Going to change the gear oil on my 1970 Fiat 850.
Does anyone know if there is some form of seal on the drain plug?

I recently topped up the oil in the box and didn't notice a seal washer on the filler nut. Didn't do a full change so I cant say about the drain nut.

Before you drain it make sure you can open the filler nut.....both are located on the left side of the car one on top of the other just in front of the drive shaft.

Gav

Hi

both the fill and drain are normally taper fit, a 17mm ring spanner is your best bet and if you need a bit more leverage then hook the ring of another spanner into the open end of the 17mm spanner.

if you get one of the 1 litre bottles with the fill tube end, then there is just a small space under the floor to fit it in while it drains the oil into the gear box.

Tim

I seem to recall that the gearbox filler plug on (at least some of) the 850's was a 13mm square.
If you don't have a 13mm square socket , and you can't loosen it with a 13mm open-end spanner, iirc a 15mm bi-hex (12 point) socket will fit.

Al.

Just did the oil change on the gearbox.
It is taper fit filler and drain plug, a 17mm ring spanner does the trick!

Thanks for all responses!