ATF used in 6 Speed Box and Diff

[Notsohotcams140]

On the plate in the engine bay it says Ep80 for the gearbox and EP90 for the diff. 

Currently they both have ATF in them. The gearbox is weeping fluid slightly when warm but would this stop if EP80 was in the box rather than ATF?

i think it's got a ZF diff in it. 

I am planning to put the fluids in named on the plate under the bonnet, what's the benefit of ATF in there instead?

[simonpa]

How do you know it has ATF in there?

I've seen posts about putting ATF with lower viscosity to help with cold running and maybe save a few pence on fuel costs - don't think it is recommended though, especially in a diff, which generally needs more shock resistance.
There are normally addidtives in ATF, which probably wouldn't help a LSD.

I'd change it to recommended fluids, probably with an intermediate mini-flush to clear it out...

Where is the 'box weeping?
Changing the speedo seal is easy - the prop seal, less so.
I've seen oil additives that say they swell seals to stop leaks, but they certainly wouldn't be a good idea on a gearbox.

 

[Notsohotcams140]

The previous owner told me that is what he put in it. He was advised to by a fellow club member. 

I haven't been able to fully investigate exactly which seal/seals is/are leaking however it's dripping from the front of the gearbox but this is the lowest point and the bracket at the back of the gearbox is damp to touch. 

[oldbutnotslow]

This is a new one on me Using ATF is something that I have never come across  in manual gearboxes and difs.

If it were me I would do as Simon has suggested Drain it Flush it and fill it with the recommended EP oil

Incidentally ATF is not an oil but a mixture of various chemical compounds containing a large number of additives. It must fulfill many specifications.  ATFs are colored (red or green) to distinguish them from other liquids used in a vehicle. Common ATFs  are DEXRON (General Motors) or MERCON (Ford).

[OliverSedlacek]

The rationale for using ATF is that its lower viscosity reduces power losses in the transmission, but I was strongly advised against it by BGH when I bought a gearbox off them. Using anything other than the recommended grade reduces lifetime, which was their arguement against it.

LSDs are a whole different ball game, and I think it depends very much on the LSD technology as to what you should put in it. VC types presumably run special fluid, and plate types like the Salisbury are fussy because they depend on friction plates.

[elie boone]

ATF in a gearbox should be fine, i wouldn'd use it in a diff, especially with a ZF i would use something like Castrol 373. BGH may not have tested ATF in their boxes so it's logic the will not recomend it.

[Mark Durrant]

I recommend Castrol B373 for the LSD

[Nigel Riches]

Having trouble with the tablet here tonight. 

 there's a thread near here about using EP90 GL4 diff oil posted by Titanium7, I managed, after a struggle, to post some links, they may be of interest to you, 

Regards, Nigel.