How to change your transmission and transfer case oil

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Spike
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How to change your transmission and transfer case oil

Unread post by Spike » February 28th, 2008, 9:37 pm

How to change your transmission and transfer case gear oil.


I normally do a major service every three-years on my A1. That includes changing all the fluids, repacking bearings and greasing everything. I do a minor service once a year lube / oil / filter. You need to decide what your service intervals are, based on the use of vehicle. The military "S" preventive-maintenance services were performed every six-months or 6,000-miles. The LO TM mandates transmission/transfer case gear oil change at 24,000 miles or 24-month whichever comes first. I don't service my POV's but I do my 151 because I want it done right and there is a pitfall.

If you're going fording or into deep water it would be prudent to change all your fluids right afterwards because water will find its way into places you don't want it. If you find water in your transmission while draining the fluids you are going to want to flush it to insure that all the water is out. This is normally done with solvents.

The first thing I do is put on rubber gloves, old clothes and shoes that I can toss in the trash afterwards.

I change the oil when it's hot, not because I like burning my fingers, but they drain better and some sludge and particles become suspended in the gear oil.

The transmission holds: 2 and 3/4 quarts. (2.6litres)

The data plate and TM's (LO9-2320-218-12) recommend:
Temp above 32f; GO-90 {GO85/140 ~not recommend in the 1966 or 1988 LO}
Temp 40f to -10f; GO-80 {GO85/140~ not recommend in the 1966 or 1988 LO}
Temp 0 to -65f; GO75 {some, older data plates and TM's have this as GO5}

Lubrication Order link:
http://www.pedros.cz/M151/LO_9-2320-218-12_Jul78.pdf
http://www.pedros.cz/M151/LO_9-2329-218-12_Jul88.pdf
http://www.pedros.cz/M151/LO_9-2320-218-12_Nov66.pdf

The transmission and transfer case are machined and matched set that are married. There are two drain plugs. One is in the transmission and one is in the transfer case. The plug heads are 1 1/8". There is a second plug in the transfer case. That is the "clutch shifter detent plug" it holds a spring and ball in place. The head is much smaller (7/8") and in goes into the transfer case at an angle. It won't hurt anything to take it out and clean and check it (so long as you don't lose the spring or ball) the are two *plugs* on the side of the transmission, one is the "oil level fill plug" The other looks like a fill plug BUT IT IS NOT. It's a shifter arm pivot pin and it's a bit of a headache if you remove it because the shifter arm will fall into the bottom of the transmission.

I remove both drain plugs and let it drip into a pan. I check for metal particles in the fluid.

Clean magnets and reinstall the plugs. It's nice to replace the plug washers if you can. Tighten the plugs to: 10 to 14 foot pounds, (per TM 34-1)

I use the pump-type gear oil container, because it's too hard to squirt it in with the typical bottles. I fill it until it starts to overflow.

Check and clean the transmission breather valve at the top of the tranny in front of the shifter boot.



Image These photos show some of the different types of fill and shifter arm heads


Image

Image

Image

ImageSpike,

Now that you have that stinky gear oil on your hands, floor and clothes you might as well do your differentials. Once I'm done I just throw away any clothes that I get gear oil on.

There is a lot of talk about putting in a heavier weight gear oil to "quiet the tranny" (and differential.) The people who have tried this report no noticeable sound reduction. Without getting into a lecture on lubrication, the best path to take is to use only what is specified for your differential and transmission.

I personally am not big on additives either. But that's a personal thing.
http://www.bobistheoilguy.com/images/lucas/lucas.htm
As iron sharpens iron ...

k8icu
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Unread post by k8icu » February 28th, 2008, 10:32 pm

Throw away your cloths? What you don't dab a little of 90W behind your ears for cologne? Gotta love that smell.... :)

Great post might help some new owners and keep them from having a headache!
There is one nut on a M151 that is very difficult to remove.....

toptiger
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Unread post by toptiger » February 28th, 2008, 11:24 pm

thanks, spike for posting this- great info
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Ralph Fuller
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Unread post by Ralph Fuller » February 29th, 2008, 12:02 am

Thanks, Spike. I appreciate you taking all of the time to put this information together.
Ralph
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Spike
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Unread post by Spike » February 29th, 2008, 11:54 am

k8icu wrote:Throw away your cloths? What you don't dab a little of 90W behind your ears for cologne? Gotta love that smell.... :)

Great post might help some new owners and keep them from having a headache!
Thanks, I know the average guy can figure out how to change his tranny oil. The biggest and most frustrating mistake is pulling the wrong *plug*. Been there, done that.

