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Rear Differential Fluid Change on Prius AWD

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by ColoradoBoo, May 27, 2023.

  1. ColoradoBoo

    ColoradoBoo Senior Member

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    Since my 2021 Prius LE AWD just went over 25,000 miles, I decided to change out the fluid in the rear differential. (Every 3-years or 25,000 is my rule.)

    In comparison to the rear diff in my Tundra, the only thing similar is that it has a drain plug and a fill plug...amount of fluid and fluid type isn't the same.

    Tools: Two crush washers (90430-A0003), a 10mm Hex socket (a short one is better but you can manage with a regular one), and 2 Qts of Toyota WS transmission fluid. (You'll use about 1.4 Qts) A pump to refill the fluid or a funnel with a long hose, which is what I did since I hate those pumpers.

    Get the car up on jacks or a lift, needs to be level. Remove fill plug which is on the passenger side and a bit hard to spot...not a lot of room in there. I used my 3/8 socket with a short extension. (The 10mm bolts can strip pretty easy to make sure you have it seated in there very good before cranking on it.) Then remove the drain plug on the other side, a bit lower, and drain all of the red transmission fluid. Note: Toyota must have gorillas to install those fill plugs...they are always super tight when it's the first time of servicing.

    Note: I've never seen a drain plug with no magnet on it but mine didn't have one. I'll probably buy a replacement with a magnet for next service.

    Replace the crush washers and I think the torque spec is 29-37 ft/lbs but I just give it a good snug pull and watch the washer get crushed. Fill with the WS until it overflows. (Be careful to ensure you get over a qt in there...you can get a false reading with it coming out since there's not a lot of room and the air can push fluid out.) I move the hose around a bit when it's almost full to ensure I get it full.

    Note: I did it at 25,000 miles but, from now on, will go 50,000 miles...the TS oil that came out was very, very new looking...which is good.
     
  2. ColoradoCrow

    ColoradoCrow Active Member

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    Nice work. I can imaging the strain on the gearset in a prius is minor compared to say a large SUV...When I did the transaxle service on my 2002 Rover the front was dirty but thick...rear was like black water....:mad: I'm sure it was never done. So beacuse of that I redid ALL the fluids..so I know when it was done last. I'm positive that towing and off roading puts a toll on transaxles more. I know a guy who rebuilts the snowcats EVERY summer for Copper and Breckenridge ski resorts. Huge gears with low ratios..he tells me the gear oil doesn't last long.
     
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  3. bisco

    bisco cookie crumbler

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    is this another one of toyotas 'lifetime fluids'?
     
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  4. Mendel Leisk

    Mendel Leisk Senior Member

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    Apparently, unless you drive special conditions, and same story for transaxle fluid:

    upload_2023-5-28_13-27-13.png
    (every 60K miles or 6 years)

    I think if you just ignore the "special operating conditions", do it anyway, you can't go far wrong. The follow is at every 5K miles interval, seems a little nuts:

    upload_2023-5-28_13-29-25.png
     
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  5. ColoradoBoo

    ColoradoBoo Senior Member

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    Good question...so I pulled out my unused (worthless) Warranty and Maintenance guide from the glove box and had to search for a bit...it does say, at 60,000 or 5 years to replace if tow or hauling stuff and never in the regular section.

    One funny thing in there a lot is "Re-torque drift shaft nut (AWD)" and not a single Toyota tech/mechanic I've asked said they've ever found one lose...not even The Car Care Nut on YouTube. (I asked him when he used to do live Q&A sessions.) But, yeah, it says to go ahead an wait 10,000 between oil changes...nope.
     
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  6. Mendel Leisk

    Mendel Leisk Senior Member

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    No kidding; the event-by-event format is hopeless, compared to a simple (and very compact) table format, say with miles/months columns and the various service rows.

    the sand pounder: that’s almost certainly how the schedule is first laid out.

    I’ve translated the 4th gen US sched to table format, but just the regular (not special conditions, and IIRC I did it before advent of AWD. See attached:
     

    Attached Files:

    #6 Mendel Leisk, May 29, 2023
    Last edited: May 29, 2023
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  7. Hamza Masarwa

    Hamza Masarwa Junior Member

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    Hello
    I need the manual that contain this information for prius 2016 plz!

    Posted via the PriusChat mobile app.
     
  8. Mendel Leisk

    Mendel Leisk Senior Member

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    There’s at least two places you can download pdf owners manuals. One is the US site Toyota Tech Info (just Google that). Click on the “manuals” tab there, fill in your car info and it’ll show all available manuals.
     
  9. ColoradoBoo

    ColoradoBoo Senior Member

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    Wow does it really say 144 months (12-years) before changing spark plugs? Nope. 100,000 miles or 10-years is a good rule...even when you have a pretty big job of removing a ton of stuff (wipers, plastic and metal cowls, exhaust manifold, etc.) to get to the 3 back plugs in the V-6's. For the 4-cylinders, it's usually a 30-minute job even when you have to remove parts of the wiring harness on the old 4-cylinders to get access to the coils. For me, the scariest part is those crappy plastic clips (ignition coil connector)...SO easy to break the tabs so I keep a stash of spares for that reason...they are not hard to replace when you know how.
    My 2014 Tundra hits 10 next summer so I'm already planning on a 100% inspection and, probably, replacing, a bunch of stuff....belts, plugs, hoses, caps (radiator and fuel), etc. With OEM stuff, of course.