Mixing gearbox oil brands - problem?

willk · 29 January 2013, 15:54

An odd one - a friend has a brand new (potentially non-PDIed) Tohatsu 9.8 2T and the gearbox is not quite full of oil - is it OK to top this unknown oil up with another brand? I seem to recall something about some oils reacting - can't remember...

Thanks in advance!

simsy · 29 January 2013, 15:59

I believe this is possible, but unlikely with hypoid oil. Also, most car gearbox oil means the required spec, and is cheaper than the marine branded stuff.

Nos4r2 · 29 January 2013, 16:34

DONT mix with car hypoid if it hasn't even been PDI'd yet!

willk · 29 January 2013, 16:51

What is car hypoid and how did it get into my thread?

The gearbox has what was shipped from Tohatsu (I presume) and the oil I have is Mercury...

Did I use the word gearbox incorrectly in a sentence?

I probably mean Marine Gear Oil

Dirk Diggler · 29 January 2013, 17:23

As the amount the box holds is tiny, I'd dump the lot and start again.

Nos4r2 · 29 January 2013, 17:44

Quote:

Originally Posted by Dirk Diggler

As the amount the box holds is tiny, I'd dump the lot and start again.

Seconded. You'll lose a load in trying to top it up anyway.

willk · 29 January 2013, 17:46

Quote:

Originally Posted by Dirk Diggler

As the amount the box holds is tiny, I'd dump the lot and start again.

Yes - in the absence of a positive response, this would be my personal choice as it is the safest. I was more curious than anything and it would have been a waste to dump it if it was OK to use.

Mollers · 29 January 2013, 18:04

Quote:

Originally Posted by willk

..it would have been a waste to dump it if it was OK to use.

F'k, is it that bad over there?

willk · 29 January 2013, 18:15

Quote:

Originally Posted by Mollers

F'k, is it that bad over there?

S'always lean in the willk household

In this case I happen to be in possession of the oil but not the engine, so I'm potentially exposed to being expected to make some uncharacteristically generous gesture...

Mollers · 29 January 2013, 18:41

Quote:

Originally Posted by willk

S'always lean in the willk household

In this case I happen to be in possession of the oil but not the engine, so I'm potentially exposed to being expected to make some uncharacteristically generous gesture...

Ah, the trick there, is to quietly decant the oil into a pickled onion jar to throw him off the scent.

If he should happen to have a bit of Welsh in him or be a particularly tricky f'er, I'd chuck in a couple of onions in for good measure.

willk · 29 January 2013, 19:03

Excellent plan - he hates onions!

Mollers · 29 January 2013, 19:08

Quote:

Originally Posted by willk

Excellent plan - he hates onions!

Don't forget to save the vinegar for his box.

Ribochet · 29 January 2013, 19:15

Quote:

Originally Posted by Dirk Diggler

As the amount the box holds is tiny, I'd dump the lot and start again.

+1 - if in doubt

However this issue really only occurs when it comes to mixing synthetic and mineral oils.

willk · 29 January 2013, 19:23

Quote:

Originally Posted by Mollers

Don't forget to save the vinegar for his box.

I'm gonna pretend to not understand that and hope no-one else noticed

tonymac · 29 January 2013, 19:36

Quote:

Originally Posted by willk

I'm gonna pretend to not understand that and hope no-one else noticed

I noticed!!!

uncle al · 30 January 2013, 17:35

NEVER EVER use automotive gear oil in an outboard motor! Because marine gear oil has been made so that if water gets into the g/h the oil will keep the water aqway from the gears and bearings , thats the thery anyway.It is also not advisable to mix oils either gear,engine or any oils.

simsy · 31 January 2013, 17:46

Hypoid is the type of gear in the outboard gearbox. Car hyoid oil seems to meet all the requirements for some marine use, including the water mixing requirements.. I.e. it readly mixes with water to form an emulsion rather than seperating. The spec On the water ingress marine oils is covered by the automotive oil specs in many cases.

willk · 02 February 2013, 20:00

So anyway, that all worked out very well. There was VERY little oil in the box, so charged with Quicksilver and away to the tank where she sprang to life in short order. After that it was down to the sea where it got christened on the back of a friends SIB. It did surprisingly well for a long shaft. Another 8 hours on 25:1 and a gear oil change and she'll be right.

A very nice day on the water today in Deep Six - cracking start to 2013.

Cheers donegaldan!

Alan Priddy · 02 February 2013, 21:25

Quote:

Originally Posted by uncle al

NEVER EVER use automotive gear oil in an outboard motor! Because marine gear oil has been made so that if water gets into the g/h the oil will keep the water aqway from the gears and bearings , thats the thery anyway.It is also not advisable to mix oils either gear,engine or any oils.

Might have to disagree with this. To my knowledge there isn't an oil made that will still work when it is contaminated with water. It's the specification of the oil that is important not the brand name. In a clutched unit the destruction is caused by the water contaminated oil generating steam inside which lifts the bonding elements Alan P

willk · 02 February 2013, 21:37

Quote:

Originally Posted by Alan Priddy

It's the specification of the oil that is important not the brand name.

Like a Tesco's 100% Beefburger or a Sainsbury's 100% Beefburger?