What fluids do you guys run?

BlitzAttack · Post by **BlitzAttack** » Mon Aug 30, 2010 8:47 pm

Just curious what fluids are safe to run in my 53 m38a1?

Engine-
Transfer Case-
Tranny-
Diffs-

Thanks
Casey

Post by **wesk** » Mon Aug 30, 2010 10:49 pm

Engine- I prefer straight weight detergent oils.
Transfer Case- Any quality 80/90 GL1-4 GO gear oil works fine. So does straight ear oil and heavy engine oil.
Tranny- Any quality 80/90 GL1-4 GO gear oil works fine. So does straight ear oil and heavy engine oil.

Diffs- Any quality Hypoid gear oil.

These aren't HiPo engine and drive trains. They do not require any fancy stuff. They do like to have what you do use changed at least 3000 miles or twice a year.

TomM · Post by **TomM** » Tue Aug 31, 2010 6:28 am

Engine oil - If you run a search on the topic you will find many responses with just as many opinions with some giving technical pros and cons.

Trans and transfer - Per Wes GO recommendation, note he did not say GL5 Hypoid. In some areas finding standard GO is difficult unless you purchase a 5 gallon pail.
The problems reported with GL5 Hypoid 80/90 come in if they have additives that attack soft parts (synchro rings and thrust washers). Again, do your research on this one as there are those who agree and disagree as to the validity of this claim. The MT1 rating on some GL5 supposidly means it is compatible for manual transmissions.

NAPA GL4 MTF specifically has labeling that it is compatible with older running gear. I run it in transmissions and transfer cases.

Tom

Post by **wesk** » Tue Aug 31, 2010 12:28 pm

Tom is right on. No GL-5 hypoid oil in the tranny/transfer.

I have an M37 as well and from the M37 web site here is a quote from Charles Talbert of M Series Rebuilds. Keep in mind I am not promoting him or his business and I actually do not often agree with him but he is right on the spot with these comments:

Actually gear lube oils that you mentioned should only be used in the differentials. GL5 in an 80-90 grade is good there, however there are premium grade oils that are MUCH better than the over the counter stuff at Wal-Mart. Royal Purple is top of the line, their product is called Max Gear.

The transmission and transfer case will be much better served by using a 30,40,or 50 weight straight grade engine oil. This is in accordance with the ambient temp at your location, the 30 weight in cold climates, 40 in moderate climates, and 50 in warmer climates. Most of ours get either 40 or 50 weight. Again my top recommendation would be Royal Purple engine oil in the appropriate weight grade. You will immediately enjoy better shifting and better lubrication of your components, especially in cold weather. Oil is very different these days than it was when the manuals for the M37 were printed. Technology has come a LONG WAY since then.

Keep this in mind when searching for lubricant sources, the old line "you get what you pay for" has never been more true than it is today. Cheaper oils of today are extremely poor quality products, the old names you've heard for years are nothing more than a name these days. Good quality lubricants are expensive, cheap stuff is too, in more ways than one.

Pouring top $$ oil in a component that is worn out or has issues is not a miracle fluid. FIX ANY ISSUES up front. Pouring top quality oil in a component that is in top notch condition will save you money all day long. You will enjoy a much longer trouble free life from your components as a result of using good lubricants.
Charles Talbert
www.mseriesrebuild.com

captw · Post by **captw** » Wed Sep 01, 2010 11:40 am

I use Kendall TransGard 50 in my jeep...it shifts better, and is supposed to run cooler than with the 80/90 oil...only drawback is that it seems to seep out easier...Wilf

Cacti_Ken · Post by **Cacti_Ken** » Wed Sep 01, 2010 8:06 pm

I think the Mobil 85-140 wt GL-5 MT-1 gear oil I've been using is eating something in my gear boxes. The oil looks like it has glitter in it.
Real fine particles of brass and steel. Even though it says can be used in some manual transmissions.

