Forum Discussion

Ed_Manifold's avatar
Ed_Manifold
Explorer
Jul 10, 2020

Synthetic Trans Fluid

I had Transynd synthetic oil installed in my 3000 Allison transmission at 34,911 miles on 2/12/15. My understanding was with the synthetic oil installed that I would not need to service again until approx. 100,000 miles. The mechanic that is now doing some of my service work told me that I still needed to service the transmission yearly. I now have 47,407 miles. I am concerned that I have not been servicing my transmission correctly. Please help me understand what the correct service requirements are?
Class A
  • lryrob9301's avatar
    lryrob9301
    Explorer
    Jul 10, 2020
    You need to find a different mechanic, he is taking you to the cleaners over recommending unneeded services. With Transynd, your transmission is good for 150,000 miles or 6000 hours of operation or 48 months whichever comes first. The filters need to be changed 75,000 miles or 3000 hours of operation or 36 months whichever comes first. This is as per the Allison service manual.
  • time2roll's avatar
    time2roll
    Nomad
    Jul 10, 2020
    I go with miles only. But then I don't have an allison. Consider going 18 to 24 months. As much as they would have you believe it there is no one year expiration on the fluid. JMHO
  • wolfe10's avatar
    wolfe10
    Explorer
    Jul 10, 2020
    theoldwizard1 wrote:
    gbopp wrote:
    Change your transmission fluid on a regular basis. It's cheap insurance.

    Concur !

    I usually also tell people to use the OEM recommended fluid.


    So, you are recommending going from Allison's Transynd BACK to Dexron???

    Transynd did become the OE fluid shortly after 2002.
  • theoldwizard1's avatar
    theoldwizard1
    Explorer II
    Jul 10, 2020
    gbopp wrote:
    Change your transmission fluid on a regular basis. It's cheap insurance.

    Concur !

    I usually also tell people to use the OEM recommended fluid.
  • wolfe10's avatar
    wolfe10
    Explorer
    Jul 10, 2020
    Suspect somewhere between every year and every 10+ years (based on your miles/yr) is the correct answer.

    Were it me, a fluid and filters change every 5 years with your few miles per year should be fine as long as not other issues (like coolant in fluid, fluid discoloration, etc).
  • gbopp's avatar
    gbopp
    Explorer
    Jul 10, 2020
    Change your transmission fluid on a regular basis. It's cheap insurance.
  • jdc1's avatar
    jdc1
    Explorer II
    Jul 10, 2020
    Tiny particles can clog the valves. The filter cannot catch it all. While synthetic fluid can withstand higher temperatures, it cannot do anything different when it comes to these particles.
  • Lwiddis's avatar
    Lwiddis
    Explorer II
    Jul 10, 2020
    What does the manufacturer, Allison, recommend?
    Why wouldn’t you follow Allison’s advice?

About Motorhome Group

38,711 PostsLatest Activity: Mar 25, 2025