Gearbox and Diff Oil Change

[Lewis's Friend]

Hi All

I'm hoping for a little information.

Firstly, what oil do people use for the gearbox and diff on an S3c (so with a LSD)?

Secondly, how does one change the oil in said areas? Do they have drains, or do you have to syringe it out? And is there a set amount they should hold, or do you just put it in until it starts to overflow the filler hole?

All tips appreciated!

[Kitchski]

I use 80w140 fully-synthetic on the LSD models. Only way to make sure you've got it all is to remove the backplate of the diff. You could try syringing it out, but you won't get it all. I guess it depends what kind of the condition the stuff that's inside is in, and whether you need to get it all out, or just most of it. Ideally you'd get it all out, but life doesn't always work like that!
Gearbox-wise the book spec is ATF, but ATF is a pretty lame gearbox oil so I use 75w90 semi-synthetic. Ford actually used to spec it back in the days of the Capri, but when people complained the gearshift was too stiff when cold, they advised filling with ATF as it's thinner. No where near as good though, and to be fair I can't say I've actually noticed a stiffer change when cold on anything other than an LT77 box when using manual gear oil over ATF.

[GadgeS3C]

It may have already been covered but just because it's an S3C doesn't mean it has an LSD - TVR innit!

[phillpot]

If it is a LSD will it be a "viscous type" ? So same oil as a standard (open) diff?

[Kitchski]

phillpot said:

If it is a LSD will it be a "viscous type" ? So same oil as a standard (open) diff?

Technically, yes you probably could just use 75w90, or even EP90 in some cases. It'd certainly be much cheaper. The 80W140 stuff is probably overkill, but worse case scenario is you've over-specced the oil. Best case scenario is that for the addition £10-£15 or so, it does a better job of protecting your diff.

[phillpot]

Kitchski said:

Technically, yes you probably could just use 75w90.

Not disagreeing with your choice, just clarifying that it won't need a "special" LSD oil



Gearbox doesn't have a drain plug so it's some sort of syphon required or you can loosen the bolts holding the extension housing to the main gearbox casing, tweak it back a millimetre or two, let oil drain and re-tighten (and fingers crossed the gasket didn't tear)!


Re-fill till it comes out the hole, ignore all that bumkem in the Steve Heath book about using bits of bent wire to measure when oil is a couple of millimetres below the hole, drop more oil will do no harm, imho

[Lewis's Friend]

Cheers for all the feedback fellas. Service is due soon, so I'll do the whole lot then.

[Kitchski]

A better question would be to find out you don't have an LSD then ask me if it's worth the hassle of retrofitting one. You'll see a grown man cry!

[Lewis's Friend]

Kitchski said:

A better question would be to find out you don't have an LSD then ask me if it's worth the hassle of retrofitting one. You'll see a grown man cry!

I am choosing to believe it does have one...!

[ATS3]

Some good info on here for a newbie to the world of TVR, thanks. My S3 is booked in for a gearbox oil change on 9 May at my local garage.

I have specified 75w90 semi-synthetic oil for the gearbox.

I'm not sure whether mine has a LSD or not, so do I still use the diff oil suggested here?

Andy