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T-90 fluid fill issues

Discussion in 'Early CJ5 and CJ6 Tech' started by Leathernek, Jan 18, 2013.

  1. Leathernek

    Leathernek Member

    Hey guys,

    I've got a '63 CJ5 with the F134/T90 setup. The problem I'm having is that my HAYNES manual doesn't tell me is where the tranny or transfer case fill is. I assumed the transmission fill is on two plugs on the drivers side (upper and lower) and the transfer case is on the passenger side. Funny thing is when I opened what I assumed was the transer case drain on the bottom through the skid plate, fluid came out, but I hadn't filled the transfer case yet, only the transmission. So either that is the transmission drain or my tranny fluid is seeping over into my transfer case? I don't know. BTW this transmission has been fully rebuilt. So my question is- Is the tranny fills on the driver's side and transfer case on the passenger? And what is that bottom plug to? Any help is appreciated!

    Sincerely,

    Confused (aka Leathernek)
     
  2. nickmil

    nickmil In mothballs.

    The fill plugs are about halfway up the cases on both the transmission and transfer case. Transfer case is on the passenger side. Don't remember on the T-90 but should be obvious. Drain on the transfer case is directly on the bottom of the pan and you reach it through the skid plate as you noted. Drain on the transmission is on the bottom but sticks out sideways from the transmission case. Lube flows between the T-90 and 18 transfer case.


    Sent from my iPhone
     
  3. Leathernek

    Leathernek Member

    Thanks for the help! You said, "Lube flows between the T-90 and 18 transer case." Does that mean that they both take the same lube? If so, what is it? Because I believe that my haynes manual has failed me again! :/ (It says the tranny takes 75-90 and the transfer takes 80-90)
     
  4. nestle105

    nestle105 New Member

  5. Leathernek

    Leathernek Member

    So do they both take the same fluid?
     
  6. nestle105

    nestle105 New Member

    Yes that is correct
     
  7. uncamonkey

    uncamonkey Member

  8. ziv

    ziv Member

    anyway you should fill each one. that is what i do ...
     
  9. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Yes, don't depend on the oil sharing for filling. Transfer rate is slow.
     
  10. Glenn

    Glenn Kinda grumpy old man Staff Member

    The fill plug on the transfer case is lower than the T-90 transmission fill plug. Oil sharing in this case can't logically happen. There is a passage hole between the transmission/t-case that is above the oil levels.
     
  11. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Well, there's no seal on the bearing, so oil goes through the bearing too.

    From previous discussions, I recall that the transfer case ends up "overfilled" after a while - becasue of the difference in the fill plug levels. But it does not seem to hurt anything.
     
  12. Glenn

    Glenn Kinda grumpy old man Staff Member

    I remember those same discussions. I haven't had the same problem however, so I myself am confused by all of this.
     
  13. Warloch

    Warloch Did you say Flattie??? Staff Member

    They 'can' become over filled - a lot of that depends on the angle things are sitting in the drive train. It is also why there is a vent on the top of the D18.
     
  14. Leathernek

    Leathernek Member

    Thanks for the help guys- I went with GL5 80-90 in it.
     
  15. I'm pretty sure GL5 is a no-no???
     
  16. danielbuck

    danielbuck Uncle Buck

    I'm not sure if the T-90/D-18 in your Cj5 has the same metal types on the insides as my my CJ2a (also with T-90 and D-18 ), but putting GL5 in the transmission/transfer case of a 2a is apparently very bad due to the types of metals on some of the transmission parts. There was a nice thread on this a while back on The CJ2a page. I don't want to try and drive traffic away from these forums, but there seemed to be some good information there. The end result, was to use GL-1 Mineral Gear Oil, after folks asked several oil companies. If you'd like to see the discussion, it's here in the link below. But the result, was to use GL-1. Most folks ended up getting it from Napa in 1 or 5 gallon pails.

    http://www.thecj2apage.com/forums/correct-transmission-fluid_topic19422.html

    I ended up getting a 5 gallon pail of the 90w GL-1 MINERAL GEAR OIL from Napa. I went through two cheap hand-held pumps that just were junk, one of them wouldn't even pump, the other exploded on me (both apparently were supposed to work with Oil). So I tossed those cheap plastic pumps and got a good metal one that replaces the entire lid of the pail, and it works like a charm. Checking the fluid level in the 2a is no longer a chore anymore :D
     
    Last edited: Jan 25, 2013
  17. Don X

    Don X The Prodigal Moderator Staff Member 2023 Sponsor

    It wasn't specifically stated so I apologize if I'm stating the obvious. Because the fluid can flow between the units, fill the TC first.
     
  18. PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    There was a long thread on this site too, regarding GL ratings and sources for the right kinds. Just a couple of weeks ago.