PTU / RDU Fluid Change

Discussion in 'Generation 4 - Maintenance & Troubleshooting' started by Joshw0000, Feb 19, 2020.

  1. Joshw0000

    Joshw0000 SHO Member

    Joined:
    Sep 20, 2018
    Messages:
    237
    Likes Received:
    135
    Gender:
    Male
    Location:
    North Carolina
    Hey guys, I've been lurking the forums lately and came across some posts about changing the PTU fluid. I have a '12 non PP SHO so I'm sure there's no drain plug. My car has nearly 80K miles and there's no telling if the previous owner ever changed it. I sure haven't in the nearly 20K miles I've owned it. I don't abuse my car or take it to the track but I'm also never second off the line at a green light.

    So I ordered a quart of Royal Purple 75w140, some thread sealant, and a cheap pump for reinstalling the fluid. I think the pump I have at home will work for sucking out the old fluid, but if not what better time to tell the wife I need a new tool?

    So now, the dumb question... What about the RDU? Everyone seems concerned about the PTU but not a lot of talk about changing the RDU fluid. If anyone can point me to some info about changing that fluid, I'd appreciate it.

    Sent from my SM-N960U using Tapatalk
     
  2. FiveLeeter918

    FiveLeeter918 Ortiz Performance Sales Supporting Member

    Joined:
    May 22, 2017
    Messages:
    631
    Likes Received:
    679
    Gender:
    Male
    Occupation:
    Mechanical Engineer
    Location:
    Tulsa, OK
    Home Page:
    3/8" ratchet to remove fill plug, suck out old fluid and refill with good 80w90 diff fluid. You can pull the cover but it's more work for not much gain.

    Prepare to be stinky for a few days...
     
    Joshw0000 likes this.
  3. FiveLeeter918

    FiveLeeter918 Ortiz Performance Sales Supporting Member

    Joined:
    May 22, 2017
    Messages:
    631
    Likes Received:
    679
    Gender:
    Male
    Occupation:
    Mechanical Engineer
    Location:
    Tulsa, OK
    Home Page:
    takes 2.4 pints (38.4 fluid ounces) of fluid, a little over a quart.
     
    Joshw0000 likes this.
  4. b4black

    b4black SHO Member

    Joined:
    Dec 7, 2012
    Messages:
    152
    Likes Received:
    119
    Location:
    IL
    Don't be surprised if you only can get out about 8 oz. That's what many report. Suck out what you can and top it back off.
     
  5. Joshw0000

    Joshw0000 SHO Member

    Joined:
    Sep 20, 2018
    Messages:
    237
    Likes Received:
    135
    Gender:
    Male
    Location:
    North Carolina
    Thanks guys. Anyone have a picture of the RDU plug? Or general location? I'm pretty sure I can find the PTU.

    No idea how long this is gonna take me but I'm planning to tackle it this weekend.

    Sent from my SM-N960U using Tapatalk
     
  6. FiveLeeter918

    FiveLeeter918 Ortiz Performance Sales Supporting Member

    Joined:
    May 22, 2017
    Messages:
    631
    Likes Received:
    679
    Gender:
    Male
    Occupation:
    Mechanical Engineer
    Location:
    Tulsa, OK
    Home Page:
    No pic, but it's on the diff itself and looks like a 3/8" ratchet fitting
     
    802SHO and Joshw0000 like this.
  7. luigisho

    luigisho SHO Member

    Joined:
    Nov 2, 2001
    Messages:
    9,464
    Likes Received:
    2,296
    Location:
    va beach,va
    Home Page:
  8. Joshw0000

    Joshw0000 SHO Member

    Joined:
    Sep 20, 2018
    Messages:
    237
    Likes Received:
    135
    Gender:
    Male
    Location:
    North Carolina
    Much appreciated!

    Sent from my SM-N960U using Tapatalk
     
  9. Johnbigdog

    Johnbigdog SHO Member

    Joined:
    Feb 17, 2017
    Messages:
    1,159
    Likes Received:
    1,408
    Gender:
    Male
    Location:
    michigain
    The vent should be al 11 mm. You can remove it and clean it out and reinstall it. The cap may rattle but if you blow/suck through it it may be restricted. A little brake clean may go a long way.
     
    SHOdded and Joshw0000 like this.
  10. Joshw0000

    Joshw0000 SHO Member

    Joined:
    Sep 20, 2018
    Messages:
    237
    Likes Received:
    135
    Gender:
    Male
    Location:
    North Carolina
    This ain't cutting it. Time to go buy a real fluid extractor. [​IMG]

    Sent from my SM-N960U using Tapatalk
     
    luigisho likes this.
  11. Joshw0000

    Joshw0000 SHO Member

    Joined:
    Sep 20, 2018
    Messages:
    237
    Likes Received:
    135
    Gender:
    Male
    Location:
    North Carolina
    Welp the deed is done. If I can do it anyone can!

    That RDU was a pain. The bracket that holds nothing makes it impossible to get the plug in and out. I ended up getting about a pint in the RDU and maybe 1/2 pint in the PTU.

