Tranny/transfer case oil

[Carls_jeep]

Everyone knows this is a long going discussion on almost every site dealing with older trannys that have brass in them. When I rebuilt my tranny and transfer cases about two years ago I researched and found that Marathon GL4/5 was supposed to be compatible with brass. I emailed Marathon and asked and was told it was safe so I used it.

Now I started wondering about others claim of issues with GL4/5 oil so I just drained some from my tranny and looked at it. Well, there is a slight glitter of brass in the oil so Marathon has lied to me and obviously everyone else. Now I tend to believe that anything but GL1 or straight 30w or 40 weight oil is the only thing to use in trannys with brass in them.

The only other possibility is normal wear for about 2000+ miles of use. I don't want to take a chance any more.

I just bought 5 gal of straight 30w oil and the tranny and transfer cases are draining at this moment and will be filled with the 30w oil. I have been using 30w oil in the transmission/rear axle of my tractor as recommended by the manufacturer since it was new and it has close to 1000 hours now with no tranny rear axle problems.

I also have searched about engine oil vs GL1 mineral oil and so far as I can find they are the same with, only the additives may differ.  

[1955CJ-5]

I found some GL-4 at Napa Auto. It is supposed to be OK. Someone on one of the forums just uses 50w engine oil.  The old MG that I have uses 30w motor oil and that works just fine.

Maybe your brass glitter was just from breaking it in...either way the motor oil should solve the problem.

[bretto]

I tend to think a 30w would be a bit too thin in the summer months and a 50w would be better.  In cold months I bet it would be great.  This GL-1 in my box is so thick, my weak starter has to have the clutch releases to even start her up.

[athawk11]

Every time I read the gear oil threads, my stomach aches. �I researched a lot of sites and opinions then decided to go with the Valvoline 80w 90 GL5 �With the [size=14]MT-1[/size] rating. �
If you reasearch it, the MT-1 classification is designed for HEAVY equipment, non synchronized gears, gold metals safe. �

All the oil companies say, "You're good to go!!

Some of the forum participants from many sites say, "You're good to go!!"

Some of the forum participants from many sites say, "Don't use it. It's not safe."

It's enough to make my head hurt... :-/ I liked the protections added to the modern gear oils, but still felt anxiety while filling the cases. �

I've had the above oil in my tranny and TC for 1 year. �I have had no issues. �I am going to drain it all and inspect it this weekend. �If it shows no sign of brass, I will continue to use it. �

If I see the slightest sign of shiny brass, I will replace it with GL-1 mineral oil, and will join Carl in calling the oil companies liers.

For me, this will put it to rest for good. �I'll let everyone know what I find.

Tim

[Carls_jeep]

It's true there was very little brass showing in the oil but it was enough to scare me and I don't want to rebuild it again. I took it out for a 10 mile test run and did many start stops and I believe it shifts a little easier now. Time will tell. I have also heard that a thinner oil aids shifting. I don't expect any summer issues of the oil being to thin.

Here's what you have to look for in the oil if the manufacturer will tell the truth. If it has any EP additive it has sulfur and is corrosive to brass. If the oil has any sulfur additive at all the brass will be affected.

85-90w GL1 oil has no EP additives and is equivalent to 30w non detergent engine oil. They are both mineral oils. the engine oil may have some additives but none are harmful to brass.

I have used my tractor in the 90+ deg F heat of summer WAY harder than I would ever use my Jeep. There is no way I could load the Jeep down as hard as I have the tractor for hours in a day and the tractor with 30w engine oil in the transmission/axle housing has never given any indication of trouble.

I suggest anyone that has anything other than GL1 or 30w engine oil in their tranny/transfer cases change it.

[Comanche_County]

What about synthetics?

[athawk11]

CC,
I should mention, the Valvoline GL-5, MT-1  I am running is synthetic.  Still stinks like regular gear oil.

Tim

[calvinhunt]

This is a thread I will be watching closely. �I'm anxious to see what each has to say. �For now, I can't help but think that the first run after overhaul, with any oil, there will be showing of brass from moving parts setting up a wear pattern. �I believe the best indicator would be what the second run looks like. �In the aviation industry after the overhaul of an engine or gear box we removed the oil filter after 10 hours of operation.  We open the filter assembly and remove the filtering material to inspect for metal particles.  A small amount is typical.  We look for the amount of metal particles to decrease to nothing within the next few inspections after which we go to 50 hour intervals normally.

[Carls_jeep]

Something to think about. The odor of gear oil is because of sulfur. If an oil smells like gear oil there is a strong potability it has sulfur in it. The probability of an oil company putting something other than sulfur in their oil to make it smell like sulfur is so remote it shouldn't be even considered. At least I won't.

So, in conclusion if it smells like sulfur it's probably contains sulfur.

