Unkle

Hi

Has anyone used Shell Fully Synthetic GL5 Spirax?

THe reason i ask is we supply a few performance specialist places with it. So i contact Shell Technical who informed me that the GL5 Spirax is a fully performing GL5 compared to some other leading brands. When i asked why i was informed that some other brands state GL4 and GL5. Castrol Universal for example is GL4 - GL5 which means they aren't a true high spec GL5. Some are also only synthetic based.

So i contacted OPC for a non Shell view who also said Shell GL5. As its only available in 20ltr drums to the trade, therefore i will have 15ltr sitting around if its no good, I thought i would check.

So has anyone had it fitted and can give a review?


Here are some Spirax ASX specs (from a Shell Agri leaflet)

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

Unkle

After no replies and with much internet trawling I decided that a GL5 is better than a GL4/GL5 spec. Most seem to fit the Mobil SHC oil or the Castrol Universal Gear oil, but both oils are GL4/GL5 spec. But I understand they fall short of the full GL5 oil and are something in the middle or slightly compromised for the GL5 full spec. I'm not sure how this is possible as a GL5 is a GL5 but perhaps an additive to work in GL4 applications is removed, added or altered.

Anyway I am picking up some SX75w90 GL5 semi synthetic oil today, (that isn't universal GL4/GL5 but only GL5). http://www.commaoil.com/productsguide/view/6/182/SX5L

Doing a search on here doesn't return many results either, so if anyone has more info it would be good to here it. Any evidence to corroborate the above comments or contradict them based on GL4 GL5 technology would be great.

Thanks in advance

Unkle

I know it seems like i am talking to myself (probably not the first time ). But I think I need to add to this GL4 GL5 debate with a bit more info.

I have now spoken to Castrol, Shell and Comma Technical dept. Comma and Shell both specify GL5 and funny enough they do a straight GL5 and GL4 separate oils for various other applications, but its easy to think its because thats what they make.

I contacted Castrol who I know make a universal GL4/GL5 oil to find out what they do and why, they explained the reason behind this apparent contrast with other oil manufacturers. The Castrol and presumably Mobil SHC GL4/GL5 will contain a Zinc modifier to simulate the GL5 and lower GL4 spec. This simulates the Sulphar additive used in straight GL5 applications to greatly reduce friction/leaching at high temp (thats why it smells so bad), but when I was asked what car it was for, my 964, I was told I should use a straight GL5 preferably Fully Synthetic (as the base oil is to a higher spec) and not a GL4/GL5 oil.

So the bottom line from even the company that makes a universal GL4/GL5 is USE A GL5 ONLY SPEC preferably Fully Synthetic or replace within change mileage/age requirements a Semi Synthetic. But don't go for a GL4/GL5 as the Zinc Modifiers that are trying to simulate a fully GL5 capability are not up to the job in High EP (extreme pressure) applications.

bgiere

Thanks good info here.

boxsey911

I for one have been enjoying your ramblings on the subject

GTgears

Unkle,
That Shell oil you have been considering is a very good oil. While it's not generally available here in the states, we have been recommending it to our European customers for some time now.

Regards,

Matt Monson
Guard Transmission LLC

Unkle

I know I do go on a bit lol

On gearbox oil spec I couldn't find a great deal on here, perhaps i am a bit obsessive on things like this, I have to know the reason why some do one thing and some do another.

Thanks I would have loved to have used the Spirax as our performance customers also recommend it, but 20ltr is a lot to have for the next 10+ years as i do so few miles. But I went for the Comma Semi as I don't track often and will only cover a modest 1500 miles a year. Comma are FIA F2 Tech partners and produce oils for a lot of companies in there individual bottles , so should be fine.

P.S. would be nice if a mod could change my title to Gearbox Oil (as I had trouble searching for the thread)

Unkle

I find something very therapeutic about changing oil. You know its done and you know its done how you like. Nothing against Independents or OPC, but do they really drain it fully, Leaving it for a few hours, then flush through a little to get the last bits of rubbish out? Cleaning the undertrays to remove residue of past CV leaks or overflow?

I know its not seen but it sure makes me feel better

I used just over 5 ltrs in the end, due to the little bit of flush, gearbox has had a new mount (after checking history) and it still displays the label and complete galvanised coating. The oil was clean without residue.

The diff was far from clean. I think a inner CV gater had burst in a previous life and it took a while to get to even this standard. Typically the garage never cleaned anything (as its all costs money while its on the ramps taking up space). The diff oil was also very dark more like water viscosity but also without residue.

Just filled and set it on level ground, allowing a little to flow out to get it right as i assume thats the general rule.

Unkle

Took the car for a run today and its better with a feel than can only be described as (without the notchy change). The gearbox seemed lethargic before like i was changing slightly ahead of the synchros or something. Also I seem to get less groaning at low revs something that indicated that I need to be in a lower gear under 2000rpm (I use a diesel around town so a little guilty here). All in all i think its improved and will see how it is after 6 months of use.