    Sent from my SM-N960U using Tapatalk
     
    citysmoke likes this.
  12. b4black

    b4black SHO Member

    Joined:
    Dec 7, 2012
    Messages:
    152
    Likes Received:
    119
    Location:
    IL
    802SHO and SHOdded like this.
  13. Tbird6

    Tbird6 New Member

    Joined:
    Dec 24, 2015
    Messages:
    19
    Likes Received:
    14
    Gender:
    Male
    Yes I struggled with that crappy Harbor Freight vacuum pump for a long time too!
    Finally had enough and started researching fluid extractors and am very glad I did!

    Ended up with a EWK Pneumatic/Manual 6.5L model with the added brake fluid hose and fitting. A bit more than I wanted to spend at about $90 with all the adapters but for my 2013 MKS EcoBoost it's a big time saver. You can find them on EBay and Amazon.
    Another tool that until you get one you don't think you will use it. It's more than paid for itself in the year I have owned it

    A couple of things to think about? This unit uses a down push to generate the vacuum. Sounds like a small thing but it's not. That pump you have takes 2 hands at least to operate and the hoses are all curled up too. It's a nightmare for one guy to use. The down push allows you to work against the ground so it's real easy. Another key feature is it can also be compressed air powered so you don't have to push a thing.

    I find that pulling a vacuum works best if you can walk away and do something else why the fluid is being pulled out.

    Fluid Extractor.jpg
    .
    .
    .
     
    SHOdded, 15SHOPP and luigisho like this.
  14. Joshw0000

    Joshw0000 SHO Member

    Joined:
    Sep 20, 2018
    Messages:
    237
    Likes Received:
    135
    Gender:
    Male
    Location:
    North Carolina
    That looks almost exactly like what I bought. Except I went to Harbor Freight because it was close and I needed it quick. It was $90 before the 20% discount so about $75.

    https://www.harborfreight.com/23-gallon-Manual-Fluid-Extractor-62643.html

    It was much easier than what I started with.

    I also ended up going back after the fact and buying some longer socket extensions for removing the PTU cap and a low profile socket for removing the RDU cap. Next time will be much easier.

    EDIT - Just realized yours can be hooked to a compressor. That's definitely better. I may end up mounting a fitting to mine. It was still a pain to crawl out from under the car to give it a few pumps every so often.

    Sent from my SM-N960U using Tapatalk
     
    Last edited: Feb 26, 2020
    SHOdded likes this.
  15. Joshw0000

    Joshw0000 SHO Member

    Joined:
    Sep 20, 2018
    Messages:
    237
    Likes Received:
    135
    Gender:
    Male
    Location:
    North Carolina
    This is how I removed the PTU cap the first time. It wasn't easy fishing it through by myself. Next time I'll only have to connect 2 or 3 extensions and shouldn't have to start at 1/2" and scale down to 3/8". [​IMG]

    Sent from my SM-N960U using Tapatalk
     
    SHOdded likes this.
  16. Tbird6

    Tbird6 New Member

    Joined:
    Dec 24, 2015
    Messages:
    19
    Likes Received:
    14
    Gender:
    Male
    Yes the compressed air was a plus for me too. I almost got the Harbor Freight one. They are about the same really.
    .
    .
    .
     
  17. Wsho

    Wsho SHO Member Supporting Member

    Joined:
    Nov 26, 2017
    Messages:
    304
    Likes Received:
    427
    Gender:
    Male
    Occupation:
    Flowmaster/ Holley performance
    Location:
    Sacramento California
    I was thinking of getting AMSOIL 75W-140 for the PTU
    And 75W-90 for RDU
    Or is Royal Purple better?
     
    SHOdded likes this.
  18. bpd1151

    bpd1151 Lurking Around

    Joined:
    Feb 21, 2010
    Messages:
    2,108
    Likes Received:
    4,186
    Gender:
    Male
    Occupation:
    LEO 23+yrs
    Location:
    SHOcago 'Burbs
    I've heard good things about Amsoil, but I myself have consistently used the RP Max Gear products, and never had a failure of either of those components alone.

    I'd say you be good rolling with either/or.

    Sent from my SM-N950U using Tapatalk
     
    Last edited: Feb 27, 2020
    SHOdded likes this.
  19. SM105K

    SM105K HATER MAKER

    Joined:
    May 3, 2018
    Messages:
    3,037
    Likes Received:
    3,126
    Gender:
    Male
    Occupation:
    Paper Slayer
    Location:
    Arizona
    Redline Lightweight Shockproof is where it is at.
     
    shoblock likes this.
  20. Wsho

    Wsho SHO Member Supporting Member

    Joined:
    Nov 26, 2017
    Messages:
    304
    Likes Received:
    427
    Gender:
    Male
    Occupation:
    Flowmaster/ Holley performance
    Location:
    Sacramento California
    Here's an independent test that some guy did between royal purple and AMSoil . Need to check this out pretty cool

     

Share This Page

If you wish to help keep SHOforum running, please click the donation button below