Hypoid Trans Fluid or Non Hypoid?

[Klotz1]

Hello all! I am going to be changing my Transmission oil in my Harley Big Twin 5 speed, I noticed some oils say Synthetic Hypoid and others say just Synthetic Non Hypoid??. Which one you think is better for my application, I am currently using Spectro synthetic non hypoid 75W140 GL1.

 

[BBDartCA]

do not use hypoid gl5 type lube, sludge can form if run real hot. The add pack for hypoid & bevel gear sets is not needed in a main trans either, and can lead to these sludge problems.

 

[BigCahuna]

I run a mineral based 75/90 gl-5 rated gear oil in my trans.Some guys run the synthetic version of the same weight. I've never heard of trans oil sludging up in a Harley trans, unless it had water in the oil.Some metric bikes call for a 80/90 wt Hypoid oil for their rear end gears which also has a gl-5 rating.,,

 

[Klotz1]

Thanks for your input, I did some research and it seems that the hypoid gear lubes are used more for shaft driven and older chain type bikes. I also found out it can be corrosive to yellow metals such as copper or brass in bushings or synchronizers.

 

[heavyhitter]

I use M1 75w90 or 75w140 on mine never have a problem. Change every 5k.

Dont use it in your primary though, it can cause issues.

 

[Klotz1]

As long as the M1 gear does not contain Hypoid your OK, I also use a 74W140 (non hypoid Synthetic). It is extremely important to note that EP (Extreme Pressure) additives are corrosive to yellow metals such as copper or brass in bushings or synchronizers. GL1 is the class of gear oils that does not* contain EP additives, so it is the correct gear oil for you. It may or may not hurt Harley MC transmissions, I personally wouldn't use it.

 

[heavyhitter]

Originally Posted By: Klotz1
As long as the M1 gear does not contain Hypoid your OK, I also use a 74W140 (non hypoid Synthetic). It is extremely important to note that EP (Extreme Pressure) additives are corrosive to yellow metals such as copper or brass in bushings or synchronizers. GL1 is the class of gear oils that does not* contain EP additives, so it is the correct gear oil for you. It may or may not hurt Harley MC transmissions, I personally wouldn't use it.



This makes no sense. NO gear oil contains Hypoid. The term has more to do about the design of the gear case NOT the oil. A hypoid is a type of spiral bevel gear whose axis does not intersect with the axis of the meshing gear.

GL4 is kinder to yellow metals than GL5.

Hypoid gear oil has additives to resist heat better than regualar gear oil but there is no such thing as hypoid in oil.

 

[Klotz1]

Yes, your correct, my apologies. I wrote incorrectly, I should have wrote gear lube Labeled for Hypoid vs lube for non hypoid gears.