Hi all!

Just done an engine oil change, but looking to change the gearbox oil. Not sure how to go about this, as there is nothing in the haynes about it , otherwise I would be getting my hands dirty now!
The gearbox on the car is naturally noisy , so I am looking into putting a slightly thicker oil in there, instead of the recommended grade - (naughty I know) - just to quiet things down. Any help or suggestions? Thanks!

Sorry, found the part on changing the box oil, its about two sentences long (I should be shot)

Wouldn't mind advice on choosing thicker oil though...

Thicker oil will increase the pressure in the gearbox - don't think it will do much for sound deadening... it will certainly blow your seals!

For sound deadening, go for some under-carpet material - much cheaper in the long run and pretty easy to fit.

You have a 1.4/1.6? I think you should be using 2L of 80 grade gear oil for the 'box.

I always add a tube of Molyslip - as well as Slick 50 in the engine oil - belt and braces

Its the 1.6, but goes like a 1.0

Probably would be better to stick with recommendations!
I'm sure the new oil will work wonders with the box, probably hasnt seen fresh oil for a while, and would quieten things down anyway.

Might look into sound proof material, any recommendations?

Do a search for "Auto Soundproofing" in your version of Google (whatever it is) and you will no doubt come up with lots!

The most basic is a flock-like fireproof carpet that you stick under your existing carpet in the UK about £8 m2

One of the more expensive is lead sheets that stick to your firewall, door linings, etc. and you can drape over your gearbox - quiet but heavy.

Of course then theres the old garage trick of stuffing a womans stocking into the box thru the filer plug. Apparently this gets chewd up and coat inside of box with an insulating lining. However never tried it as hate to think what it does to oilsways!!! Better leave it as an old wives tale I think! There are better solutions, have you tried the Wynns additives? they have worked wonders on my 30 year old MGB box and axle You wont get rid of all the noise but will get a definite improvement a tenner well spent

you can also use engine oil like castrol GTX.this will quieten things down!!

Good synthetic engine oils can be used in gearboxes (actually recommended by one gearbox expert that I know) the advantage is less resistance in the box so it should be easier to select gears disadvantage is that the lighter oil will leave the box sounding louder. Good gear oils contain “ep” (extreme pressure) additives to help prevent the oil being squeezed from between the teeth of the gears, don’t know how engine oils fair in this area.