as they have the quantities down to a fine art now.

The GM Synchromesh is recommended by the guys over in the USA and so far I've found 1 supplier in the UK. It isn't cheap but it's magic stuff. As Steve says, the Aussies prefer "Castrol Transmax Z" which I was tempted to go for at the time. Just remember to use the 'overfill' procedure as detailed here to cut down on the noise until you get the RipShifter fitted.

And if the choice wasn't already confusing enough, here's a list I compiled of typical oils used by members in the UK:

Engine
======
The book states 10w-30 fully synthetic based oils. This is very difficult to get hold of in the UK, and expensive when found. Most 10w-40 Fully Synthetic SL Spec Oils are good alternatives.
Tuned engines (Supercharged, etc) are recommended to use 5w-40.
It is not recommended to use 0w-* based products as it's too thin. No actual damage has been reported by those using it though, just high oil consumption rates.

* Castrol GT Magnatec (10w-40) [UK Vauxhall's recommendation for the LS1 based Monaro]
* Comma Syner-G (5w-40)
* MOBIL SYNT S (5W-40)
* Red Line 10w30 Motor Oil (10w-30)
* AMSOIL (XLT) Synthetic 10W-30 Motor Oil (10w-30)
* Morris Multilife 5W/40 (5w-40)
* Valvoline SynPower Full Synthetic Motor Oil (10W-30)


Gearbox
=======
The book states any good quality oil meeting Dexron III (80w) specifications.

* Castrol Transmax Z
* Mobil 1 Synthetic ATF
* Red Line D4 ATF Gear Oil
* GM Synchromesh Transmission Fluid (Part#: GM-12345349)
* Morris Liquimatic Super ATF
* Valvoline DEX III ATF


Differential
============
Any 80w/140 based product.
Note: You might require some Friction Modifier to stop diff noises after changing the oil.

* Mobil Mobilube SHC (80W-140)
* MOBIL GEARLUBE VS 500 (Synthetic) (75W-140)
* Castrol SAF-XJ (75w-140)
* RedLine 80W140 Light/Heavy Shockproof Gear Oil (80w-140) - Requires LSD Modifier
* Redline 75w90 (Includes LSD Modifier) and is suitable for 'typical road use'
* AMSOIL (FGO) Long Life Synthetic 80W-140 Gear Lube
* Morris Lodexol XFS 80W/140
* Morris Lodexol SS 80W/140
* Millers CRX LS 80w140 BM


LSD Friction Modifier
=====================
* Red Line LSD Friction Modifier
* AMSOIL (ADA) Slip Lock Differential Additive
* GM Synchromesh Transmission Fluid Friction Modified: (Part #GM-12377916) [Unsure of UK stockitsts at this time]


Choosing the right oils is a complicated & time consuming exercise (as I found). I would say to people, buy the oil on the following recommendations (some may agree/disagree with the following, so choose the advise you want):

* Buy a good brand of oil and change it often rather than buy expensive oils just for their extended drain life.

* Redline, Amsoil, Royal Purple and NEO are probably overkill in most applications. Most of these also claim you can have longer drain
intervals. It's debatable whether this is a good thing or not, clean filter or not.

* Penrite, Mobil, BP, Shell, Castrol and Penzoil are all good brands and are better priced to change often....every 5,000-6,000 miles (or 6 months) is still the mark for engine cleanliness and longevity.

* Buy the best you can afford but I think there has to be a sensible
level to spend to.

* Finally, don't throw money away on additives. They are snake oil and
could very well hurt your motor.

One of the best resourced on this subject is the "Engine Oil Bible" found here: www.chris-longhurst.com/carbibles/

[comm_SS_V8]

Stupidly forgot the most important information.....quantities:

Engine Oil: 5.1 litres required
Gear Box Oil: 4.2 litres required
Diff Oil: 1.7 litres required

It's always worth having a little bit extra just in case.

It took me an hour to change all 3 oils with the car on axle stands on the drive. Not the easiest way to do it but it saved me money and I don't have a warranty to worry about.

If you bought the oil yourself the Vauxhall dealer should just charge you labour. As for taking it elsewhere I'm afraid I can't say whether it would void the warranty or not. My incling would be not, but best check with Vauxhall first.

Edited: Corrected Gear Box Oil requirements

>> Edited by comm_SS_V8 on Saturday 18th February 19:46

[DevilYellowCV8]

Wow, thanks for the info - very comprehensive.

So, the info on the oil filler cap is incorrect? or is it correct in that it is the oil that Holden put in the car on the assembly line and is still the stuff that is in there?

Thanks

[comm_SS_V8]

The 5w-30 listed on the filler cap is correct and more than likely what Holden put in there at manufacture. I took the data from the Commodore platform so things are bound to change fractionally. According to my manual Holden recommend 10w-30 so they've gone slightly thinner for the mass markets. That's no problem as I use 5w-40 anyway.

Most Northern European cars are recommended to run with, and will run quite happily on, 10w-40 but I have a personal preference to the 5w-40 during winter to make the starts easier and to get the oil to the critical areas quicker.

I wouldn't recommend going to 0w-* oils as they are just too thin. Likewise I probably wouldn't recommend going above *w-40 unless you intend to keep the car as a track day vehicle.

All the best in whatever oil you choose.

[stevieturbo]

You sure about the quantity for the box ?? I'm pretty sure its a lot more than 2.5l

I thought it was closer to 4.0l, or a little more if you overfill.

I wouldnt rate Magnatec as good oil.