How to identify gear oils, and what can be mixed with what?

[NitroDann]

Hey guys.

My new car sounds a little bit gearboxy or diffy...

Probably a dieing diff, based on my previous dead 4 diffs.

Anyways, I must have a broken lower shift boot cos I can smell gearbox fluid. Tonight I will check gearbox and diff levels when I get home.

Im looking at people like magna blue for this one, can I mix my just drained 4000km old fluid I had in my 6 speed to this gearbox to top it up? How do I identify if I can or cant?

Thanks,
Dann

[gslender]

I was talking to Jason at mx5plus and he was fine with reusing recently used gearbox oil assuming it didn't have much iron filings it.

[NitroDann]

Yeah Im fine with that, but I know some gear oils do silly things when mixed, wrong oils can basically lock a gearbox up and needs huge flushes.

Not sure how to identify whether I can mix fluids.

Thanks,
Dann

[manga_blue]

Dann, I don't know if you can mix them or not. Basically I never do it. I've found my gearboxes have been so sensitive about oils over the years that I just want to keep it simple. If an oil doesn't work then I drain it, store it, filter it and use it for something less fussy. Good oils are usually expensive, so I don't want to risk buggaring up a good batch by trying to save a few dollars.

If I was draining a sump full of freshish oil that I know works in my car then once again I'd store it, let the metal dust sediment out, filter it and re-use it, if necessary topping it up with new oil of exactly the same brand and grade.

I reckon a quality gear oil should be good for 20,000kms of the sort of driving we do.

[NitroDann]

If its low Im gonna mix some fluid and give a review

Dann

[deviant]

Is there anything that could be observed by just sitting a couple of oils in a jam jar and letting it sit a while? I guess the heat, churning and pressures might make the difference.

[ak_perth]

Not another "oil" thread!!!!!!

Just kidding, sorry Dann, couldn't resist saying that!

[NitroDann]

So i took what was left in the pan on the floor from my 6 speed and filtered it though a rag and put it in the 5 speed, it took more than half a litre. It was at least 3 inches below full.

Anyways it sounds better now.

Ill check the diff tomorrow.

Gearshift is fine.

I mixed red with yellow.... Ill tell everyone what the red was when I find the bottle.

Dann

[project.r.racing]

Normally not an issue with mixing fluids. A very small precentage of fluids may not like being mixed together. Hence the general rule is not to mix at all. Don't play with fire unless you have to.

One of the cars I own has a FWD box with clutch plate LSD. The LSD is not seperate to the gearbox, so needs all the one fluid. So I just use 2L of tranny fluid and 1L of LSD fluid. Tried and 50/50 blend once, couldn't get it into 1st ,2nd and 3rd gear changes where impossible with puting the car into neutral and shifting at idle rpms.

[Mr Morlock]

I reckon Manga and Proj rr are right. For those following these Q&A's bear in mind apart from talking to your local mechanic the oil co Technical lines also give you advice on the phone. I got some useful phone advice recently about Shell and Castrol and that was to my benefit.

[NitroDann]

Yeah it isnt a big deal or long term, just for a week. I wasnt missing oit on a thursday night mountain run in my new car and was wondering about mixing fluids, which we all know is not ideal, but I wanted to know if there was a way to identify what can and cannot be mixed.

Anyways, the red stuff was nulon 80w90.

I had a litre of redline on hand but wasnt going to waste it in a 5 speed.

Dann

[Aussie Stig]

There is a group buy with some Ford Synth stuff from the states.

Will be really interested in how that turns out. Maybe the uber oil we have been waiting for.