What Gearbox oil (Astra Manual Transmission)?

Go with EP90 preferably. EP80 if you can't get 90.

Autodata says 80w !! As it is red and modern, then I would put in MTX75 oil (any car shop should have this) which will be perfectly safe in any modern ordinary manual gearbox.

mrcheerful

Most gear oil used to be red.

Thanks everyone for the feedback on this.

Next question assuming what was already in the box was MTX75 oil and not EP80/90 as it should have been, and obviously their was no way of knowing this until I topped the box up, will it be ok to leave the MTX75 and half litre of EP80 that I put in or will the mix of oils be a problem.

The trouble is I am sure I can now hear the odd strange noise coming from the box.

ep oil should not be used unless specified as it is not good for certain bearings. that said, I would be surprised if it makes any real difference. the question is "why was the oil low? and how low has it been before?"

mrcheerful

mrcheerful

The problem I have is that EP oil is specified so how did the MTX75? get in there. I have no idea why it was low, their are no leaks, I assume either it was undefiled or after 77000 miles some has evaporated (if that's possible with oil) or it has a tiny undetectable leak

Yes. 75w/80 and MTX75 or MT94 are all near enough the same viscosity and some MT oils are various shades of red.

Huw

Huw

Really? Not most of the ones I know of. In fact very few that I know of even going way back to the 60's.

Huw

How ineed? Maybe the oil was changed due to a diligent owner or service centre or it has been dimantled to facilitate a repair at some point in its history.

I have no idea why it was low, their are no leaks, I assume either

Or it is only very marginally and trivially low in oil and not worth topping up?

Huw

I was unfortunately able to top it up with about a half litre of oil.

Now I am going to have to drain the box and refill it.

But what should I refill it with? EP80/90 as the books say or TMX as was already in it.