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Thread: transmission oil discussion

  1. #1
    Join Date
    Jul 2009
    Location
    Jacksonville, FL
    Posts
    18

    Default transmission oil discussion

    I am almost done rebuilding by T-19 and my Dana 20, and I am trying to decide what type of oil to put in them.

    Does anyone have a link to a good link to the 80w90 vs 20w50 vs 40w vs 50w discussion. I have searched here but did not find anything (maybe I am search retarded or something).

    I have seen a few random statements on some of the jeep forums, but I am wondering if anyone has ever seen or written a good technical discussion of this.

    I bought the rebuild kits from Novak - their website says 90 weight gear oil (AP GL 5) is the manufacturer recommendations, but that use of 50 weight engine oil is "not contraindicated." Sounds like lawyer-speak more that a real statement to me.

    Also, does this apply to the transfer case as well as the trans, or just the transmission?

    I want max life and good performance, I am not looking to squeak out any extra performance at the cost of accelerated wear and tear.

    Thanks!

  2. #2
    Join Date
    Feb 2009
    Location
    Aiken, SC
    Posts
    2,423

    Default

    Quote Originally Posted by --james-- View Post
    I am almost done rebuilding by T-19 and my Dana 20, and I am trying to decide what type of oil to put in them.

    Does anyone have a link to a good link to the 80w90 vs 20w50 vs 40w vs 50w discussion. I have searched here but did not find anything (maybe I am search retarded or something).

    I have seen a few random statements on some of the jeep forums, but I am wondering if anyone has ever seen or written a good technical discussion of this.

    I bought the rebuild kits from Novak - their website says 90 weight gear oil (AP GL 5) is the manufacturer recommendations, but that use of 50 weight engine oil is "not contraindicated." Sounds like lawyer-speak more that a real statement to me.

    Also, does this apply to the transfer case as well as the trans, or just the transmission?

    I want max life and good performance, I am not looking to squeak out any extra performance at the cost of accelerated wear and tear.

    Thanks!
    James-

    GL5 eats yellow metal. Do not use it in your transmission or transfer case.

    50 wt synthetic is probably the best thing you can use. 50 wt motor oil has the same viscosity as 90 wt mineral (gear) oil. If you live in a cold climate, you can use 20w50 with no problem at all.

    Break it in for a few thousand miles with 20w50 motor oil, then swap in synthetic.

    If you don't have a magnetic oil drain plug, buy one, or go find one in a transmission on an old dump truck at a junk yard. Worth their weight in gold.

    All of this is true for the Dana 20 t-case as well.

    Here is my friend Eldon McFarling's synopsis on the issue. Eldon could fix the space shuttle with a feather and a jar of peanut butter. There is nobody on the planet with whom I would rather be when I was broke down. He owns a diesel repair shop and runs a trucking company from his farm in Nebraska.

    Quote Originally Posted by Eldon

    > Re: Transfer case oil and a followup ????
    > Eldon McFarling -- Thursday, 2 July 1998, at 6:
    > 38 p.m.
    >
    > Michael,
    >
    > let me try to explain a little more about tranny & transfer case
    lubrication.
    > First off while IH publications are very good in general, the
    > lubrication information is often outdated. Also since the lubrication
    > section covers everything from Scout's to over-the -road trucks it
    > can be confusing, and inaccurate sometimes.
    >
    > Synchronized manual transmissions, and transfer cases require lighter oil
    > for lubrication because they have less clearance between
    > major parts, such as synchronizers, gears & shafts, etc.. Heavier gear oils
    > cannot provide adequate lubrication between gears and
    > shafts since it will not flow thru small passages, or tight clearances.
    Gear
    > oils can also make shifting difficult, or impossible in cold
    > temperatures. Gear oils with EP addatives ( the type used in driving axles)
    > are especially bad when used in transmissions because
    > the EP addatives can plug passages that the lubricant has to flow thru, and
    > can also build up on other parts such as synchronizers,
    > and sliding clutches, causing early failure. Another benefit from using
    > engine oil is that the detergent addatives in the oil keep the
    > inside of the transmission clean.
    >
    > For all Warner transmissions, Dana model 20, 300, & New Process transfer
    > cases, heavy duty engine oil SAE 50 should be used,
    > and will perform well in all normal climate conditions. (from -0 deg. f. to
    +
    > 100 deg. f.). For extremely high temperatures (above +100
    > deg. f.), synthetic oil should be used. For extremely cold temperatures (
    > below -0 deg. f.) SAE 30, 40, or multi-grade oil can be used.
    > Dana model 18 transfer cases can use SAE 50 engine oil, or a heavier SAE
    80-
    > 90 mineral gear oil to reduce gear whine at higher
    > speeds.
    >
    > IH built 5 speed transmissions T-34, T-35, and T-36 require mineral gear
    oil,
    > R&O type, SAE 80-90. I believe SAE 50 engine oil, or
    > synthetic engine oil will work satisfactorily also. IH built 5 speed
    > transmissions T-494, T-495, and T-496 MUST USE SAE 10-30, or
    > SAE 10-40 multi-grade engine oils. [there is a zinc addative that should be
    > used in the T-495, T-496 to reduce wear on the shift forks]
    >
    > To sum it up gear oils with EP addatives should not be used in synchronized
    > transmissions. Mineral gear oil can be used in some
    > applications, but it may not provide adequate lubrication in some cases,
    and
    > is harder to find. SAE 50 engine oil should be used for
    > most transmission, and transfer case lubrication for all IH Scouts, and
    > light trucks. Older, non synchronized transmissions should
    > use mineral gear oil.
    >
    > Eldon McFarling
    >
    > THE SCOUT DIESEL PAGE
    Allan E.
    Curmudgeon Extraordinaire
    Charter Member, Old Hippie IH Club
    Old fashioned binder freak

  3. #3
    Join Date
    Jul 2009
    Location
    Jacksonville, FL
    Posts
    18

    Default wow, thanks

    Allen, thanks for passing on the excellent info. Much appreciated.

    As far as the magnetic plug, my transfer case has one, but my transmission did not. There is a magnet in the bottom of the case, but it is only accessible with the passenger side PTO cover removed.

    My local CSK sells magnetic drain plugs, and they just happen to fit my tranny and engine oil drain plugs. I noticed that the transmission magnet has quite a lot of metal filings, but I can't see any single source for the metal. All of the gears appear to be in decent condition - there is some visible scratching on most of the gear teeth, but it appears to be even wear with no scoring or chips. All of the scratches are too fine to feel with my finger or fingernail, but they are definitely visible. It kind of looks like shiny metal after you run some 00 steel wool over it.

    I am just surprised to see how many filings have accumulated on the magnet. The transfer case did not even come close to that many filings.

    Anyway, thanks again
    Last edited by --james--; 09-06-2009 at 03:03 PM.

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