This topic has been debated lots on this forum, throwing up many answers and opinions and as i wanted to change the gbox oil on my newly aquired Panda i thought i would spend a day doing some research.. I will keep this short but firstly most user manuals and every Fiat service centre i spoke to all say use something like an EP 80/90 oil, these are i believe are a GL4 spec oil.
So who or when was it deemed that EP, GL4/5 oils are detremental to Panda gearboxes ? Also are the internals of all Panda boxes the same ?
Maybe should we be using non EP mineral oils in boxes up to say 1986, and a more modern EP oil in later models, this is just me thinking out loud and not fact..
Taking the opinion that all EP and GL4/5 oils are bad i spoke to a major oil company and had a very interesting chat with there 'oil guru'. Giving him the info available he suggests that using a specialist oil like Millers G3 is ok if you want to spend lots of money, Search for Fiat ZC 90 and the like and you will need a fat wallet to buy this product. Anyway he was of the opinion that good old 10 or 15w40 mineral engine oil was the way to go. In fact i found on a forum that the viscosity of this is the same as a 75w90 gear oil ? i quote:
Some gearboxes actually take engine oils.
MTF (Manual Transmission Fluid) is in fact a 5w-30 engine oil.
There are cars where the gearbox runs on the engine oil, old minis for example.
For your information a 75w-90 gear oil is roughly equivalent in viscosity terms to a 10w-40 engine oil.
Link here: http://forum.atomclub.com/index.php?topic=2686.0

The 'guru' went on to say that a lot of car manufacturers are now going back to using engine oil in gearboxes with some even using ATF in manual boxes. Also high performance 4 stroke bikes use engine oil in the gbox..

I mentioned the HD40 disiel oil that Coma recomend and he thought that would cause problems from cold start up, way too thick.

So ive bit the bullet and put in a 'budget' 15w40 mineral engine oil and as yet all is fine but i will keep you posted. Oh he said to me that in the oil trade there is a saying that "any oil is better that no oil"

Let the debate continue.....

Thanks, that's pretty much as I understand the oil situation.

In short.
GL4/5 have high pressure EP additives that are bad for yellow metals in Panda gearboxes.

GL3 is fine with no additives but hard to find, Millers is about the only one.
Tutela ZC90 is just an expensive Fiat branded GL3

And 15/40W engine oil is ok too. But i'm glad you're trying it becuase it's the option i'm not too sure about, but if it works it would be a lot easier than faffing about ordering Millers online. Keep us updated.

Update on the HD 40 Comma oil....It did not seem too thick (about the same as gearbox oil and def not quite as thick as 15/40)

Few 1000mls down the line everything is fine...no diff cold or hot...Just thought i would mention it.

kev

The best in the business recommended to me 20/50W mineral engine oil

just to throw a curveball in, my gearbox has run for years on mobil shc630 which is like treacle going in. Getting worn now but that 'box has now done quarter of a million miles in 21 years with I'd guess about half a dozen oil changes. The last lot of oil was in for 6 years and 25000 miles and looked more or less the same as the fresh stuff I put in.
However... just googled the oil I got for free and frankly a rebuild would be cheaper

Re: Gearbox oil !! UPDATE

OK its been a week now since i changed the gearbox oil to 15w40 mineral engine oil. Its still early days and ive yet to take him on a long run but
i can report that all is good, The gear change is actually getting better by the day, It was a bit notchy from 3rd to 4th and sometimes it didnt want
to go into 5th at all. Its now very smooth.
Will update again after a long run. Fingers crossed all will be OK, time will tell.

Out of interest... maybe...
Page 19 of the blue Haynes manual - recommended lubricants - there is an annotation after ZC90 and Duckhams 90Z*
(the note below explains that the oil is only available in bulk and 'a multigrade engine oil such as Duckhams Hypergrade will mix fully with it, and may safely be used if wished')

This information is omitted in the later green manual though, with only ZC90 being listed...

Just a quick update.. been a while now since changing to Mineral 15w40 engine oil in my gearbox. Now done a few long runs and up to now all is good. Smooth positive gear change, no noise cold or hot.

Always has been an ongoing topic, I was asking the same question a while back and was told that Castrol Syntrax was the best oil to use (by a BP oil guy), but it costs about £12.50 a litre! I've never heard of any problems using mineral engine oil, so I'll be using that from now on as well.

I changed my gearbox oil on sunday, I put Millers GL3 in, it had GL4 in before I think. Only thing is that it seems to have made the gearbox worse:bang: Its now very hard to get into second gear, it sometimes goes in but I am having to slow right down to get it to engage most of the time. All of the other gears are fine. Seems very odd

Have you put a thicker oil in perhaps? 85w instead of 75w perhaps?

lewey said:

Have you put a thicker oil in perhaps? 85w instead of 75w perhaps?

Click to expand...

The GL3 is 90w, the stuff that was in before was 75w/90(managed to find out today), its odd though as the Millers GL3 is the same specification as ZC90 so it can't be too thick can it.

I run Miller's GL3. It's definitly a "thicker" feeling shift but by no means difficult. However, I think after I finish my stash of GL3 i'll start using engine oil.