Question regarding what lube for transmission?.....

[MSeriesRebuild]

the books say run GL4 gear oil in winch, trans, tcase, diffs. GL5 works but is for limited slip diffs with clutches. GL4 I have noticed stays a bit thicker when hot than the GL5 does.

We try to keep up with the most current lubricant technology here at M Series. What we use in both the transmission and transfer case is AMSOIL long run 50 weight synthetic transmission oil, especially designed for this type of gear box, we have had great results. Makes for easier shifting in cold temps, as well as improved flow characteristics which result in better oiling on cold start up, when the major portion of wear takes place. Runs cooler in hot weather, an especially good product in t/cases not equipped with an oil cooling system. I don't know what brands AutoZone offers. Oils meeting this spec are also available in other brands. Be careful of the more "run of the mill brands," many times they claim to meet the same specs., however on the lower end of the allowable limits. The more premium brands offer a much higher quality base stock and additive package, there can be a tremendous difference in overall quality of a product from one brand to another. Cheap price will most often indicate a lower quality product.

In the winch, the best suited product is Worm Gear Oil, what we have now is a Royal Purple product, called SYNERGY WORM GEAR OIL, ISO 460, in warm climate areas, ISO 680 is the better choice. Products that meet this spec are available in numerous brands from industrial lubricant supplier outlets.

In the differentials we use AMSOIL SEVERE GEAR 75W-90 gear lube. This product offers a 500,000 mile service life, so the longevity of this oil is outstanding, as long as your unit is built properly so it doesn't leak, and maintained so water stays out, this oil is there for the long haul.

"THE BOOKS", written back in the 40's-50's when available oils were basically 30 weight for engines and 90 weight for gear boxes, are very much obsolete as far as lubricant recommendations today. Lubricants of all kinds have improved light years since the 50's. Fact is recommendations from "the books" have long since been surpassed in suggesting the best products that are suited for your vintage vehicle.

I hope this helps to clarify things for you, as what you run in gear boxes can and will drastically affect the performance and longevity of the unit.

[RMS]

x2 on that.

check out Ins & Outs of Transfer Case Rebuilds by ashyers http://www.g741.org/PHPBB/viewtopic.php ... 840#p61641 this is what happens when running gl4 in the t case with its limited flow. mmm grey goo
I run chevron 50w synthetic trans oil in trans and tcase...I get almost an extra mpg running the 50w vs 90w

[John_C]

Thank you all for your advice. There is great diversity of opinion regarding oil choice. I just put Rotella straight 30 weight oil in the engine along with a Napa 1100 oil filter yesterday. I'm going to change it again in a couple of weeks to get rid of any left over gunk.
John, Grand Bay, Alabama.

[NAM VET]

I am right at a month out from my Knee replacement, so in the past month, not being able to do much but rest and rehab, I have read all I can on these M 37 vehicles. I think I will be able to handle the pedals on my own M 42 for another month. I have reviewed hundreds of threads on this and other forums, and I have been interested in engine lubrication ever since I got my first car, a '63 TR4 back in college at Nebraska. In the decades since then, I have had a few expensive lessons regarding my lubrication choices.

So, with the disclaimer that I am no petroleum engineer, here is my intent for lubrication choices when I can work on it. For the engine, 10-40 Valvoline, since I live in SC, and don't have to contend with cold start temps, and besides, my motor has a block heater for the occasional chilly morning. I have put in a Baldwin oil filter. By the way, on my former Superformance 427 Cobra replica, I changed all the external oil lines and remote oil filter to larger capacity NASCAR parts off of Ernie Elliot's car, and put in two oil temp gages, one for temps out of the motor, the other for temps coming back to the motor. I am really serious about piston engine lubrication.

In my Tremec in the Cobra, (which I drove for over 140,000 miles!) I tried various oils, and finally got the best synchro function, hot or cold, with a trans lube called BG Full Synthetic SynchoShift. Transmissions and transaxles are finicky things, needing sufficient lubrication yet also requiring thermal and shear stability and especially, synchro friction.

Right now my truck has Royal Purple in the gear box and differential, I am not sure precisely which variations are in each sump. For my truck's transmission, I am going to change it out to Redline MTL, as it is a 50 wt oil, and comprised of the base stock and additives appropriate for this transmission. I have used it before in other gearboxes, and it has always improved the ease of shifting.

For the differential, again, I am going to use Redline's 90 wt gear oil, because it too has good characteristics for the high demand Hypoid diff in my truck, and then too, I have almost a case of it.

By the way, I am going to gradually add a portion of high zinc Redline oil to the engine, and see if the leaks increase as I do so. Since my truck of course has no catalytic converter, I also added some Redline Anti Wear supplement, putting my zinc levels up to about 1500 ppm. And here my truck sits at my son's work garage, down in Columbia, 100 miles from me in Upstate SC. I just can't wait to get to know my truck!!

Have a wonderful Thanksgiving Weekend guys!

NAM VET
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[MSeriesRebuild]

Thank you all for your advice. There is great diversity of opinion regarding oil choice. I just put Rotella straight 30 weight oil in the engine along with a Napa 1100 oil filter yesterday. I'm going to change it again in a couple of weeks to get rid of any left over gunk.
John, Grand Bay, Alabama.

Regarding engine oil that is suitable for flat tappet vintage engines, the category in which the 230 flat head falls; Rotella, Chevron RPM DELO, DELO 400, and other diesel specific oils are no longer a good choice for use in the 230. We used both RPM DELO and DELO 400 for many years, time was these oils still had an acceptable zinc content to satisfy the needs after gasoline engine specific oil types were removing zinc from their additive packages. In recent years EPA mandates have forced almost 100% of the zinc content out of the additive package in these diesel oils too. To get an oil that has a high enough zinc content for proper protection in the 230, we are forced into the specialty oil market. Our choice is AMSOIL Z-ROD, especially blended for older vintage flat tappet engine designs, BUT DO NOT put this in a newly rebuilt engine that has not yet been through a proper break-in period; AMSOIL offers a specific oil for break-in, their recommendation is to run AMSOIL 30 weight break-in oil up to, but not to exceed 1,000 miles after rebuild, then switch to the Z-ROD thereafter. I believe Royal Purple offers a similar product, probably LUCAS and some other specialty lines also offer a suitable product. Since we are now pretty much AMSOIL specific in the products we use, I have not checked out the spec sheets of similar brands lately. As with any lubricant product, cheap and good quality doesn't happen in unison, so I would recommend checking any product you are considering closely to be sure it is completely compatible to your specific engine and needs.

I suggest going to the AMSOIL website, they offer very specific products to consider depending on a given need. For instance, they offer diesel oils specific and labeled in accordance with an engine's year of manufacture. Different tier standards require different oil blends, they still offer oils that meet specs for the older diesels as well as current production engines. I don't know of another lubricant supplier that does that. Most manufacturers offer what they consider a universal product for all. That just doesn't cut it in today's diesel world. You can go to their sight, read detailed specs., and pick out the exact current production product recommended for your specific engine.