Jump to content

Harsh Shifting on the 8L90 Automatic Transmission

Retired Bob

By Retired Bob
in Troubleshooting & Recalls

Recommended Posts

Retired Bob Enthusiast

Retired Bob

Posted
Posted

TechLink article:

http://sandyblogs.com/techlink/?p=7170

 

There may be several harsh shifting conditions on some 2015-2016 Silverado, Sierra, Yukon and Escalade models equipped with the 5.3L engine (RPO L83) or 6.2L engine (RPO L86) and the 8L90 automatic transmission (RPOs M5U, M5X). The shift conditions may include:

• Harsh 1-2 upshift (except for the first 1-2 upshift of the day)
• Harsh 3-1 downshift when de-accelerating to a stop
• Harsh downshift under heavy throttle apply
• Active Fuel Management (AFM) V4 to V8 transition harshness (6.2L engine only)
• Coast-down downshifts (6.2L engine only)

 

  • Replies 33
  • Created
  • Last Reply
Skeeter McSkeet Senior Enthusiast

Skeeter McSkeet

Posted
Posted

Wonder why it would say 2015-2016 models, and have this "tip" below?

 

TIP: Due to the installation of the new TCM software, Bulletin #14-07-30-001 should not be used on 2015 model year vehicles. It will not allow for proper clutch learning.

 

 

Sent from my kayak

joshc64311 Enthusiast

joshc64311

Posted
Posted

Wonder why it would say 2015-2016 models, and have this "tip" below?

TIP: Due to the installation of the new TCM software, Bulletin #14-07-30-001 should not be used on 2015 model year vehicles. It will not allow for proper clutch learning.

Sent from my kayak

Goods question, is the 8l90 an 8 speed
Skeeter McSkeet Senior Enthusiast

Skeeter McSkeet

Posted
Posted

Did the 5.3l in 2015 come with the 8speed?

I'm not positive on that, mines a 6 and so is my friends 15, both 5.3. I want to say it wasn't an option, but I can't for sure lol.

 

 

Sent from my kayak

TJay74 Senior Enthusiast

TJay74

Posted
Posted

2015 6.2 was 8 speed, 5.3 was 6 speed. 2016 6.2 was 8 speed, 5.3 was 8 speed if it was a SLT/LTZ optioned truck.

nluchau Enthusiast

nluchau

Posted
Posted

TechLink article:

http://sandyblogs.com/techlink/?p=7170

 

There may be several harsh shifting conditions on some 2015-2016 Silverado, Sierra, Yukon and Escalade models equipped with the 5.3L engine (RPO L83) or 6.2L engine (RPO L86) and the 8L90 automatic transmission (RPOs M5U, M5X). The shift conditions may include:

• Harsh 1-2 upshift (except for the first 1-2 upshift of the day)

• Harsh 3-1 downshift when de-accelerating to a stop

• Harsh downshift under heavy throttle apply

• Active Fuel Management (AFM) V4 to V8 transition harshness (6.2L engine only)

• Coast-down downshifts (6.2L engine only)

 

I have a 2016 Silverado 5.3 6 speed z71 with a Harsh 3-2 downshift when de-accelerating to a stop. Am I candidate for this????

HondaHawkGT Senior Enthusiast

HondaHawkGT

Posted
Posted

I have a 2016 Silverado 5.3 6 speed z71 with a Harsh 3-2 downshift when de-accelerating to a stop. Am I candidate for this????

No that's for the 8-speed only.

Cottonwoodguy Enthusiast

Cottonwoodguy

Posted
Posted

So after 7 trips to the dealership about shifting issues and having GM send an engineer to asses the situation and having them all say it is "Normal" for my truck to shift like crap in the low gears there is a TSB for it. What kind of crap is that? GM flat out lies to me for 8 months about the problem?

inspectorudy Enthusiast

inspectorudy

Posted
Posted

I have a 2016 LT Silverado with the same issue of hard lousy shifts. The service manager took it for a spin and declared that it was "Normal". He said that this 6-spd tranny is a lousy shifter because of the mpg issue and they won't re-program it because it will lower GM's fleet mileage. I even bought one of the devices that eliminate the 4/8 cylinder shift and it didn't help at all. We ought to make them fix this lousy transmission. Anyone know how?

