Gearbox Oil whats your thoughts?

[looseunit225]

hey guys

just woundering what you guys run for oil in your gear boxes?

i've been running mercury racing stuff in my OMC lightning gear box but i have been told a few people run ATF (auto fluid) in there gearboxes!

i know from when i used to race my track car we used to run ATF in the gearbox and we never had a drama your input would be very apprciated!

cheers

[850cc racer]

atf!! :eek: not when a little water might get in there!!.. i use anglom oil :cool:
the mercury stuff is good too.. i find anglom to be better.. u need to be using something that will mix with the water, that atf wont. where as anglom oil and the merc hp stuff will :cool:

[looseunit225]

but you shouldnt be getting water in there in the first place!

[850cc racer]

this is true, it will happen though, and im my case running small gearboxes big props will soon slog out a gearbox :( i change mine after every race meet.

[looseunit225]

i change my oil after every practice and every race never found any water in it yet!

[Mark75H]

I'd steer away from atf for sure.

I use synthetic. On screamandfly.com there is a member in the US who ships their synthetic to screamandfly members with no shipping charges.

I used to change my oil after every weekend of racing, but am no longer seeing metal or any evidence of breakdown of the oil and am going longer.

If the oil you are using is protecting your bearings and gears, staying in the case and not having water problems ... it is good enough.

[billy-jay]

Ran EP for long time and used ATF and never had any problems

[Don Muncie]

ATF is ran in automatic transmissions ONLY!

It also makes a great cleaner for pre-assembly of engines and gearcases. You'll be amazed as to how much crap is still in those parts even after they go threw the wash. Here's a test, think those cylinder walls are clean? Before you assemble the engine, take a white paper towel, add some ATF to it and scrub away..I think you might have this expression:eek:

Mercury synthetic is very hard to beat! I make kind of a witches brew outa that stuff by adding Lynch Extreme Pressure Lube to it. I use an aonce of that stuff to every 8 oz's of gear lube. Ever since I started doing this, my commercial guys haven't found a way to destroy their drive units yet.

As far as racng units go, I use that same Lynch stuff to 105 Luberplate at the same ratio and have had GREAT success with that as well.

If anyone is interested in this Lynch stuff, email me at <mrbill@pns.com> and I will get you contact info direct to Gary Lynch.

[looseunit225]

its just that i replace the gearbox oil so frequently and the oil isnt exactly cheap but i can get ATF and Hydraulic fluids and other certain oils for free threw work!

[Jakob77]

Alisyn...

[jerry book]

We have been running Mercury hi performance in #6 speedmasters and have had only 1 failure in 7 years. The case that failed had 50-60 hours on it.

[Danny Pigott]

OMC High Vis. with STP mixed in it. This is an old stand by. i used it in merc D units Konig units Yamato units. We used this for many years an never had a problem. I have got a merc. unit under a 3 cyl. omc FEH an it has not failed.Botton line is if you have got a good unit it will last, if its not it will fail.As far as speed gain i don't think it will make much differnce the water pump will put more drag on the unit than the oil can make up for other than the pumpless units. In the 50's my dad had merc. units converted to pumpless.

[Phil McDaniel]

I've been running the same thing Danny's running except I add some molybdenum disulfied. Same gears in a "D" unit since "81 and they haven't even laped in yet. Phil