Oil/Tar Removal

Soak with wintergreen oil, let it sit till the oil/tar starts to loosen then work with a scraper and brushes.

I have also heard of people soaking this type of mess in kerosene. But be patient it takes a while to eat through this stuff.

Hope this helps.

Warm it up, and let gravity do the work.

Spread butter on on it, let it sit a short while, rub it off.

No joke, I've use it for decades to get tar off my cars, it is the gentlest thing for that job. Try a small area so you don't waste butter if your goo is too dense.

Interesting. Send that one to Myth Busters!

Warm diesel fuel (or bacon fat!!).

Mind you, warm can be taken for a factor of imagination. I had a friend once ask me how to get a dump truck load of hardened asphalt out of one of the transfer conveyors used for paving highways, and gave him the same answer. The next week he told me it worked great. On further inquiry, it emerged that he was filling a metal pail with diesel, heating it with a propane roofing torch until it caught fire and then dropping a lid on it. He then proceeded to remove the lid and pour it over the mass of asphalt. BTW, did I mention this was all being done up on a scissor lift, as these things are seriously big? Just wish I had a picture for Caption This.......!

Straight out of the Darwin Awards Cookbook!

I have used lard or Crisco with the same results you mentioned

This oil oil and tar residue is inside the gear box?

If it is. It's not tar but grease. A lot of those old gear boxes the gears used grease as lubricant. Heating it up some will get it to soften enough to scrap the bulk of it out.

Then soak the rest in a solvent. Mineral spirits should do. MEK if you need something more aggressive.

Yes, it is inside the gear box. Access is limited but what I can see is this thick tarry substance, caked on the inside walls of the casing. The opening into the box is 3" x 2" but what I have managed to get out has the consistancy of rich cheddar cheese. At the minute, everything is seized up solid so to dismantle it is a bi of a challenge.....! Thanks, Norm.

Take a torch to a lump of what you already got out and see if you can get it to flow.

If so turn it up with the opening down and start heating the case.

Most likely will have to replace the seals anyway. Because of their age.

Seems like a good idea. No dangerous/flammable solvents involved - other than what's already there.

GA. Most shops will want the majority of the old grease removed before "Hot tanking" After the Hot tank it's imperative that everything is thoroughly rinsed and re oiled and or greased. Hot tank solutions are extremely caustic, so you also need to remove any seals or plan on replacing them before putting the gear box back in service

Also, make sure the case isn't aluminum!!

Hot tanking will eat aluminum, zinc, babbit and can be hard on brass. It's best for steel and cast iron.

Lots of great answers and or suggestions so I will add baking soda.. bring 1 gal.of water to a boil and add a liter of baking soda mix well and pour in the gear box and let sit for a day and see what happens. Cheap and possible cleaner I know it works on many things that seem almost impossible to clean. This is similar to hot tank ( caustic soda) but more gentle.

I have had occasion to disassemble a few old gearboxes. Some looked exactly as you described. Dried up gear lube, the type found in manual transmissions. After 20 years or so, depending on the climate in your area, this is whats left. And I should add there are those who would add all sorts of things to use as fluid in a pinch. Out here in the desert everything gets cooked by the sun and ends up like your description. Diesel would be my first choice.

Some of the citrus oil products also have amazing cleaning qualities in heavy oil and tar like substances. We used them in the oil patch with mixed but mostly good results.

WD-40

Steam cleaning should the trick! Exposing the gunk to a source of saturated steam I think will make your job easier... Just stay away, or enclosing it is a must for personal safety...

Good luck!

Try dry type Drano or Lye and water solution.

Let it soak for several days,the rinse thoroughly.

I cleaned an oil pan from a 1948 Ferguson tractor,that had never been removed,so the gunk in the bottom was over 60 years old,and impossible to scrape off. Carb cleaner,brake cleaner,WD40,etc. were useless.

I put dish-washing-machine tablet and water,then put it on a gas burner till it boiled,and reduced heat to maintain a simmer.

(Add salt and pepper to taste).

After several hours of simmering, when I dumped the liquid, it was as clean as a new oil pan,only slightly darker metal.

I don't think anyone has mentioned acetone and lacquer thinner.

I haven't tackled anything this tough, but I tend to start with something mild like kerosene, then escalate the potency. Lacquer thinner, acetone, etc. Only had to go to MEK with some very old tire paint. It took acetone to remove gasoline residue.

Heat will help most anything work faster, but some solvents are extremely flammable, so be careful.

Never ever use petrol/Gas. Its simply too dangerous.

There are plenty of other answers here that should work, but take your time....

Best of luck

Well lads, the saga continues. I stuck it on a gas ring and cooked it..! Which charred everything, then gave it a good poke and the suff started falling out. Then I proceeded to pull it down. The bearings on the worm wheel are tapered and absolutely bunged up, I've manage to get the cup off one side and that's as far as I've got. Talk about a challenge, any way I will persevere. Norm.

Thanks for the update! Hope the rest goes well.