75/90 Synthetyic gear oil

Trevor · November 02, 2015, 06:18 PM

I'm trying to track down some 75/90w Synthetic GL-4 gear oil options for Roy and Michelle's D130 transfer case and diffs. But having a hard time finding vendors that sell what I'm after...

Redline...JB's Automotive, but they've got none in stock
Pennzoil...everyone sells the motor oil, but does anyone know who sells their gear oil? Crappy Tire doesn't.
UFA only sells by the GL-4 stuff by the bucket, so they're not an option.

Anyone have any recommendations of where to go? I always buy pails from UFA, so I'm not familiar with who carries what GL-4 in the 5L jugs

Red90 · November 02, 2015, 07:36 PM

Why GL-4?

binch · November 02, 2015, 07:57 PM

Greg distributors:

http://www.greggdistributors.ca/Catalogue.aspx

(but not sure what's gl5 or gl4)

Castrol syntec by the lt.
Lucas synthetic by the lt.
Nemco synthetic gear lube by 4 lt

Mopac and Jegs on the west end could very well have some of the MTF oils for the gearbox that John lists in his table.

Napa should carry Amsoil but best call to find out if they have the MTF

A few options there......

Trevor · November 02, 2015, 07:59 PM

Quote from: Red90 on November 02, 2015, 07:36 PM
Why GL-4?

Want to stay away from GL-5 in the transfer case as its hard on bronze.

Trevor · November 02, 2015, 08:01 PM

Quote from: binch on November 02, 2015, 07:57 PM
Greg distributors:

http://www.greggdistributors.ca/Catalogue.aspx

(but not sure what's gl5 or gl4)

Castrol syntec by the lt.
Lucas synthetic by the lt.
Nemco synthetic gear lube by 4 lt

Mopac and Jegs on the west end could very well have some of the MTF oils for the gearbox that John lists in his table.

Napa should carry Amsoil but best call to find out if they have the MTF

A few options there......

Hand't thought of Gregg's. That's handy too.

They're ok for gearbox oil, its recently changed and a synthetic already. So they are all good for MTF. It's just the t-case and diffs that are currently running mineral oil and need to be changed out. They did stop by Napa earlier but couldn't find anything other than the standrd GL-5's...and AMSoil or Royal Purple. But as they are on a budget, they would prefer to not pay those higher prices for Amsoil/Royal Purple. Its pretty pricey stuff.

Red90 · November 02, 2015, 08:02 PM

What bronze is in the transfer case?

Red90 · November 02, 2015, 08:03 PM

In reality no gl-5 synthetics will have white metal corrosion issues. Really it is only a concern with cheap gear oil.

Trevor · November 02, 2015, 08:11 PM

Quote from: Red90 on November 02, 2015, 08:03 PM
In reality no gl-5 synthetics will have white metal corrosion issues. Really it is only a concern with cheap gear oil.

Seems to be a long running debate, with the Gl-5 being hard on the white metals. I have no idea whether its valid or not, but I've yet to read anything about GL-4 being hard on bronze/syncro's, etc, so I just stay with the GL-4 throughout.

Insofar as bronze in the t-case goes, is there not bronze bushings in there? Never had one apart myself, so I am not sure. There was a thread in the old forum I believe on this subject, and the warning was to not use GL-5 in the T-case due to its effects on the bronze bushings (and also to stay away re the gearbox syncros).

Red90 · November 02, 2015, 08:16 PM

There is a huge amount of misinformation running around about GL-5 and GL-4. Neither specification has anything to do with white metal corrosion in any way. The problem arose in that an additive used to be added to gear oils to make them meet the GL-5 wear tests. This additive was corrosive to white metals. That "bad" additive was replaced decades ago with a safe one and unless you purchase Billy Bob oil from Thailand, there is nothing to be worried about and a GL-5 will give better gear protection.

Regardless. LT230s don't have bronze parts, do they?

What IS important is that when you choose a fluid for a synchronized gearbox, you get one that had friction modifier that INCREASE the friction so that the synchros can function properly. So unless there are synchros, you should use a GL-5....

http://www.widman.biz/uploads/Transaxle_oil.pdf

Red90 · November 02, 2015, 08:20 PM

Quote from: Trevor on November 02, 2015, 08:11 PM
Insofar as bronze in the t-case goes, is there not bronze bushings in there? Never had one apart myself, so I am not sure. There was a thread in the old forum I believe on this subject, and the warning was to not use GL-5 in the T-case due to its effects on the bronze bushings (and also to stay away re the gearbox syncros).

Nope. All shafts use roller bearings. No synchros, no concern. The concern is not corrosion of white metals. The concern is solid lubricant coating of synchro faces that results in low friction.

Like I state above. The internet has become a horrible breeding ground for incorrect information.... My second pet peeve is the wrong theories on engine braking.

Trevor · November 02, 2015, 08:36 PM

Well, that makes things a ton easier then. That's good info John, thanks!

Already a Rover · November 03, 2015, 10:28 PM

Just bought some yesterday at Bowness Auto. Pricey stuff!!

I believe the extra additive is a phosphorus compound. Indeed it 'can' be in or out of GL4 or GL5, but GL5 has twice the concentration(s). Yup, been doing some reading. It starts to make sense after awhile.

jim

ugly_90 · November 12, 2015, 09:59 PM

I don't really understand the appeal of a synthetic gear oil for a vintage landrover axle. Unlike an engine oil, an axle oil isn't running in as much heat and pressure, and it wouldn't break down as readily.

Also, the gear oil in axles is often exposed to moisture, whether in regular driving, or water fording. If the synthetic oil was milky or with dirt, it would need to be exchanged anyhow. So no net benefit for synthetic again.

I don't know how aged axle and diff seals would react to synthetic either, perhaps not well.

I'm ok with synthetic where required for engine and transmission, but I don't see the benefit for axles and spindles.

Trevor · November 13, 2015, 08:14 AM

Roy and Michelle were heading to the 70th latitude in northern Russia during the middle of winter, hence why they were wanting synthetic throughout. They had mineral oil in there, which would have been a tad stiff at -50c.

Red90 · November 13, 2015, 08:21 AM

This thread was mostly not about vintage Land Rovers or their axles. It was discussing the use in the transfer case of a Defender. The biggest benefit is better low temperature viscosity. Synthetics are a 75W90 with many close to a 70W90. Non synthetics are 80W90 or 85W90.

Below are the temperatures at which each grade needs to pass the ASTM D2983 test for a viscosity of 150000 cP. More or less this is about as thick as you can get and still have the oil move around.
70W, -55
75W, -40
80W, -26
85W, -12

If you are running the truck in the winter and parking outside, it can be worth it to protect against metal contact during the first start of the day. The same does go for axles as well.

If you get water in your axles or gearboxes, you should be fixing the seals and breather ASAP.

Normal wear protection will not be any different other than the severe cold stated above, except possibly if you have more complex diffs like an ATB. That said, the transfer cases can run hot if you do higher speeds in hot weather. Not sure if it is hot enough to damage the oil.