What Type Of Oil:

[Rob]

Getting ready to drain my duplex in the B67. What type of oil should go back into this, and about how much? I think the oil that is in it is synthetic because it is red/dark, and smells strange. It does not have the gear lube smell at all. I spoke with my Mobil rep and he says they have SAE 50 transmission oil that is mineral based. I think that is the correct product, but would like confirmation.

Also going to change the drive axles lube. I suppose 85-90W would be alright here but should I go with the heavier stuff to just putz around in?

Thanks,

Rob

[B61TENDT711]

I been running 80w-140 AMSOIL in my Triplex, and SAE190W AMSOIL in my Diff's, they get changed every spring drained n refilled. . .

Farm & Fleet has a brand called Mystic that is Red in color and has an odd smell to it but i assure you it'sa good lube i have used it in the past, but i figured i been using AMSOIL engine oil i may as well run there other products as well being a dealer of the stuff and all. . .

EDIT:

I have found synthetic offer's better protection in Vehicles that sit a lot as they don't break down into an acidic liquid like the Dino lubes do . . .

Plus better lubrication and wear protection when ran every day . .

Mike

[Rob]

I been running 80w-140 AMSOIL in my Triplex, and SAE190W AMSOIL in my Diff's, they get changed every spring drained n refilled. . .

Farm & Fleet has a brand called Mystic that is Red in color and has an odd smell to it but i assure you it'sa good lube i have used it in the past, but i figured i been using AMSOIL engine oil i may as well run there other products as well being a dealer of the stuff and all. . .

EDIT:

I have found synthetic offer's better protection in Vehicles that sit a lot as they don't break down into an acidic liquid like the Dino lubes do . . .

Plus better lubrication and wear protection when ran every day . .

Mike

The Mystic would not surprise me as the gent that formerly owned the truck was an avid "Farm & Fleet" shopper. I checked all the fluids and they are right to the top when cold. As long as the truck has been sitting they need changed anyways.

Thanks,

Rob

[Packer]

I use 80-85w gear lube or 50w motor oil.

The motor oil I use for the first change.

Seems the motor oil will clean up the trans on the inside.

Loosens the crud and gunk that may be in there and then change it out.

Ran 50w motor oil in KW's, Pete's and such as that was the recomended oil for Dana and Spicer transmissions.

The issue with mineral oil added to gear oil, or gear to mineral oil is a 'Tar' type stuff that builds up.

Transmission life is VERY short!!!

The tar sticks to the case and not the gears and bearings.

When you open the case up, all you'll find is all the pats in the bottom in itty-bitty pieces!!!

Have heard but never done the following:

Drain both cases

Fill with diesel

Put main in gear and aux. in netural

Run engine at idol for up to 1/2 hour

Drain

Refill with 80-85w or 50w engine oil

Run 2-5000 miles

Change again and run for standard change life.

This is for mineral to gear oil, or gear oil to mineral oil.

'OR' unknown to what you want back in.

Packer

[HK Trucking]

50W is for Eaton Fuller transmissions.

85w 90 is for Mack transmissions.

.

[Rob]

50W is for Eaton Fuller transmissions.

85w 90 is for Mack transmissions.

.

Hi Herb, it is the EP additive that concerns me. I have both GL-4, and GL-5 in the shop, but both contain this additive. Others have told me no go in transmissions due to eating on bronze, and too stiff to flow properly into needle bearings.

I've bought synthetic for my Eaton transmissions although not used it yet.

Thanks,

Rob

[B61TENDT711]

I have had great luck with AMSOIL synthetic . . .

I'm running the 60wt in the engine 80w-140 in the transmission and 190wt in the diff's and my old has been running happy for 10+ years now . . .

Mike

[HK Trucking]

Hi Herb, it is the EP additive that concerns me. I have both GL-4, and GL-5 in the shop, but both contain this additive. Others have told me no go in transmissions due to eating on bronze, and too stiff to flow properly into needle bearings.

I've bought synthetic for my Eaton transmissions although not used it yet.

Thanks,

Rob

Hi Rob.

If the extreme pressure additives are that harmful to bronze, then what about the bronze thrust washers in the rears?

I think someone was BS'ing you on that.

The Mack service literature from back in the day called for 90 weight gear lube in the Mack transmissions, and all of them that I ever serviced got that type of oil, or later on, 85w90.

Herb.

[theakerstwo]

Rob for many years the mack trans used same as the rear end as long as you used a GL5 grease. I would not use the other like a 85/140 in it. It needs the GL5 because the gears are a helix cut meaning they are sliding on each other. This means they need a extrem pressure lub.I would not use a 50w motor oil. That is ok for a straight cut gear.I know mack did not use the mineral oil in their trans. But fuller did at one time but there was too many guys that would mix rear end gears with the mineral oil and like done said i have opened up trans that had the lub mix and there was a bed of tar looking stuff with a place that the gears had spung out and the grease would have to be cut out.