Manual transmission fluid

Discussion in 'Transmissions' started by Illsley1983, Mar 12, 2018.

  1. Illsley1983

    Illsley1983 Newbie

    Messages:
    19
    Likes Received:
    2
    Joined:
    Feb 16, 2018
    Location:
    New Brunswick
    hey everyone,

    What type of fluid does my transmission take? I just had it rebuilt and they gave my 80w90 for the transmission and atf for the transfer case. My transmission is an hm290 or 5lm60. Just spent a lot of money getting this built and I want to make sure I put the right stuff in it.
     
  2. Illsley1983

    Illsley1983 Newbie

    Messages:
    19
    Likes Received:
    2
    Joined:
    Feb 16, 2018
    Location:
    New Brunswick
    Called GM and all they could tell me was "manual transmission fluid".
     
  3. someotherguy

    someotherguy I'm Awesome

    Messages:
    3,830
    Likes Received:
    1,023
    Joined:
    Sep 28, 2013
    Location:
    Houston TX
    So you've got the light duty 5 speed (HM290, 5LM60, NV3500, etc.) - in other words straight 1 thru 5, no granny low 1st gear. It takes ACDelco "Syncromesh Transmission Fluid" which is part # 88900333 - dunno the specifics on it such as weight or GL-specification though. Lots of people offering Syncromesh style fluid so go with a brand you trust.

    If you had the heavy duty 5 speed (NV4500) with granny low, it would take GM's "Synthetic Manual Transmission Fluid" which is part # 12346190, a 75W90 GL-4 fluid. It's re-labeled Castrol Syntorq LT that I haven't seen available from Castrol in their own label (though I can find a picture of it online, lol!) - it's also sold by Dodge as part # 4874459. This fluid is mandatory for the NV4500 due to the special syncros in it.

    Richard
     
    DerekTheGreat and df2x4 like this.
  4. DerekTheGreat

    DerekTheGreat I'm Awesome

    Messages:
    428
    Likes Received:
    104
    Joined:
    May 23, 2016
    Location:
    Michigan
    My truck has the 5LM60 in it and let me tell you, I had a shop change the fluid and they put gear oil in it.. Shifting when below 50 degrees F was nearly impossible. Had to hunt for the GM Syncromesh like mentioned above and when it went in there, much much better. Side note: 1st gear in this thing sucks 4.00:1, nearly useless with 3.73's out back. But 2nd seems too steep to start off in.
     
  5. someotherguy

    someotherguy I'm Awesome

    Messages:
    3,830
    Likes Received:
    1,023
    Joined:
    Sep 28, 2013
    Location:
    Houston TX
    From what I can find, and it's not definitive - Syncromesh fluid is similar to a 5W30 in weight. If that's true, using 80W90 in place of it would be a really bad choice. IMO.

    Richard
     
    Oldblue98 likes this.
  6. Illsley1983

    Illsley1983 Newbie

    Messages:
    19
    Likes Received:
    2
    Joined:
    Feb 16, 2018
    Location:
    New Brunswick
    Thanks guys. Everything I have read online says not too use 80w90. I'm assuming the read something wrong when they looked this up. You would think a transmission shop would know this. I am going to return it and go to GM and get the proper fluid.
     
  7. DerekTheGreat

    DerekTheGreat I'm Awesome

    Messages:
    428
    Likes Received:
    104
    Joined:
    May 23, 2016
    Location:
    Michigan
    Never assume lol. Look at what the shop manual says and if the original fluid isn't available there is typically info out there regarding what supersedes it.

    @someotherguy: Yeah I got that stuff out of there pronto. I didn't notice anything when I picked my truck up from their shop but the following morning, holy hell it was as if my slave cylinder was bad or something. Either lube wasn't getting where it needed to be or it was TOO good of a lube. I dunno, need an engineer's opinion on that one. Kinda leaning to the too good side personally.
     
  8. Oldblue98

    Oldblue98 Supporting Member

    Messages:
    446
    Likes Received:
    282
    Joined:
    Dec 27, 2017
    Location:
    Gulf Coast Florida
    You would think a transmission shop would know a lot of things.. The thing they know most is cash or credit card !
     
  9. Illsley1983

    Illsley1983 Newbie

    Messages:
    19
    Likes Received:
    2
    Joined:
    Feb 16, 2018
    Location:
    New Brunswick
    Apparently, when they called carquest for fluid, that is what carquest gave them. It was GL4 80w90 gear oil, which is used in the heavy duty 4 speed and heavy duty 5 speed. There must have been some confusion when they called them. anyways, I took it back and got the right stuff from GM.
     

Share This Page