6.6L Duramax Diesel & Allison Powertrain (L5P/MGM)

170 topics in this forum

1. 2020 Silverado 2500 DEF usage 1 2 3 4 5

   By gjohnston7, June 3, 2020
   • 74 replies
   • 54.7k views
   • 
   • Madams1970
   • July 20, 2023

3. 2024 Allison transmission vibrating

   By James Z, June 15, 2023
   • 2 replies
   • 2k views
   • 
   • James Z
   • June 16, 2023

4. 220 Amp Alternator Question - 2021 Silverado 2500HD Duramax 1 2

   By tortiseshell, April 1, 2022
   • 16 replies
   • 10.2k views
   • 
   • Terry OBrien
   • May 20, 2023

5. I try not to look at this section... 1 2

   By Jettech1, January 1, 2023
   • 17 replies
   • 5k views
   • 
   • kevin74
   • May 11, 2023

6. Duramax Newbie

   By waltman, May 11, 2023
   • 0 replies
   • 1.9k views
   • 
   • waltman
   • May 11, 2023

7. Ticking sound at idle

   By Bones454, July 4, 2020
   • 8 replies
   • 10.6k views
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   • Hunter_s
   • May 9, 2023

8. Something locked up causing me to skit to a halt.

   By Steve Macedo, April 15, 2023
   • 7 replies
   • 2.4k views
   • 
   • 4x4Hank
   • April 30, 2023

9. Transmission fluid and filter change, temperature to check fluid level??

   By XY74, December 22, 2022
   • 5 replies
   • 8.4k views
   • 
   • XY74
   • April 18, 2023

10. Fuel filter change with push-button start

    By Penndel Zeke, December 19, 2020
    • 7 replies
    • 33k views
    • 
    • redwngr
    • April 15, 2023

11. Humming noise when cold started??

    By 2023 problem, March 16, 2023
    • 6 replies
    • 4.4k views
    • 
    • redwngr
    • April 13, 2023

12. 2020 and up, dpf system recall 1 2 3 4

    By shadow gray 2020 hd, May 25, 2022
    • 46 replies
    • 27.1k views
    • 
    • XY74
    • March 31, 2023

13. Anyone buy the GMC "Prepaid Mainenance" plan?

    By blamkin86, February 21, 2023
    • 3 replies
    • 2.1k views
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    • gemarsh
    • February 23, 2023

14. Airlift options for DRW?

    By John FX, January 19, 2022
    • 4 replies
    • 2.1k views
    • 
    • Aojaguar
    • February 18, 2023

15. Winter guard

    By gemarsh, December 12, 2022
    • 7 replies
    • 3.1k views
    • 
    • TripDad
    • January 11, 2023

16. 2022 LP5 Loud Air Noise on Throttle and Bad Fuel Economy

    By aleeuw, January 3, 2023
    • 9 replies
    • 3.2k views
    • 
    • GMCustomerService
    • January 9, 2023

17. sultastic spring shackles

    By anthonybehnken, December 6, 2020   

    • Rear spring shackles
    • 8 replies
    • 3.7k views
    • 
    • asilverblazer
    • January 9, 2023

18. DEF Tank - Frozen

    By ArrowsmithPML, December 20, 2022
    • 14 replies
    • 5.5k views
    • 
    • ArrowsmithPML
    • December 22, 2022

19. Aux heater

    By gemarsh, December 22, 2022
    • 3 replies
    • 1.8k views
    • 
    • CamGTP
    • December 22, 2022

20. Chrome Wheels for 2020 Sierra HD

    By TFrankl, November 30, 2022
    • 1 reply
    • 1.2k views
    • 
    • Core-Lokt
    • December 2, 2022

21. 2020 2500HD AT4 - 17K miles - Allison leaked and -REBUILD- 1500m from home 1 2

    By Kaamacat, October 7, 2021
    • 16 replies
    • 4.5k views
    • 
    • 64BAwagon
    • November 7, 2022

22. Allison 10 speed failure on a 2020 GMC 3500 with 13,500 miles

    By Richard Helm, August 26, 2022
    • 3 replies
    • 2.9k views
    • 
    • Richard Helm
    • November 3, 2022

23. 2020 GMC AT4 Garbage Brakes! 1 2

    By SVAT4, September 28, 2020
    • 16 replies
    • 16.4k views
    • 
    • Will Fair
    • October 11, 2022

24. No key fob detected, no audio, column steering lock

    By Rob505, August 19, 2022
    • 7 replies
    • 1.2k views
    • 
    • GMCustomerService
    • September 2, 2022

25. 2020 3500 6.6 Duramax Fan stays on

    By jfatboy54, July 19, 2022
    • 2 replies
    • 4.3k views
    • 
    • redwngr
    • August 17, 2022

26. 2021 Transmission Shudder

    By Jacksfr, August 5, 2022
    • 2 replies
    • 3.4k views
    • 
    • GMCustomerService
    • August 5, 2022