Gear Box Oil

[Angle Grinder]

Out of interest, which Gearbox oils are other Flavia owners using?

I have been using Penrite GB40 for the last few years as it doesn't have any nasty additives, but it is probably a thicker oil than I should be using.

A specialist suggested Millers Oils classic EP80w90 GL4 gear oil, but I'd be interested in other people's experiences.

[lancialulu]

Castrol ST90 is Lancia approved gearbox oil which I have used previously but I am going to use fully synthetic Mobil 1 SCH 75-90w recommended by folk in Norfolk.

[peterbaker]

Expanding the subject: Do any owners use an additive in their Flavia gearbox?

[roddy]

In a Fulvia and Flavia you MUST use a GL5 gear oil.  GL4 is for in-line gearboxes or those on the end of transverse engines.  A Flavia and Fulvia with is bevel final drive using the same gearbox oil, it has to have 'hypoid' high pressure characteristics akin to the old Hypoy 90 originally used.  The only downside of using a full synthetic 75/90 is an increased noise as the thinner oil does not have the same deadening effect, but the considerable benefits outway this aspect.

As Tim suggests, Mobil SHC is good, as is Redline.

Regards - Roddy

[lancialulu]

Roddy is quite correct re ST90 which is not an EP / GL5 so CANNOT be used for Fulvia or Flavia but only in gearboxes that have seperate differential / final drive oil.... It is great for Appia/Aprilia etc.

[lancialulu]

This thread reminded me I still had to do a gearbox oil change as part of my Vignale mechanical overhaul. I had consciously waited till the car was back on the road so I could see what the gearbox was like, and also to get the oil hot before the change.

Well I saw I had 2.5l of SCH 70-90 Mobil gear oil on the shelf so a 12 mile drive and drain (both drain plugs) was done. The oil that came out was not really contaminated or black but I guess it had not been changed since the car was new or many years ago as I could not budge the dipstick....Working from under the car I tapped it free and put in 2.4l (always some old oil left) up to the full mark leaving it to find is level between the gearbox and final drive compartments before measuring.

A run round the block confirmed a silent gearbox and possibly an easier gear change - not that it was bad before....

[Angle Grinder]

Some conflicting opinions here. According to the Flavia Consortium website you don't want to use a GL5 oil. It is quite specific about this.http://www.flavia2000consortium.org.uk/Technical/techhome.html

"Gearbox.  ALL.  (except those vehicles fitted with the big 4-speed gearbox; e.g. the Flavia 2000LX berlina and the the Flavia 2000 coupé - see note 21 below)  If you check in the owner's handbook, then you will see that Lancia & C specified oils such as Esso GX90 and Mobilube HD90.  These are your good old-fashioned  90 grade "light" hypoid oils (service grade GL4 or less), not these thin 75/90EP GL5 oils that are used today.  Do not use a synthetic gear oil, but obtain a similar SAE90 oil from a classic car oil specialist such as Morris's of Shrewsbury, or Millers, or Penrite for example.  These may be expensive, but do last a very long time.  Synthetic oils will cause damage."

I'm told that the originally Mobilube GX90 and Esso GX90 (as recommended in the Flavia owner's manual) is the equivalent of today's Castrol EP90 (GL4) and Millers Classic Pistoneeze Gear Oil 80w90.

[Brian Long]

Some Flavias share the differential oil and the gearbox oil. Others e.g. Flavia 2000 coupe use gear oil in the gearbox and EP (hypoid oil) in the differential. Separate 'chambers' with individual drain and filler plugs.
Conventional wisdom seems to discourage synthetic oils in these older gearboxes/differentials. Classic oils are available and are a closer equivalent to the originally specified oils.

[lancialulu]

Well there's the thing. I have been running 2 Fulvias used hard and covered 30,000 miles between them and both have Mobil SCH 75/90 fully synthetic oil. According to Mobil's data this oil meets both GL4 and GL5 specifications but not in the old sulphur additive way that causes problems to soft brass material.

I may be wrong but the Flavia 815 4 speed gear box is the same configuration as the Fulvia so that basis I am happy with my choice. I can only say so far my 815 Flavia has responded well to this and a thrash up the A12 to my trimmers was very quiet and coming home I noted the 1st sychro worked well and quietly....

For me fully synthetic is fill and forget.

[bobhenry999]

Blimey, this is getting confusing !

I am about to do my annual engine oil and filter and gearbox oil change.

Normally I just use EP90 in mine as it is an early car with the gearbox and final drive sharing the oil, but Tim`s experiences of using a modern synthetic oil seems to go against the usual recommendations, yet he is very happy with how his Vignale performs with it, so now I don`t know which way to go !

Bob

[Angle Grinder]

Ditto....

[lancialulu]

Over the years oil companies have found modern additives that replace the sulphur based additive. This sulphur based additive is a problem for soft metals such as brass found in gearboxes. GL4 has a lower sulphur based additive and gives a lower extreme pressure rating than GL5. You need this pressure rating as a minimum to protect the wear surfaces in the differential. GL5 would give a better protection. Now here is the rub. The sulphur based additive combines the the phosphorous additive to form a sacrificial layer on high pressure areas such as the crown wheel in the differential. It also forms this layer on anything that is subject to pressure such as syncro rings and bronze bearings. The sacrificial layer on steel microscopically peels away as it wears, but on softer material it takes a few microns of the soft material with it over time, leading to gearbox failure, noise etc.

So there you have it. Modern oils have been developed so that gearboxes run for ever. Which would you like??

If you want to read up as I did then see

http://www.widman.biz/uploads/Transaxle_oil.pdf

Tim

[peterbaker]

Interesting: as my Flavia is very early production would I be right in assuming it has just one drain plug?

[lancialulu]

Interesting: as my Flavia is very early production would I be right in assuming it has just one drain plug?

All 815 (first series ) flavias have a single drain plug according to the parts manual...

[peterbaker]

Ta.