Fuller transmission oil

Discussion in 'Ask An Owner Operator' started by Bkadds, Oct 19, 2014.

  1. Bkadds

    Bkadds Bobtail Member

    11
    1
    Oct 11, 2014
    0
    Book says 80 wt mineral oil. I have mystik 80w-90 jt7. Will this work? What does mineral oil mean? Thanks
     
  2. Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.

  3. heavyhaulerss

    heavyhaulerss Road Train Member

    3,723
    2,038
    Dec 23, 2009
    AL/TN BORDER
    0
    the mystic 80w=90 is gear oil. all trans I know of in big trucks use 50 wt. mystic also has it's own 50 wt. I do not know what they mean by 80 wt min oil either.:dontknow:
     
  4. Bkadds

    Bkadds Bobtail Member

    11
    1
    Oct 11, 2014
    0
    Book says straight mineral gear oil of sae 90 above 10 degrees f. Not sure either. This is on a 1968 freightliner.
     
  5. xsetra

    xsetra Road Train Member

    4,907
    6,539
    Aug 21, 2011
    0
    Mineral oil (usually a crude oil base) or synthetic.
     
  6. baha

    baha Road Train Member

    4,137
    2,832
    Jul 25, 2013
    ga
    0
    That info. is old, pull out a cup of what comes out of trans. and look at it red or light color is syn. type oil, mix the new oil in with the old oil in your cup if it mixes your or good to use the myst. 80/ 90wt. you bought.
     
  7. Old Man

    Old Man Road Train Member

    4,597
    13,466
    Apr 3, 2009
    Oklahoma City, OK
    0
    There wasn't any 50w synthetic in 1968.
     
  8. Bkadds

    Bkadds Bobtail Member

    11
    1
    Oct 11, 2014
    0
    I drained a bunch of water followed by pitch black oil. There is no telling what was in there.
     
  9. baha

    baha Road Train Member

    4,137
    2,832
    Jul 25, 2013
    ga
    0
    OK. might be better to put in some cheep 90wt. run around till till trans gets warm to your touch then drain it again before you put in that hi $ mstic gear oil just to be sure all that oil/water mix is drained out, ck the veht on top of trans to see if it got broken off an is letting water in thru hole in top of it?
     
    jbatmick Thanks this.
  10. harleyhead

    harleyhead Bobtail Member

    44
    5
    May 28, 2013
    0
    back in the 60,s and some 70,s many transmissions used what we called mineral oil which was entirely different from other transmission lubes my advice if u don't know for sure whats in it or can no longer buy it just drain it and change it to 90wt gear oil but do not mix it
     
  • Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.