Lube Order versus What I Am Told

[glj]

I seriously want to apologize if this has been covered already; I did not read all threads dealing with this issue, as there are so many, and I really did not want to start a new thread. But I think the topic is important because so much of what is being said in this forum regarding the use of GL-1 seems to be contrary to the Lube Orders. I am referring to LO 9-2320-209-12-1, which is the Lube Orders for the M35A2 as well as others. The transmission GO (gear oil) they specify is MIL-L-2105. Well? Every Google search I do identifies this with GL-4 GO and not GL-1. But I've been told that I must use GL-1 to avoid damaging the syncros and bearings with copper and bronze (yellow metal). I know there are additives in GL-4 but only a fraction of what is in GL-5, and I don't know whether any of the GL-4 additives are copper/bronze compatible. Just to be safe I've ordered two buckets of GL-1 90, but I would be curious whether others have noted this apparent contradiction of info.

Also, I've read in this forum that the transfer case also has yellow metal. Assuming this to be the case, I would ask whether the differentials also have heavy metal. If so, it would be easy; use GL-1 everywhere (unless the LO
truly means GL-4, as my research seems to indicate). Check it out. If you have that LO confirm yourself that it calls for MIL-L-2105; and confirm that this is GL-4. I'm confused, but always appreciate simplicity.

In my particular case I have ASB air lockers in all 3 axels and I suppose I should address that hardware lube issue as well, but that is beyond my current question.

Any comment?

Sincerely,

Gary

 

[cattlerepairman]

In short, this topic has been exhaustively covered in the past. People will probably tell you to search for it.

I try to sum up what appears to be recurring consensus:

Lubrication technology has moved on since the time the LO was published. Today's GL-5 is generally seen as yellow metal safe, even if it is not explicitly written on the container. Often, checking data sheets online will reveal a statement on yellow metal safety.
Many GL-05 products also carry a MT-01 rating, in which case they are ok to use in the transmission.

I know that there are discussions on how 30W engine oil is the lubricant to use in the transmission, and, in the end, you need to decide what you put into your truck.

My personal experience is exclusively with Valvoline 80W90 GL-05 in axles, transmission and transfer case, with smooth shifts and no issues.

 

[gimpyrobb]

Yup, use any gl-4 or gl-5 that is yellow metal safe. I will be swapping to 30wt oil in my trans soon to see how it does.

 

[Westech]

I use 80/90W in the axles, and T case but have switched to 30W ND motor oil in the trans. I do not notice any difference.

 

[doghead]

I noticed an increased ability to hit reverse, shifting out of first, in Westys truck with 30W in his trans.

 

[Westech]

You drove my truck?

 

[doghead]

No, I rode in the back.

 

[Westech]

was I drunk ?

 

[doghead]

Yes

 

[Westech]

Ah. Anyway as the lube goes.. use what you want to. It seams that the gear oil has worked for almost 60 years. But you do have choices.

 

[Flyingvan911]

Look for the "MT-1" rating for yellow metal safe lube. SS has it's own private civil war over which lube is best.

 

[SSG Rock]

I agree with everyone before me, the LO was written well before the new GO was put on market, the military changes as the market changes, when your engine was new it came with SAE 30 but was changed to 15W40 many years later, same goes with other fluids.

 

[dmetalmiki]

My Usage

Engines. OMD 110 or 330 everything else OMD 220. (uk) british military oils.

 

[tco3129]

I use a NAPA GL 5 with a MT 1 rating