Gearbox Oil

tim leech · Post by **tim leech** » Fri Jan 05, 2007 11:33 am

Im going to be have fitted 2 new driveshafts soon, I will of course change the oil seals and Im told I will loose the gearbox oil in doing so, what kin dof oil is best? my box on my car is light and slick so I want to keep it that way!

ed_straker · Post by **ed_straker** » Fri Jan 05, 2007 3:09 pm

It should stick to the API-GL4 specifications. Castrol has some TAF-X (?!) should be 80w/90 about 2 Liters i think. You can fill it up until oil comes out again, that will do the trick.

kriskarrera · Post by **kriskarrera** » Fri Jan 05, 2007 4:42 pm

Isn't it best to stick with the original viscosity, i.e 75w80?

Timmo · Post by **Timmo** » Fri Jan 05, 2007 4:59 pm

if you have a good box then 75-90 is good stuff for them! there is a special blend for pug boxes! cant remember what its called now though! luke told me ages ago! loL!
but if your syncros are a bit iffy then stick to a thicker oil (lower number!) mine has 2l of ep80 in it as the synchros are a bit bad when hot downchanging into 3rd! but ht ethick oil keeps it sweet!

tim leech · Post by **tim leech** » Fri Jan 05, 2007 10:16 pm

My box is spot on, no crunches, even in reverse, finger light too.

Post by **Vanny** » Fri Jan 05, 2007 10:26 pm

i get nastyness going from 2nd to third, and put 1.8 litres of FUCHS 75w 90 cos it's all that th elocal supplier seem to sell. Anyone know more about this Nulon stuff? Heard alsorts of raving about it, but what is it and what exactly does it do?

Post by **Toddman** » Sat Jan 06, 2007 4:04 pm

PSA boxes are renowned for being picky about what oil they like.
As said if the box is in good order best to stick to OR spec as the synchros rely on viscous drag.
Even with the xsaras citroen had to blend a few specials just to help with the slow synchro

Cheers
Luke

tim leech · Post by **tim leech** » Sat Jan 06, 2007 6:37 pm

So what should I use, I dont mind if I have to by genuine stuff as lomg as its right.

kriskarrera · Post by **kriskarrera** » Sat Jan 06, 2007 7:50 pm

the 75w80 oil from GSF: £3.50 a litre (Or £9.50 from Pug - exactly same stuff)

AlanS · Post by **AlanS** » Mon Jan 08, 2007 10:07 pm

I've always had best results with a straight Castrol 80 with the Nulon in it.
It seems that according to Gabor (CitBX DIY pages) that synthetics don't behave in these older boxes and Anders tracked that down to the type of material the synchros were made from. It seems it works in later BE3s but not in our age bracket ones.
I've also noticed that synths seem to get up into the 90s as their upper end figure and again anything over 80 seems to be inviting trouble so that may be the issue more so than the synchro material.
The oil we get here that is very compatable is "Castrol VMX80" but IIRC, it is marketed over there but under a slightly different guise, I would expect possibly due to the climatic difference, it could contain slightly different additives. A check of Castrols website should clarify which one is its equivalent.

Alan S

Post by **Vanny** » Mon Jan 08, 2007 11:35 pm

tec docs for the Castrol VMX80 can be found
At this link

tim leech · Post by **tim leech** » Tue Jan 09, 2007 12:33 pm

None of that makes any sense to me lol as im no teccy but I will get some of that gear oil from GSF then!

Thanks for all the input!

AlanS · Post by **AlanS** » Tue Jan 09, 2007 9:13 pm

tim leech wrote:None of that makes any sense to me lol as im no teccy but I will get some of that gear oil from GSF then!

Thanks for all the input!

In straight talk; don't use synthetic gear oil and if it gets above an 80 rating, it's going to give you problems with notchy changes.

lan S

RobC · Post by **RobC** » Wed Jan 10, 2007 10:16 am

funny, every time i've used non-synthetic oil my gearbox has got very upset.

maybe it depends on the box's history?

i.e. if it's always had synthetic, stick with it, and vice-versa...

currently got the Total stuff that Citroen recommend in mine, and it's smooth as a whistle (well, a 160,000 mile whistle anyway).

AlanS · Post by **AlanS** » Wed Jan 10, 2007 11:46 am

What grade though Rob?

Where I think most get stuffed up is they buy the synthetic without looking at the numbers and suddenly wonder why it all gets clicky, although you'd hardly think Gabor would get caught iout with that.

A couple of years ago there was a long winded debate on this and it was eventually decided that the later gearboxes seemed capable of handling the synthetic (post 1993 from memory) but anything before that it was unheard of it doing anything but causing shifting problems.
I'va also had series 2 Peugeot 405 owners out here also claim that their boxes are supposed to have the synth in them, yet my 94 Xantia had it in (unbeknowns to me at the time but discovered later when the service records arrived) and I went VMX80 + G70 with immediate improvement.

Alan S

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