Gear coatings on a standard box?
Turbo Mini Forums

I've just stripped down what I thought was a standard DAM 5626 gearbox and find this coating on the baulk ring contact faces of the gears.

Any ideas guys?

looks like a JKD item

Own the day

If it is there should be a part number visible.

Own the day

That was the first thing i looked for but I can't seem to see any part number anywhere on it

Looks normal to me. I've seen gears like that in boxes I've stripped. Prob as sprocket says.

If something is worth doing, it's worth doing half of.

It is definitely not discolouration. It had a very defined edge on the small end of the cone (the camera has just picker up a shiny line. The gearbox was otherwise very clean also. it is identical on all four gears.

Any more ideas?

all standard gear synchro cones have a coating of Molybdenum.

It is this Molybdenum that has discoloured, perhaps from the cocktail of chemicals seen in dirty old engine oils especially if left for some time.

To quote an extract from this document http://www.google.co.uk/url?sa=t&rct=j&q=&....49784469,d.d2k

To a great extent molybdenum and its alloys exhibit very similar corrosion behaviour, so they will not be treated separately in the following general overview. Under humidity less than 60 %, molybdenum is resistant to atmospheric corrosion. Above 60 % slight oxidation discolouring may develop. Rough surfaces are more susceptible to this than smooth ones. Regarding other aqueous media, an instability towards alkaline and oxidising substances at temperatures above 100 °C is to
be mentioned. Reactions also occur above 250 °C with oxidising gases and elements in other states. Molten glass, hydrogen, nitrogen, inert gases, molten metals and ceramic oxides hardly attack molybdenum at all, even at very high temperatures, provided they do not also contain oxidising agents.