8 speed

  1. Welcome to GM Inside News Forum – General discussion forum for GM

    Welcome to GM Inside News Forum - a website dedicated to all things GM.

    You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, Join GM Inside News Forum today!
     
Results 1 to 4 of 4

Thread: 8 speed

  1. #1
    Walking
    Join Date
    Apr 2014
    Location
    Georgia
    Posts
    2
    Thanks
    0
    Thanked 2 Times in 1 Post
    My Ride
    Sierra Denalli/2014/Sonoma Red

    8 speed

    How is your 8 speed transmission, mine has issues that dealer cant fix

  2. Remove Advertisements
    GM Inside News
    Advertisements
     

  3. #2
    4.6 Liter Northstar V8 rockyspaw's Avatar
    Join Date
    Oct 2007
    Location
    in the Buff
    Posts
    1,879
    Thanks
    1,858
    Thanked 1,032 Times in 525 Posts
    My Ride
    09 G6 GXP 05 Rainier 81 Vette

    Re: 8 speed

    According to TSB (Technical Service Bulletin) 18-NA-355, the latest update addresses “torque converter clutch (TCC) shudder conditions on 8L45 and 8L90” eight-speed automatic transmissions, RPO codes M5N, M5T, M5U, and M5X. Affected vehicles include Chevrolet, GMC and Cadillac vehicles.

    As of July 8th, 2019, GM began using a new type of Mobil 1 automatic transmission fluid for the troublesome transmissions. Customers that complain of shuddering and harsh shifting characteristics in the 8-speed GM transmissions are recommended for a trans fluid flush. As of August 7th, GM dealers should also be flushing all potentially affected new vehicles on the lot.
    I wish they all could be California squirrels!
    Past Rides: 2003 Grand Am GT1 (saved me), 1995 Bonneville SLE (RIP), 1986 635 CSi, 1984 Estate Wagon, 1978 Malibu Classic, 1978 Corvette, 1975 Vega Kammback (Miss ya'), 1971 Dodge Dart Swinger (STFU...it got me there!)

    "Nothing happens until something happens then everything happens!"

  4. The Following User Says Thank You to rockyspaw For This Useful Post:

    TruckMan (06-23-2020)

  5. #3
    6.2 Liter LS9 Supercharged V8 TruckMan's Avatar
    Join Date
    Sep 2007
    Location
    Fort Worth, TX
    Posts
    6,287
    Thanks
    4,566
    Thanked 2,687 Times in 1,300 Posts
    My Ride
    2015 Sierra Denali 6.2L

    Re: 8 speed

    Mine had the shudder and a torque converter replacement a while back. No problems since. Glad I have the 100k mile warranty. I'm at about 65k.
    GMI Site Rules: 11. "Trolling", or making posts with the sole intention of creating problems on the forums is obviously against the forum guidelines. We define trolling as a member that appears to have the sole purpose of posting just to spite the majority of the site or cause flame wars in threads they participate in. PLEASE respect differing opinions on the site at all times!

  6. Remove Advertisements
    GM Inside News
    Advertisements
     

  7. #4
    4.6 Liter Northstar V8
    Join Date
    Jul 2011
    Location
    New York
    Posts
    1,579
    Thanks
    89
    Thanked 946 Times in 521 Posts
    My Ride
    2001 Trans Am Black

    Re: 8 speed

    I have the 45 in the Colorado and through 5k miles so far no issues, every once in a while I can feel a bit of a jerk in the 2-1 downshift coming to a stop, but no shuddering issues.

    Regarding rockys post above, that's interesting, I presume that's for the full sizers. On the Colorado/Canyon forums, March '19 was stated to be the factory switchover date for the M1 tans fluid. I also read that dealers were supposed to flush any trucks in stock at that time. Now, my truck was a 1/19 build although I bought it in November. So I'm not sure which fluid it has. I'd like to believe the dealer followed GM's direction to flush it, but I never hold a lot of faith in dealers.
    2001 Pontiac Trans Am
    2016 Chevy SS Sedan
    2017 Chevy Traverse
    2019 Chevy Colorado

    Past:
    2016 Chevy Traverse
    2012 Buick Regal GS
    2010 Chevy Traverse
    2003 Cadillac Seville SLS
    2003 Chevy Blazer M5
    1989 Pontiac Firebird

  8. Remove Advertisements
    GM Inside News
    Advertisements
     

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Powered by vBadvanced CMPS v4.1.2