GL 1-5 Gear Oil

madmike · Post by **madmike** » Fri Jun 24, 2011 10:20 am

I know this subject has been discussed several times but due to lack of GL1-4 I am asking for input in a little different manner. Bt the way, I checked with NAPA and the 65-201 cannot be ordered. The lucky guy that got one apparently got old stock.

I am under the belief that the differentials we use do not have brass in them. If that is the case, then I would next believe that it would not matter what Gl number we use. That brings me to synthetic. After reading all the labels in several auto parts stores, the synthetic or maybe a product like Amsoil comes to mind and I would like feedback from our readers. I know Wes mentioned there is no guarantee given by the oil companies when they say safe for brass, but at some point we may have to place some faith in one product over another due to the unavailability of the correct stuff.

Lastly, what is the problem with hypoid oil? I read somewhere that we should avoid hypoid but one of the products I saw was hypoid and recommended for brass parts.

Submitted by....Dumbfounded again....

Bretto · Post by **Bretto** » Fri Jun 24, 2011 10:32 am

I beleive the hypoid doesnt help out the synchros by allowing too much slippage.
I'm not to sure I'd trust that counter guy. You can order it on their site. Have you tried to order it online to ship to the store? My local Napa store by me had it in stock.

Post by **wesk** » Fri Jun 24, 2011 10:58 am

What you use is your choice. It's your wallet.

Modern differentials require hypoid oils because of the heavy gear loading caused by their design. All the other gear boxes have no need for the hypoid quality in their gear oil. Reasoning that should be applied here is "if I do not need it why buy it". Hypoid gear oil is more expensive normaly than straight gear oils. The hypoid oil manufacturers push it's use in all gear boxes for the profit not the need to use it. When the sulpher content got too high in the later hypoids it was determined by many users that it contributed to shorter life of non-ferrous metal. The hypoid manufacturers did not want to lose a market segment so many claim it won't harm non-ferrous metals. They don't prove it they just say it.

So it's your choice. Pick whatever gear oil you like. I'll stay with a quality regular gear oil meant for regular gear boxes and save the hypoid oil for the proper application , modern offset ring and pinion differentials.

If you are having a hard time finding regular gear oil it's because the market has been brain washed into using the more expensive gear oil in all gear boxes. So now you must specify Regular gear box oil. Go to the Shell, and Royal Purple web sites and review their offerings in NON-HYPOID gear oils.

If you want a quick shot at finding a quality regular gear oil locally go to your truck fleet operators, tranny rebuilders and farm equipment sales and service.

TomM · Post by **TomM** » Fri Jun 24, 2011 12:08 pm

Gear oil for older manual transmissions is available, even in California. Or for a price you can mailorder. Simply add to cart.
Synthetic is overkill for how we use our jeeps (unless you live in northern Canada and Alaska).

MT-90 75W90 GL-4 Gear Oil

via mail order here:
http://www.redlineoil.com/product.aspx?pid=46&pcid=7

75W90 GL-4 gear oil (similar to SAE 5W40/10W40 engine oil viscosity)
Popular in Nissan, Mazda, Mitsubishi, VW/Audi, Lotus Elise/Exige, Toyota
Offers quicker shifts, perfect synchronizer coefficient of friction
Safe for brass synchros, as it lacks the reactive sulfurs found in most GL-5 oils that cause damage
High performance gear protection and longer synchro life
Eliminates notchy shifting, even when cold
Satisifies the gear oil viscosity requirements of 75W, 80W and motor oil viscosities of SAE 40, 10W40, and 15W40
Recommended for GL-1, GL-3, and GL-4 applications, as well as where most special synchromesh fluids are specified

AeroE · Post by **AeroE** » Fri Jun 24, 2011 6:40 pm

As I posted on a different topic; I had no problem getting several gallons of GL-1 from NAPA this month. They said there were at least a dozen gallons in their local warehouse. Maybe it's a regional issue, here in the MW a lot of farmers use straight gear oil.

DJ · Post by DJ » Fri Jun 24, 2011 9:40 pm

My NAPA had gallons and a five gallon in stock.

madmike · Post by **madmike** » Sat Jun 25, 2011 1:30 pm

Thanks to all for your input and contacts. At least I know I can get it one way or another. As far as price, adding shipping to get this oil mail order would most certainly make GL1-4 more expensive but the important thing at this point is to get the right stuff. I will pay that price gladly. I am going to call a NAPA dealer in another city and see what they say. I did contact one ranch supply and one local bulk dealer (Pacific Pride). Both had GL-5 and synthetic but not he right stuff.

The local NAPA dealer has recently been managed by the owner's son and the quality of counter person has nose dived. I have socks older than most of them and they have not a clue what a military Jeep is or it's counterpart, the CJ series. If it isn't in the computer they have no brain cells to figure out how to provide customer service. It's entirely possible that I will be able to get the NAPA product and I will update my post if so. Once again thank you for helping. I live somewhat remote to a large metropolis and have limited resources except the computer and then I have limited ability

But I'm workin' on it.

madmike · Post by **madmike** » Sat Jun 25, 2011 2:14 pm

My local NAPA store did it to me again. After doing an internet search on the link Tom provided I found a dealer for Redline oil in Oakhurst, about 35 miles from me. He is also a NAPA dealer. I asked about NAPA Product No. 65-201. He said I just got 4 gallons yesterday. I will never believe ANYTHING people in the Mariposa store tell me EVER. So Thank you Brett, Tom, Wes and all for taking the time to get me straight on this matter.

Mike