Back in the 70's I ended up living in a congested metropolis area. Being a country boy at heart I wasn't too wild about it. We were living in this nice townhouse. Just outside my window was a sidewalk and there was a concrete transformer box (underground utilities) that stuck up about 20-inches. People would stop and sit there at all hours of the night like it was a park bench. It would drive me crazy, careless people carrying on drinking, talking in loud voices. I was forever picking up their trash, and yelling at them through the window to no avail. One day I had a brilliant idea. I took a quart of 90w gear oil and poured it all over this transformer lid. Wasn't long and nobody sat there. I'm sure I ruined a few peoples trousers. Every so often I'd go out and give it a squirt. Kind of like a mosquito repellent. :lol: :lol:
As iron sharpens iron ...

Floyd
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Unread post by Floyd » February 29th, 2008, 12:32 pm

Super info Spike, thanks.

Floyd
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raymond
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Unread post by raymond » March 5th, 2008, 10:48 am

Spike

I grew up working at the family oil company. I learned over the years that the best way to get rid of offensive petroleum smells such as hypoid gear oil or diesel fuel is to wash the tainted work clothing first with a cup of Pine-Sol. Then wash with regular detergent. Your clothes will smell like a pine forest for a wash or 2 but it beats throwing out an otherwise good shirt or pair of pants.
Raymond


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Spike
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Unread post by Spike » March 6th, 2008, 10:57 am

Raymond, if I went near my wife's washing machine with gear oil soaked clothes and a bottle of Pine sol she'd hit me with something :lol: Sounds like a good tip, thanks.
As iron sharpens iron ...

Miltrans
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Re: How to change your transmission and transfer case oil

Unread post by Miltrans » April 21st, 2008, 5:01 am

Hi

On the oil subject, just wanted to help others from paying for the same experience that us other mortals have had to pay good money and many tears for.

The oil used in the gearbox is not to have an higher GL value than GL4. Many of our guys (me included) have thought that we did a good deed when buying expensive SAE 80 - 90 GL5 modern oil for our gearbox. Some time afterwards when the gearbox started to fail in the synchromesh between gears we could not understand.... until we drained the oil ...... pure gold coming out the drainhole !! ..... eh, no ! not gold but bronze.
First to go is the synchromesh, then the end thrust plate and lastly the drive for the speedometer.

So when buying "civi" oil for the gearbox get some of "the good ol' stuff". DIfferentials shold be ok with the GL5 though, but why waste the money and also have the chance of a mix-up later?.

One of the poor guys said that it was just like when he bought a beutiful blond an expensive ring. Not long afterwards she draind him of all his gold, and left him in tears!!
Chris

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raymond
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Re: How to change your transmission and transfer case oil

Unread post by raymond » April 21st, 2008, 6:55 am

Some GL5 gear oils are okay with non-ferrous metals. They contain a buffering agent that protects brass/bronze/copper from the corrosive effects of the sulfur compounds used in the high pressure additives.
Raymond


"On the day when crime puts on the apparel of innocence, through a curious reversal peculiar to our age, it is innocence that is called on to justify itself." Albert Camus

Miltrans
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Re: How to change your transmission and transfer case oil

Unread post by Miltrans » April 22nd, 2008, 4:22 am

Hi Ray.

Interesting, could you tell us how these "non-destructive" GL5 oils are marked? or is there a specific make ?

Sometimes when you need to top-up or have had that BLOB experience when the driveshaft ´comes out unexpectedly, these things always seem to happen on a day that the stores are closed and you have just given your last quart of gear oli to a friend.
Could be nice to know which brand to go for at the gas station.

Chris.

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raymond
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Re: How to change your transmission and transfer case oil

Unread post by raymond » April 22nd, 2008, 9:11 am

Sometimes it says on the bottle that it is safe for brass or non-ferrous metals. If not, see if there a phone number on the bottle for the manufacturer. You can call and see if it is safe, or if they have a safe alternative. Or you can always use GL 4 oil. They are even available in a synthetic version.
Raymond


"On the day when crime puts on the apparel of innocence, through a curious reversal peculiar to our age, it is innocence that is called on to justify itself." Albert Camus

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