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75W-80 Gear Oil

Discussion in 'General Truck Info' started by Inane2, Jun 15, 2011.

  1. Inane2

    Inane2 Member

    Hey guys,

    Getting ready to go through my truck (01' Hijet S210P) and change the fluids.

    I've got the gear oil for the differentials no problem (80W-90, GL-5).

    I'm having a hard time finding the recommended oil for the transmission (M/T) and transfer case. The owner's manual calls for 75W-80, GL-4.

    I work part time at night as a fleet mechanic for a large oil company. I've got access to more oil types and viscosities than you can imagine but no 75W-80 in our shop or even stocked in the warehouse. Our fleet uses about 6 different weights of transmission and gear oils. We keep conventional 80W-90 Chevron and the following synthetics : 75W-140, 80W-140, 85W-140, 75W-90 and SAE 50 (all either Chevron RPM, Shell Spirax or Mobil 1). So nothing close to 75W-80 other than the 75W-90. I dug through our oil catalogs and Shell offers a Spirax HD 75-80 but I'd have to order a case to get it.

    What are you guys finding commonly available here in the states? Are you even using the 75W-80? Thanks!

    Jamie
     
  2. Daner

    Daner Member

    When I replaced the oil in my tranny I used Cenex Multi-Purpose Gear Lube 80W-90. It still works fine so I would assume it's okay? idk I'm no expert on transmissions
     
  3. fupabox

    fupabox Well-Known Member

    75-90 synthetic should be fine
     
  4. Stuff99

    Stuff99 Moderator Staff Member

    might want to keep it GL4 though. heard 5 wears out the syncro and fingers in old standards
     
    A. Gillingham likes this.
  5. anthill

    anthill Member

    I had to use Red Line MTL. I don't necessarily trust the boutique brands, but it was the only GL-4 70W80 I could find.

    Shifting is vastly improved over my first half-assed change to 75W90 GL-5 LSD... don't make the same mistake!
     
  6. A. Gillingham

    A. Gillingham Member

    I’m changing mine soon in my 94 Hijet, the main thing of all I’ve learned through my experience is to use a GL3 or GL4. I bought 75W90 GL4/5 as I couldn’t find anything else. As stuff99 said, it’s important that it’s not a GL5 as this will have too much sulphur and potassium which will destroy the yellow metals, like the synchronizes. I’m hoping mine shifts better than it does with this oil change as especially the reverse is hard to engage I find. I don’t know what I’ll find when I drain it but I hope it’s better than the engine oil I found in it. I’ll report how it goes.
     
    Limestone likes this.
  7. Jonno

    Jonno Member

    Hi A', I have a 1999 S210P Dump/lift minitruck that has been stuck at my local garage while I'm out of the country. I've just bought a service manual off lulu to give them the lubricant specs and the volumes required. To shortcut the process, I'd be really grateful to hear what you settled on, with regards to oil change and other fluid quantities.
    Best, Jon (UK)
     
  8. Roadster

    Roadster Active Member

    Redline MTL 75W-80 GL-4 is very good...I am currently running that; It's been -20 here and shifts fine. it probably made about a 15% improvement over whatever they used from the factory... I've used Pennsoil GL-4 Synthetic 75W-80, and Canadian Tire GL-4 75W-80 synthetic in my TR-6 in the past...but my MX-5 definitely shifts better with MTL. As others have stated, don't use GL-5; some gear oils are "buffered" and say they can be used OK in manual transmissions with bronze synchros but better to use GL-4. GL-5 is for the differentials... GL-4 allows for some "sticktion" on the synchros, so they can "pull in to place". GL-5 is too slippery and can make shifting baulky and rough.

    Roadster
     
    Limestone likes this.

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