Calvin, in a few months I plan to check for brass in the oil again and i hope this time I can get the plug in before most the oil falls on the floor. It was hard to clean up the mess. �;D �:

[athawk11]

Let me set up the conditions. �PO had rebuilt the TC and Tranny just prior to my purchase in 2010. �I drove the Willys that summer. �By fall, I drained the cases in preparation for cleaning, paint, and new seals. �When I drained the cases, they had the stinky smell of gear oil. �What type of oil, I will never know. �I went back this far in history so to eliminate the 'break in' argument. �These cases are broke in. �

In late 2011 I refilled the cases using Valvoline 80w-90 synthetic GL-5 with an MT-1 rating. �MT-1 is suppose to be safe for gold metals. �I ran with this gear oil for a full year with no obvious mechanical problems.

I drained the gear oil this morning from both cases. �I inspected the oil under bright light.

So, in conclusion...

If you have GL-5 or GL-5 with an MT-1 rating, immediately drain them from your Willys. �These gear oils are not safe to use. �These gear oils are eating your synchros. �

I've already picked up my jug of GL-1 Mineral Oil/Gear Oil from NAPA. �I gave it the smell test. �No stinky sulfur smell. �

I wish I had better news. � I am not an expert...and my findings will likely do very little to sway what you might believe, but for me, this argument is OVER.

Tim

[Carls_jeep]

I am completely convinced that any gear oil except the GL1 has sulfur in it. Especially if there is and sulfur smell at all and if a brand of GL1 has the sulfur smell don't use it. Also, since I put the Marathon 30w engine oil in my tranny it is shifting lots better and I know that oil will not harm the brass. I got it warmed up real good today on a long run and it shifts much smoother now.

[calvinhunt]

In late 2011 I refilled the cases using Valvoline 80w-90 synthetic GL-5 with an MT-1 rating. �MT-1 is suppose to be safe for gold metals. �I ran with this gear oil for a full year with no obvious mechanical problems.

I drained the gear oil this morning from both cases. �I inspected the oil under bright light.

So, in conclusion...

If you have GL-5 or GL-5 with an MT-1 rating, immediately drain them from your Willys. �These gear oils are not safe to use. �These gear oils are eating your synchros. �

I've already picked up my jug of GL-1 Mineral Oil/Gear Oil from NAPA. �I gave it the smell test. �No stinky sulfur smell.

Tim,
Just three days earlier in your post above it seemed you were telling us that you were pleased with the GL-5 with the MT-1 rating.  Why did you drain that oil?  Did you start to question it?  Even though you didn't say it, it's apparant that you found shiny metalic particles in your gear oil when drained.  I'm asking these questions because I'm concerned.  I thought I had read early gear oil posts on the old site and saw from trusted individuals that it was GL-4 I wanted in my tranny and TC.  I read on the GL-4 container and it said it was for gear boxes containing brass components.  I put a lot of trust in your opinion.  

Carl,
I also put a lot of trust in your opinion, as well.  How do you dare run 30 w oil in a gear box where the manufacturer says it was designed for 90 w?  I kind of like the idea of engine oil but why not a heavier weight?  I have really learned to respect aircraft engine oil.  It is manufactured under strict MIL SPECs.  They make it in miltiviscosity and in straight weights.  They make it in compounded and noncompounded (detergent or nondetergent).  It's available in 30w, 40w, and 50w.  The 50w appeals to me.  

I would appreciate any further info from you two gents or from anyone else who has an equally strong conviction about a different product/answer.

[athawk11]

Calvin,
I appreciate your comments and thoughts.

From previous research, I felt the GL-5//MT-1 rating would be safe for use in our little Willys Jeeps. �For a year, the shifting was smooth and trouble free. �I believed the oil companies that said we are safe with this MT-1 rating.

I also liked that I could tell which oil was leaking by giving it the smell test.

More than anything, I drained the gear oil to cure my curiosity. Plus, I respect Carls knowledge, and he made me nervous. �I just needed to have a definitive answer to this never ending conversation. �At least for myself.

I did find shiny brass particles in the oil. �These boxes had been 'broken in' long before I refilled them with this bad gear oil, so the particles were new and likely a result of the gear oil I chose.

I'm not sure about the GL-4. �I will have to yield to Carl on that. �I'm about to contradict myself a bit. �I trust Carl, but the 30w oil he has chosen seems 'light' to me. �So, in the interest of reducing future issues, I felt the GL-1 that was recommended by Willys was the best choice for me.

The big test will be a year from now when I drain the GL-1 and see if there are brass particles in my oil. �If this happens, I'm not sure what should be made of that.

Happy Jeeping!!


Tim �

[calvinhunt]

Tim,
  I really appreciate your answer.  Now I have another question: When did Willys recommend GL-1? I don't know why we have to been in the dark about such an issue.  We all want what's best.

  When Carl sees this thread again I'm sure he will respond about his reasoning for the 30w opposed to something heavier.

  Thanks again.

[athawk11]

Carl,

Grab a cup of coffee, settle in, and read through this thread on the 2A page. �Time wise, this was about when I was filling my cases with the GL-5 MT-1.

http://www.thecj2apage.com/forums/correct-transmission-fluid_topic19422.html

There is some pretty good information. �Carl will probably remember this discussion. �According to SamCJ2A, he has a 'vintage' Willys manual that calls for 'mineral oil'. �My new bottle of gear oil from NAPA says 'Mineral Oil /GL-1' right on the label.

Happy reading!!

Tim