Gearbox oil volume

[Aaron]

General question guys,

Has anyone ever tried overfilling the gearboxes in the 126 to prolong their life?  Speaking from a previous life, this is common practice with Lada Nivas (another archaic FIAT design) to maximise the life of the bearings and stop 5th gear flogging out.  You would put 2 litres into gearbox that should only have 1.3.

My Niki's box is whiny, so I'd like to extend the life as much as possible.  Currently I've filled this to the bottom of the plug hole (about 1.1 litres) with a mixture of 20W-50 oil (as per what I understand I should be putting in) and 25% Lucas oil stabiliser.

Any thoughts?

[michaelodonnell500]

Is the whining only in first gear?
That's usually a good sign of the fatigues of a non- syncro 1st gear.
I use the same oil as you, but I don't add a stabaliser.
If the whine is present accross all gears it could suggest the oil is a bit low, but I don't know what the implications are of overfilling.

[Aaron]

Yep, so far only first gear - its about as noisy as reverse.  Mind you I've only driven it a couple of hundered metres in the last 2 months.

I remember from the test drive I did on it at purchase that there's a slow whoop whoop sound in 4th but I was thinking I'd re-evaluate that once some new tyres were put on it as the old ones have some funny wear patterns and may have been making the noise.

If it's normal and nothing terminal, I'll just persist with it and treat the box with kid gloves.  I do have another I'm planning on reconditioining for just in case but I'd like to push that out a bit.

[pumex]

If you put more than 1,1 l of oil into the gearbox it will all be gone by the rubbers that are sealing the side shafts, so it is pointless. If you have problems with the first gear only it means that mechanism of the first gea that is not synchronized is damaged (it's one of the most common damage in 126p gear boxes)

[GTMaster]

The whine in first and reverse is normal because of the straight cut gears. I don't see too much point in over filling either but it's up to you.  In the book it says 80w 90 oil for the gearbox/differential and steering mechanism.

[Aaron]

Hang on, without opening up a can of worms here, does the 126p use a different oil in the gearbox to other 126s?

Looking at the aircooled hand book here on this site, it lists the gearbox oil as FIAT ZC90.  On the next page it has an alternate list which gives equivalents to ZC90 as Cstrol GTX, Mobil 20w/50, Havoline 20W/50, etc...  Also Castrol Australia's website lists the best oil for the FSM Niki as being a 25W/50, Valvoline 50 monograde, Mobil 50 monograde and Shell haven't quite got the hang that FSM existed.

So everything prior GTMaster's comments has lead me to think 20W/50 would be correct.  Now I'm confused. </*

[GTMaster]

Didn't know that the Niki uses a different type of oil. In my book (for the FSM 126p) it says 80w 90 'Hipol' oil. I've even bought 2l (2x1l) of Agip 80w 90 gearbox oil for my 126 since i've already changed the oil in the steering mech. and will be taking off the gearbox after which i'll change the oil in it. Sorry for confusing you, just that i refered to my book (which is translated from the original Polish book.)

[pumex]

In Polish book it is also said to use 80w 90. Hipol is just a name of Polish oil So any 80w 90 should be good.

[jeffgainford]

Yep, so far only first gear - its about as noisy as reverse.  Mind you I've only driven it a couple of hundered metres in the last 2 months.

I remember from the test drive I did on it at purchase that there's a slow whoop whoop sound in 4th but I was thinking I'd re-evaluate that once some new tyres were put on it as the old ones have some funny wear patterns and may have been making the noise.

If it's normal and nothing terminal, I'll just persist with it and treat the box with kid gloves.  I do have another I'm planning on reconditioining for just in case but I'd like to push that out a bit.

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