Jump to content
  • Sign up for FREE! Become a GM-Trucks.com Member Today!

    In 20 seconds you can become part of the worlds largest and oldest community discussing General Motors, Chevrolet and GMC branded pickups, crossovers, and SUVs. From buying research to owner support, join 1.5 MILLION GM Truck Enthusiasts every month who use GM-Trucks.com as a daily part of their ownership experience. 

Should I disable DFM?

Recommended Posts

I have a 2019 RST with the L84 V8 8 speed with about 75k miles. No issues, other then the transmission being a bit rough. A transmission fluid flush helped with that, though now I feel more of a vibration when DFM kicks in than I remember.  Is it worth disabling the DFM to help prevent lifter failure? Or am I overthinking that?  Harder to find information on failures for this engine before the 2021 model failure.



Link to comment
Share on other sites

I would disable the DFM because the engine runs smoother, not because of lifter failure. There are many opinions or different trains of thought on lifter failure. I believe that disabling DFM reduces the occurrence of lifter failure but there is no scientific proof from anyone (including General Motors) that this is true. GM spent millions of dollars developing and testing DFM (under heavy Federal Government pressure) so they will not tell you DFM can cause lifter failure. This is only my opinion but I would definitely disable the DFM.

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

By using this site, you agree to our Terms of Use.