Lube foaming in Transmission

[Menaces Nemesis]

Need some help from the Deuce Gurus please...

The lube in my M275's 5-Speed Spicer is foaming. Not just a little, I'm talking some serious froth here. Subsequently, shifting seems to get tougher while driving as the lube gets churned, and then gets easier again when it sits (overnight) and has had some time to settle the bubbles out. Previous owner says it's straight 40w motor oil. The lube level is within spec, about 1/2" below fill-plug level. I don't believe the lube is water-contaminated because it's amber/clear and not milky.

Seems obvious the lube has to be replaced, and I've read that 30w, 40w, or 50w non-detergent motor oil is better than GL-5, but my questions are; have any of you had the same problem? did you figure out what caused the fresh-looking lube to foam? and what brand/grade/weight/type of lube cured it?

Thanks in advance for your replies,

MN

 

[rustystud]

This is what I recommend you use.


View attachment Scan0171.pdfView attachment Scan0172.pdf

Yes you can get "away" with using a straight weight engine oil but that is not the best oil you can use in a manual transmission. Almost all the transmission manufactures recommend you use a "Synthetic 50 weight gear oil" .

 

[dmetalmiki]

Totally agree with the above, why get by with '(it) 'will do'..Personally all our trucks are oep 220. (and or oep 110).

 

[snowtrac nome]

a manual trans will want hypoid gear oil like that spirax or your standard 80/90 the gears need the extra sulfur content in the hypoid gear oils. the exception to that rule would be the new transmissions like the nv 4500

 

[Menaces Nemesis]

This is what I recommend you use.


View attachment 666204View attachment 666205

Yes you can get "away" with using a straight weight engine oil but that is not the best oil you can use in a manual transmission. Almost all the transmission manufactures recommend you use a "Synthetic 50 weight gear oil" .

Would the 50w synthetic trans lube be a good choice for the Rockwell t-case also? I went ahead and ordered some 50w synthetic trans lube. Trans is, and will be, draining overnight, and will be filled with the new stuff when the "Brown Truck of Happiness" drops it off tomorrow. Would've gone with the Spirax, but the cheapest, smallest quantity I found was a 5 gal bucket @ about $270 with shipping. So, bought 2 gals of the Lucas instead (with free shipping from Summit Racing).

Thanks again,

MN

 

[rustystud]

Would the 50w synthetic trans lube be a good choice for the Rockwell t-case also? I went ahead and ordered some 50w synthetic trans lube. Trans is, and will be, draining overnight, and will be filled with the new stuff when the "Brown Truck of Happiness" drops it off tomorrow. Would've gone with the Spirax, but the cheapest, smallest quantity I found was a 5 gal bucket @ about $270 with shipping. So, bought 2 gals of the Lucas instead (with free shipping from Summit Racing).

Thanks again,

MN

Since the transfer-case is meant to "shift on the fly" the Spirex 50W would be an excellent choice.