Cacti_Ken · Post by **Cacti_Ken** » Wed Sep 01, 2010 9:24 pm

I read on some oil at Wal-Mart that said good for GL-5 service, EP, Extreme pressure. This was the only oil they had on the shelf.

Is this Hypoid gear oil?

53a1 · Post by **53a1** » Wed Sep 01, 2010 10:59 pm

Crap,

I better get the Coastal lube out of my tranny asap

Balvar24 · Post by **Balvar24** » Thu Sep 02, 2010 6:06 am

My understanding is that GL4 is what you want for transmissions with yellow metals in them. When I rebuilt the T-150 in my CJ7, all I could find locally was some Royal Purple and Shell Syncro-Mesh.

53a1 · Post by **53a1** » Fri Sep 03, 2010 2:16 pm

I dropped the drain plugs before I left town. I'm going to let the GL5 drain out for a few days then put in the correct fluid. I've only had the GL5 in for a few months so hopefully my synchros are not disolved.

At least they will be nice and shiny now

Niclas · Post by **Niclas** » Sat Sep 04, 2010 1:55 am

Engine, Transfer Case & Tranny 10/30 engine oil

Diffs Hypiod Oil

/Niclas

skyjeep50 · Post by **skyjeep50** » Sat Sep 04, 2010 9:46 am

This may help clear things up (or muddy the waters). I'm returning the GL-5 oil I just bought, have used GL-4 with good results in my M38A-1, that's what the lube chart calls for.
http://en.wikipedia.org/wiki/Gear_oil

Cacti_Ken · Post by **Cacti_Ken** » Sat Sep 04, 2010 7:16 pm

I thought differential gear oil and maunal transmission gear oil and transfercase gear oil was all the same. And is why I used the Mobil 85-140 wt GL-5 in all boxes. Unaware that it would cause brass to ware faster. It says on the spec it can be used in some manual transmissions. However I guess not our jeep Trannys and T/C's.

I found these words on a site for Mitsubitsi manual transmission oil.

Use of GL-5 spec gear oil isn't recommended in your manual transmission except for certain conditions. The EP (Extreme Pressure) additives found in GL-5 may reduce the effectiveness of your synchronizers making the transmission shift poorly and tarnish them over time. However, it should also be noted that if you are wanting an oil that does provide higher film strength and added protection against gear & bearing wear, you may consider using a GL-5 spec gear oil. Just remember that it will not shift as good at the high rpms and that it will oxidize the synchros over time

I guess syncronizers are made of brass????

Post by **wesk** » Sat Sep 04, 2010 8:05 pm

The synchro's will suffer an early death with hypoid oil.

80/90 weight is too heavy for the tranny and causes greater shifting effort.

skyjeep50 · Post by **skyjeep50** » Sun Sep 05, 2010 10:55 am

Posted: Tue Aug 31, 2010 2:49 pm Post subject:

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Engine- I prefer straight weight detergent oils.
Transfer Case- Any quality 80/90 GO gear oil works fine.
Tranny- Any quality 80/90 GO gear oil works fine.
Diffs- Any quality Hypoid gear oil.

These aren't HiPo engine and drive trains. They do not require any fancy stuff. They do like to have what you do use changed at least 3000 miles or twice a year.

Posted: Sun Sep 05, 2010 12:05 pm Post subject:

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The synchro's will suffer an early death with hypoid oil.

80/90 weight is too heavy for the tranny and causes greater shifting effort.

Motor Oil and Gear Oil have different SAE viscosity scales. 80/90 Gear Oil is about the same viscosity as 30/40 Motor Oil. See http://www.teamrip.com/viscosity_chart.html
I think the statement "never substitute SAE Crankcase Oil for SAE Gear Oil" is significant. Logic would follow that motor oil and gear oils are made to different standards. Hypoid differentials and transmission/transfer gears are different but GL-4 oils will work for both.

What fluids do you guys run?

What fluids do you guys run?

lube

transmission/transfer case lube

Hypoid Gear Oil Info