M47 gearbox oil?

[66Lover]

Hi folks,

The gear shift on my 92' 2.3 SE is fine and it has a nice quiet 5 speed manual but recently it has been hard to engage 1st and 2nd when the car is hot.

Obviously this is likely to be the clutch dragging slightly and I've already adjusted the clutch detent plate.

But I thought I'd change the gearbox oil as well to see if this helps. People also suggest that changing the gearbox oil can give a slicker change etc etc.

But - what gearbox oil to use!

I've searched around and obviously there are many threads all over the net, all of them full disagreeing parties as to what type of oil to use.

Some say only use the original Volvo stuff, but even then there is disagreement as there seems to be several. Some say pure engine oil, some say ATF, some say MTF. Some seem to say Redline MTF is a good transmission oil although it needs changing every 30,000 miles?

So I though I'd put it the the kind folks of this forum. What do you use and where can I get myself some in the next few days?

Thanks!

[Derek UK]

You mean Redline MTL and not MTF. Generally considered better than F type ATF. 30k changes, not seen that, but changing to a different oil to what is in there now might warrant an earlier change than normal before reverting to the Volvo recommendation for change intervals. Do you intend to do lots of mileage?

[66Lover]

The car is going to become my daily driver and will be doing 10,000+ miles a year.

I hear that the original fluid was supposed to be a 'sealed for life' affair in theory but like the idea that I could be getting smoother shifts and that new oil could improve my 1st and 2nd gear problems, several people online seem to suggest a change of oil has cured various maladies present on their cars.

So just wondering if anybody has changed their gearbox oil, what did they use and did they find it improved matters in any way?

[Clifford Pope]

I think if you search here, on line and on Brickboard you will find every shade of opinion argued for.
Some say stick strictly to the Volvo recommendation.
Some say OK, but remember that was for a new box, not one that may now have done a high mileage,
Some say ATF is better because it is thinner than ordinary gear oil, so less friction, others say thicker oil is better after a high mileage because it stays in place rather than being squeezed out, so lubricates better and is quieter.
Some say the thinner oil was just a marketing ploy to get a slightly better mpg figure, some say yes but that was at the expense of shorter life.

All I can add to the debate is that I once had a M46 overdrive box which despite using the recommended ATF started to slip in overdrive at 200,000 miles.
I swapped to EP80 semi-synthetic gear oil and the overdrive was transformed - much quicker to engage and no slipping. The box was still in perfect order when I scrapped the car for other reasons after a further 200,000+ miles.

So take your pick.

[66Lover]

Thanks Clifford. Yes, that does seem to be about the length and breadth of it. Heard of somebody using EP90 recently as well. I think effectively what ever you use it isn't going to do any harm and there is a good chance it is better than the stuff that has been in there for 200,000 miles.

Anybody else got any first hand experience?

Graham

[Derek UK]

Don't use EP90 or EP anything. That is a hypoid oil for use in axles where gears have a wiping action.

[Clifford Pope]

Originally Posted by Derek UK

Don't use EP90 or EP anything. That is a hypoid oil for use in axles where gears have a wiping action.

All manual gearboxes have hypoid gear wheels - the teeth are cut at a slant and there is a wiping action as they slide over each other.
No modern gearboxes have purely straight-cut gears, except for reverse, and older vehicles having non-synchromesh 1st gear.

ATF oil usually (formulations vary) has EP properties, it's just not called EP.
If it didn't it wouldn't be suitable for use in a manual gearbox with hypoid-cut gears.