Jump to content

6L80e to 4L60e

xKingdom
 Share

Recommended Posts

xKingdom Enthusiast

xKingdom

Posted
Posted

Hello everyone, I have a 2008 and 2009 Avalanche LTs. (I know it’s not a Silverado but I really need some help here) my main issue is my 2008 has a built 5.3 and a built 4l60e. My 2009 is rust free and I’m currently installing my 9 inch lift on it. The only issue is the 6 speed transmission is junk, it has no gears besides park. Is it possible to swap the 2008 motor and 4L60e into my 2009? I’m hoping it’s going to be as simple as a normal motor swap but I’m not sure what all it entails. I’m sure the cluster is different but besides that can I just transfer my ECM and tcm over? Or will I need to do some programming to my bcm and such. Thank you in advance!

davester Senior Enthusiast

davester

Posted
Posted

Motor will be straightforward, the transmission won't be, because there are a bunch of other stuff that need to be changed, like the steering column and instrument panel.  The IP in particular probably will be a problem to get working right.  And with gmt900's, it's not just swapping computers like you could with gmt800's, a lot more stuff is vin-locked, and there can be more variations in other parts, such as abs controllers for example.

  • Like 1
CamGTP Senior Enthusiast

CamGTP

Posted
Posted

The 6 speedo is a far better transmission than the 4L60e when it comes to lifts and big tires too.

 

The long gear changes of the 4 speed will suck and you need less rear gear with a 6 speed because of the mechanical advantage the 2 extra gears give you.

  • Like 1
xKingdom Enthusiast

xKingdom

Posted
  • Author
Posted
44 minutes ago, CamGTP said:

The 6 speedo is a far better transmission than the 4L60e when it comes to lifts and big tires too.

 

The long gear changes of the 4 speed will suck and you need less rear gear with a 6 speed because of the mechanical advantage the 2 extra gears give you.

So your thinking I should have the 6 speed rebuilt and call it good?

  • Like 2
xKingdom Enthusiast

xKingdom

Posted
  • Author
Posted
5 hours ago, davester said:

Yes, that would definitely be the way to go, IMHO.

I called a few transmission shops and none of them really wanted to work on 6L80s, that’s why I wanted to swap my 4l60 in

xKingdom Enthusiast

xKingdom

Posted
  • Author
Posted
On 3/4/2025 at 9:47 PM, davester said:

That's nuts.  Do they just not work on vehicles newer than 10 years old?j

Well from the 5 shops I’ve called in my area (100 mile radius from my house) all of them told me the 6l80 is junk and to just keep my 4 speed. My 4 speed was rebuilt buy my local motorsports shop and they didn’t really want to do it but they threw all billet parts in that’s why I didn’t want to keep the 6l80

CamGTP Senior Enthusiast

CamGTP

Posted
Posted

The 6L80 is a far better transmission, those transmission shops just don't like doing the work. The only downfall of the transmission is the stock torque converter, once that is replaced, they are really good transmissions.

 

I also don't really trust those shops if the first thing out of their mouth is that the 6L80e is junk, why would they not want to take someones money for a rebuild that they can do. That just tells me they are lazy and not worth my time if they don't want to fix the thing that needs repairs.

 

At this point I'd be ordering a transmission online from someone, lots of places do it. Then all you'd need is the transmission programmed after you install it.

  • Like 1
xKingdom Enthusiast

xKingdom

Posted
  • Author
Posted
2 hours ago, CamGTP said:

The 6L80 is a far better transmission, those transmission shops just don't like doing the work. The only downfall of the transmission is the stock torque converter, once that is replaced, they are really good transmissions.

 

I also don't really trust those shops if the first thing out of their mouth is that the 6L80e is junk, why would they not want to take someones money for a rebuild that they can do. That just tells me they are lazy and not worth my time if they don't want to fix the thing that needs repairs.

 

At this point I'd be ordering a transmission online from someone, lots of places do it. Then all you'd need is the transmission programmed after you install it.

I was thinking of buying one from oreillys. Like I said though would it be a simple swap to just put my motor and trans out of my 08 truck into the 09? I could definitely keep all the 6l80 parts but I’d really like to utilize my built 4l60 since I already spent the money to have it all gone through.

CamGTP Senior Enthusiast

CamGTP

Posted
Posted

The engine transmission swap is simple but that's it.

 

The wiring and programming is your problem. Different wiring harness, different fuse blocks. The 4L60e is a external TCM the 6L80e is an internal TCM. The other modules on the CAN-BUS are technically programmed to match everything with a 2009 truck with a 6 speedo auto. So things like ABS and all that other stuff may not work again because of the calibration mismatch going on.

  • Like 1
xKingdom Enthusiast

xKingdom

Posted
  • Author
Posted
3 hours ago, CamGTP said:

The engine transmission swap is simple but that's it.

 

The wiring and programming is your problem. Different wiring harness, different fuse blocks. The 4L60e is a external TCM the 6L80e is an internal TCM. The other modules on the CAN-BUS are technically programmed to match everything with a 2009 truck with a 6 speedo auto. So things like ABS and all that other stuff may not work again because of the calibration mismatch going on.

