Gear Oil

[Jim-ME]

I recall reading about not using GL5 compatible gear oil in Series rigs. I've done a search and can't find anything. Is there a problem using GL5? I have looked high and low and can't find GL4.
Thanks,
Jim

[Lalo88DK]

I recall reading about not using GL5 compatible gear oil in Series rigs. I've done a search and can't find anything. Is there a problem using GL5? I have looked high and low and can't find GL4.
Thanks,
Jim

It's true GL5 oil have different additives that are bit harsh on the brass synchromesh rings in a Series gearbox, but it's quite difficult to find GL4 oil nowadays, unless you buy a hole barrel, but GL4 is the one to use for Series gearboxes.

[kevkon]

Use Amsoil Synthetic Manual Synchromesh Transmission Fluid (MTF).
Our hosts sell it.
And while your at it get the hand pump, it makes the job a whole lot easier.

[jac04]

^^ Why in the world would you ever use the Amsoil MTF in an application calling for 90 weight (or 80W-90)?? According to the Amsoil web site, MTF is 5W-30.

http://www.amsoil.com/storefront/mtf.aspx

Oh, and the yellow metal issue with EP additives is only at elevated temperatures (like 240 F and above), so don't wory about it. IMO, most syncro problems are due to the limited slip additives that are common in most gear oils.

[TeriAnn]

Most tractor & farm equipment stores carry GL-4. Stai-Lube sells GL-4 in the gallon container & most auto parts stores can special order from Stailube. Bad news is minimum order is usually a 4 gallon case. But you will use it all over time with oil changes. I have a semi local auto parts store that caaters to do it yourselfers who stocks Stailube GL4 by the gallon as well as Castrol LMA brake fluid by the quart.

If worse comes to worse British Pacific carries GL4 Stailube. They don't buy enough to get a discount so you pay full list through them.

http://www.britishpacific.com/BPSite/LandRoverAccessories/Land_Rover_fluids.html#GL4_oil

[luckyjoe]

Pennzoil still makes a Gearplus GL4, but none of the local shops distribution centers carry it. Last time I found it I purchased 4 5-gallon pails...

Tom P.

[kevkon]

^^

Oh, and the yellow metal issue with EP additives is only at elevated temperatures (like 240 F and above), so don't wory about it. IMO, most syncro problems are due to the limited slip additives that are common in most gear oils.

Thanks for that info. So there's really no point in hunting down the lower sulfur GL-4 gear oil, that should save everyone some aggravation.

[yorker]

^^ Why in the world would you ever use the Amsoil MTF in an application calling for 90 weight (or 80W-90)?? According to the Amsoil web site, MTF is 5W-30.

http://www.amsoil.com/storefront/mtf.aspx

Oh, and the yellow metal issue with EP additives is only at elevated temperatures (like 240 F and above), so don't wory about it. IMO, most syncro problems are due to the limited slip additives that are common in most gear oils.

The viscocity ratings for different types of oil differ and overlap. 75 wt gear oil is approx the same viscocity as 10 wt engine oil. Many modern gearboxes use a 75W90 gear oil, which is ~ equivalent viscosity to a 10W40 motor oil.

The higher sulphur (when exposed to moisture and heat) in GL5 can cause issues in earlier transmissions, it is sometimes supposedly "buffered" so it won't be an issue however even this has been a subject of great debate over the years.

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1676896&page=1

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1078234

[jac04]

Just look for something with a MT-1 and GL-5 rating. The MT-1 will indicate non-active sulfur. Its my understanding that most gear oil manufacturers have switched to non-active sulfur.

[yorker]

I don't know why you wouldn't use Sta-Lube's GL4- it is available at most shops I have been to and if not in stock they'll often order it. NAPA here has it, as does Pep Boys.


In any event it is a perpetual debate...

[yorker]

FWIW

[jp-]

The viscocity ratings for different types of oil differ and overlap. 75 wt gear oil is approx the same viscocity as 10 wt engine oil. Many modern gearboxes use a 75W90 gear oil, which is ~ equivalent viscosity to a 10W40 motor oil.

T

I'm not sure about this. I know for a fact that 75W oil is thicker than 10W motor oil. It pours a hell of a lot slower!