Thread: Shellac Like Gum seized gearbox

Hello All,

Has anyone worked on either engine or gearbox and found it gummed up as if someone had poured litres of shellac into and then the shellac had hardened? Subsequently, the gearbox was seized.

I have been meaning to post about the state I found my 2A ambulance's gearbox it. It was seized. Earlier, I had pulled out the dip stick in the motor and I drew out a nice emulsified coating of yoghurt. Apparently some water had found its way into the sump a long time ago. I disconnected the gearbox from the motor and lifted it out of the vehicle. When I had the gearbox on the ground I found that the front shaft would not turn when the gear stick was in neutral. Nothing happened - it was stuck solid. Combined with my observations of the oil in the engine with the shaft in the gearbox not being able to turn, I was not feeling particularly optimistic about what state the gearbox's internals would look like when I started to disassemble it.

Instead finding lots of emulsified gearbox oil I saw that it was like generations of shellac beetles had been having a very productive time inside there. Everything was coated in the brown resinous shellac like gum. Once this gum was removed it revealed that the gear teeth were in perfect condition. I was expecting rusted away teeth. Whatever the gummy resin was - it worked better than Cosmoline. What had caused the front shaft to fail to turn was how all the gears were gummed together. It just meant that I had to disassemble the whole internal parts of the gearbox and soak the parts in petrol to remove the gum.

I know how people take the rocker or tappet covers off motors and they exclaim how the engine has the appearance of a lacquered finish and how this is a tell-tale sign that the engine was not properly maintained. Well, the 2A's gearbox looked like either someone had poured shellac into it until the gearbox was almost full, or it had been left soaking inside a vat of liquid shellac. Then it was left for years to dry into a gum. Has anyone else encountered a gummed up gearbox? Don't get me wrong - I was really happy to find that the gearbox was not a completely rusted up lump of metal. Finding a gummed up gearbox does tend to leave one feeling very curious though!

By the way - the 2A Ambulance's motor is also seized. I am hoping that the same phenomena has occurred inside the motor and that only the oil in the sump has emulsified. Yes, you can only push a sense of optimism so far. Hello delusions...

The gearbox parts have been sprayed with lanolin and are in a big bin that is sitting on a tray placed over the legs of the engine stand that the ambulance's engine is mounted to. I figure I will reassemble the gearbox before investigating the engine more closely. I have found that having too many things pulled apart at the same time is not very conducive to forward progress. For example, I will need to backtrack a bit on some earlier parts of the project to get them squared away before I take on any new challenges within the restoration.

Since it has been quite sometime since I worked on the ambulance's gearbox I say 'Thank God' for people like Steam Wally from the UK, and Mr Crocker from New Zealand, who have put out some really good youTube videos about how to disassemble and assemble Series gearboxes! Otherwise I would be very stumped... stymied and other words that relate to the inability to make any forward progress. Oh, back then I did not take photographs and videos of the tear-down process. I have since learnt the advantages of taking happy snaps as consequence of how I formerly used to learn things ... the hard way.

Kind regards
Lionel

yep, cooked oil left to sit or oil thats been washed down with a thinners thats since evaporated after wrecking the oils properties IT could have also been the wrong oil, some vege oils go that way..