Dnt Senior Enthusiast

Dnt

Posted
Posted

Fixed with Hypertech 2.0 part 2000 with latest updates.

inspectorudy Enthusiast

inspectorudy

Posted
Posted

Fixed with Hypertech 2.0 part 2000 with latest updates

 

Can you tell us what this entails? Is it a GM part or an aftermarket part? Did your dealer find this info or did you bring it to him?

Thanks

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.5k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,965
    Total Members
    8,960
    Most Online
    DaleB
    Newest Member
    DaleB
    Joined

  • Who's Online   5 Members, 1 Anonymous, 1,530 Guests (See full list)

  • Latest Articles

  • Posts

    • DaleB
      No Software Updates - Old Build

      By DaleB · Posted

      Hi all - my current truck is a 2022.5 1500 High Country 3.0. I bought the truck used last year. After doing some digging, I noticed that my truck's software is stuck on the original build from 2022. I have no available software updates. I talked to my dealer about this and they recommended not trying to force an update since the 36,000 mile warranty is expired. This is a big bummer since there have been many major releases since that have fixed small issues and improved speed/usability.   For reference, the current software build number is: full_gminfo37_gb-user 10 W158E-W164.4.2-QIH22B-563.3 158 release-keys Has anyone had a similar experience? Should I just forget about it and move on, or try a different dealer?
    • B07
      Needing this part.

      By B07 · Posted

      Sure. Buy it for me 🤣
    • B07
      Needing this part.

      By B07 · Posted

      Using zip ties but 2-3 they snap due to sharp edges. Just using a shoestring. Last longer. 🤣
    • Atlas
      Wow I'm in a pickle. (Broke down truck) and a story.

      By Atlas · Posted

      I ordered the Snap On...waiting for it to come in later this week or early next week.   New front cover, new crank seal and new balancer are on. Water pump, pulley, fan, hoses, and plastics reinstalled. I can move forward knowing all my timing marks are dead on and the front engine is hopefully sealed better than it was. Take 2 with the water pump...trying high temp thread sealer on the lower bolts.   Rebuilt injector and new-new regulator is in, it looks like new. Top intake reassembled and all the bits are reconnected and snugged down.   Thinking about knock sensors again, I located both of mine and, there's your problem, Francis... The driver's side one is broke, plastic is bashed in, part of the wire is bare, and it appears to have been damaged like that for a long time. I saw the wire but didn't think anything of it. The knock sensor might not be my pulled timing issue, but it sure looks suspect. It must still be conducting, otherwise I'd expect a CEL. But perhaps with its sacred crystal inside exposed, jilted and dirty, maybe it's sending mixed signals. So I'm waiting for one of those and a new pigtail to come in. Pass side sensor looks good, except for the spark plug wire resting on it (!). The plug wires are healthy so it shouldn't be causing an issue, but I separated them and added zip ties to nearby looms to keep everything well apart.   So, I'm down to installing a knock sensor AND, oh, replacing the exhaust and cat. I actually think that's going to be fairly easy, it's all bolt-together, all new stuff from Walker is laid out on the shop floor ready to go. Hopefully have this thing on the road again for the weekend.   My luck? It will still be leaking oil, coolant, pulled timing, intermittent CEL for running rich, or it probably won't run at all -- because that's how this project has gone.   I've never worked on a vehicle so ...hurt? ...cursed? in my life. Everything has been effed with SO HARD, but I think...knock on wood...I've managed to undo all the backyard stuff and we're almost reset back to "just" an 80k mile, 30 year old Blazer.
    • PunchT37
      Would this CV Shaft be bad?

      By PunchT37 · Posted

      Yes. You need to check out that thing, and the hub further.

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...