I’ll try to call my local dealership and see what they can do for me. If they can’t do anything I’ll cave and pick up a 6 speed, the nice part is I have a whole donor truck so it’s not like I’ll have to pick up many parts in terms of any wiring harnesses

newdude Senior Enthusiast

newdude

Posted
Posted

You'd be much better off rebuilding the 6L80 or buying a rebuilt upgraded one.  

 

4L60 is ran off an external TCM, 6L80 is an internal TCM so the truck would be wired differently between the two and would require some big efforts to swap it to the 4L.  

 

  • Like 1
swathdiver Senior Enthusiast

swathdiver

Posted
Posted

In order to downgrade your truck to a 4L60 you would have to swap in new wiring harnesses and multiple programming operations and a new cluster, shifter, cross member, etc.  

 

Less expensive and aggravating to just overhaul the 6L80.

swathdiver Senior Enthusiast

swathdiver

Posted
Posted
On 3/4/2025 at 5:16 AM, davester said:

Yes, that would definitely be the way to go, IMHO.

 

Seems like we're getting this question every week now Dave!

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • Aimatdeer
      Ac not keeping up

      By Aimatdeer · Posted

      Monday looks like a good day for the dealer to test an ac issue. Hopefully it all turns out good.
    • CamGTP
      Gas Prices

      By CamGTP · Posted

      Paid $2.72 for E85 today.
    • Atlas
      Gas Prices

      By Atlas · Posted

      Welcome back! No, it definitely doesn't pass the sniff test. Even "ceasefire" needs an alternative definition these days.    $5.29 at Kroger today
    • bluev8
      Intermittent no-code issues on 2022.5+ V8 trucks — what did the shop fail to capture?

      By bluev8 · Posted

      That makes sense, and I think you are describing the real product problem. Capturing data is the easy part. If the owner or technician has to manually dig through five minutes of millisecond-level logs, the product has already failed. The device would be at the ECM harness, not at the OBD port, so I agree that data retrieval and event marking need to be thought through carefully. The way I am thinking about the architecture is: The recorder itself should not depend on a phone, app, Bluetooth, Wi-Fi, or cloud connection to capture the event. It should always keep a local rolling buffer and lock the event locally. A button, phone app, or small cabin device would only act as an event marker. If the driver feels a stumble and presses the button 10–30 seconds later, the pre-buffer has to already contain the useful data. For data retrieval, the practical options would be a sealed service USB lead, Wi-Fi download, or a phone/cabin companion device. I would not expect the owner to remove the ECM-side module or work with raw files directly. The cloud or AI side would be for interpretation, not for capturing the event. The truck may have no connection when the issue happens, so the evidence has to be saved locally first. After that, cloud processing could help decode the data, compare it against baselines, and generate a readable report. For the first version, I would keep the automatic triggers conservative and objective: driver event marker bus-off error passive voltage drop / brownout device reset FIFO or queue overflow a normally periodic message disappearing side-to-side communication mismatch, if the topology supports that For “learning normal,” I agree with your point, but I would not want to overclaim it as automatic root-cause diagnosis at first. A realistic first step would be learned baseline comparison for that specific vehicle and operating condition. For example, a value would only be compared against similar conditions: RPM range load / MAP throttle position gear / vehicle speed coolant and oil temperature battery voltage AFM/DFM state, if decoded and validated Then the report could flag things like: this periodic message disappeared compared with its normal timing this value deviated from this vehicle’s normal range under similar conditions the same abnormal pattern repeated after the same type of event the anomaly occurred together with voltage, oil-pressure, misfire, or communication changes But I would still call that “abnormal pattern detected,” not “replace this part,” unless there is enough validated repair data behind it. So the intended product would not be “here is a huge log.” It would need to be an event package: what triggered the capture how much pre/post data was preserved what changed before and after the event whether the device itself reset, overflowed, or saw a bus error selected graphs around the event raw data only as supporting evidence From your perspective, what would make this kind of report useful instead of just another datalog? For example: What are the top 5 parameters or events you would want highlighted first? Would you trust a learned baseline for that specific vehicle, or would you prefer fixed thresholds? How much false-positive flagging would be acceptable before you stopped looking at the reports? What would a one-page report need to show for an independent shop to take it seriously? For misfire, AFM/DFM, oil pressure, or U-code complaints, what would you want the tool to flag automatically?
    • scotthvac.net
      2022-24 halogen - led grille swap

      By scotthvac.net · Posted

      2024 Silverado 2500 HD LTZ grille no camera Parts list   84603331 84913656 84913657 84913654 84913655 84911567 84911568 85646092 85646093 85797921 85797922   11570637  x10-15   grille/bumper bolts 11546500  x10      grille clips 11571006  x10      push/retainer clips 11546454  x6       nut retainers 11611609  x6       M5 bolts 11610700  x6       molding/trim retainers

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...