using motor oil in manual transmissions?

[elvin331]

What's your take on using motor oil in manual trannys vs recommended MTF?
This seems to be an interesting discussion!!!

[jeffcoslacker]

Not sure what you mean.

Some spec gear oil, some spec motor oil. A few even spec ATF. They all have different properties, and are not interchangeable....you'd best use what it calls for.

[G.A.S.]

Yea, what jeff said.
there is no reason to use anything other than what the manufacturer recomends .
Oil is not oil my friend, I deal with bio hydro fluids, synthetic oils and fluids and everything down to the universal traction fluid on a daily basis in the equipment I maintain. You could cause damage to anything right down to a 20.00 seal.
Why are you asking?

[jeffcoslacker]

A lot of Honda and other make's MTX's spec 10W40 motor oil for the gears...lotta people put 80W90 gear lube in them mistakenly...running something too thick can blow a gearset apart if run hard too soon in cold weather, etc...I towed a Nissan Sentra that's box grenaded for that very reason a few years back, guy was going 80 mph down the highway not 2 minutes from his house in 15 degree weather, bosses in the case overstressed and came apart, destroying the case casting...something you don't see much outside of racing.

A lube that can't move out of the way fast enough, stuck between precisely matched gears can put an amazing amount of hydrostatic force on shafts and bearings, something's gotta give...and it did..

The older Chrysler MTX's used Dexron ATF in the box...found a lot of them with the wrong stuff in 'em too...

[elvin331]

Originally Posted by G.A.S.

Yea, what jeff said.
there is no reason to use anything other than what the manufacturer recomends .
Oil is not oil my friend, I deal with bio hydro fluids, synthetic oils and fluids and everything down to the universal traction fluid on a daily basis in the equipment I maintain. You could cause damage to anything right down to a 20.00 seal.
Why are you asking?

I was at another forum and someone asked what should he use for his manual tranny. people were giving differnt recommnedations and someone suggested 10w30 motor oil, I said that although Honda recommends it as A Temp replacement, it should not be used continously because it can cause stiff shifting. Someone called me stupid and an idiot for saying such a thing.
I personally believe that all oil is not the same and am sticking to what Honda recommends, which is Honda MTF for manual and HOnda ATF for auto.