GL-4 vs GL-5 axle fluid.....

[Fordiesel69]

For a troy bilt roto tiller it states GL-5 can only be used for slight top offs. GL-5 is not to be used for fluid change out. Rather GL-4 should be used.

Problem is I cannot find GL-4 anywhere.

What is the difference, I would think GL-5 is better.

 

[sciphi]

It depends what metals make up the gearbox. If there are any bronze gears (IIRC) in there, the old-style GL-5 lubricants used to degrade those very quickly.

Royal Purple "synchromesh" fluids are GL-4, and should be available over the counter. Or a 75w-90 GL-4 gear oil should work too. I've seen them at NAPA.

 

[Fordiesel69]

It has bronze gears and bushings does the new fomula gl-5 fluids eat it up. I bought autozone coastal fluid made by warren oil company.

 

[NHGUY]

Sometimes its confusing,because some brands (Amalie for example) states both GL4 and GL5 coverage on the same label.

 

[oliver88]

Redline MT90 or Amsoil SVG both are GL-4 only lubes

 

[JZiggy]

Ummmm... Amsoil SVG is a GL-5 spec'd fluid.

If you really need GL-4, it's probably easiest to pick up some Sta-Lube from NAPA.

 

[mechtech2]

GL5 could be harmful to brass/bronze, with moisture and heat.
But so was GL4 - it had about 1/3-1/2 the corrosive sulfur - it was not void of it.
Modern GL4-5 lubes are almost always 'buffered' , and are safe.

 

[Ken2]

Quote:
some brands ... states both GL4 and GL5 coverage on the same label.
This indicates that the additive package to reach the GL-5 spec is the newer stuff that won't harm the metals in the gearbox where GL-4 was spec'ed. I'd use any gear oil with this on the label.

 

[mechtech2]

Gl4 and GL5 in the same product also means it is suitable for Hypoid gear aplications, which Gl4 normally is not.

 

[MolaKule]

What's the specified viscosity?

If it uses a 75W90 I would use Amsoil MTG or eqiuivalent.

 

[widman]

Quote:
This indicates that the additive package to reach the GL-5 spec is the newer stuff that won't harm the metals in the gearbox where GL-4 was spec'ed. I'd use any gear oil with this on the label.


NO.

Short version:
GL-5 should not be used where GL-4 is specified unless there are no soft metals involved.

Long version:
Difference between GL-4 and GL-5


There are a lot of proper GL-4 oils out there, including the NAPA product that should be easy to find, and is reported to be cheap.

 

[SXE10]

Originally Posted By: Fordiesel69
Problem is I cannot find GL-4 anywhere.

Redline MT-90 & Amsoil MTG are two 75w-90 GL4 that spring to mind as have been mentioned by others.

Lots of people (including myself) have used MT-90 with great success in the Aisin-Warner AZ6 (6spd manual RWD) as found in the Toyota Altezza/Lexus IS200, Mazda MX-5/RX8, Honda S2000 & Nissan Silvia where a GL4 is called for. Mind you they're not gardening equipment

 

[Fordiesel69]

Anyone have the part# on the napa stuff. My local store is not very good.

 

[azsynthetic]

Try a motorcycle shop. They usually carry GL4 75W90 for two stroke bikes.

 

[Jim Allen]

Also, are there not some GL-5 oils also rated dual/rated for GL-4?