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6L80e 6spd Conversion

Ryan212

Well-Known Member
Messages
144
Location
Orlando
The 4l60 uses a t42 tcm that is external to the transmission. The 6l80 uses a t43 transmission controller that is built into the Transmission and controls the valve body directly.

Gauges will depend on the ecm talking on vpw to Controll the gauges. My rig has a full power train swap but I have not yet tried to get the oem gauge cluster to work with the duramax yet. I believe it can be done but I may have to build a converter to convert the signals.

Ryan
 

adventr

Well-Known Member
Messages
500
Location
United States
Yeah, as posted above, 4L60e uses external TCM (located on firewall just above PCM) and 6L80e uses internal TCM. That's why the harness conversion setup is needed.


As for engine swaps, if your rig is an Alpha (5.3l), then switching over to another LS engine would be super easy... Alpha uses E67 PCM, which is capable of running just about any late model LS engine (just need to flash it for engine application). Gauges would still function the same.
 

4speedfunk

Well-Known Member
Messages
4,212
Location
Tardville
This is going behind a 5-cyl, right? Has any consideration been given to the final drive ratio? This motor can barely pull the .70 overdrive with the stock tranny. Dropping to .67 will probably result in lots of 5-6 hunting at highway speeds...especially with oversize tires.
 

ReconH3

Guardian Angel
Messages
2,288
Location
Raleigh, NC
This is all amazing stuff. Wish I had access to somebody with that knowledge to be able to swap my Alpha to a NV4500.

On a different note. While you're doing all these mods and adapters, how about making a slip yoke eliminator plate for the rear output? :D


"Ex Umbris Venimus"
 

Ryan212

Well-Known Member
Messages
144
Location
Orlando
The e67 can only run 58x ls motors so 2006+ corvette ls2 and ls3. 2007+ new body style 5.3 Silverado/Tahoe before they went to direct injection in 2014
 

amrg

Well-Known Member
Messages
2,317
Location
Qatar
This is going behind a 5-cyl, right? Has any consideration been given to the final drive ratio? This motor can barely pull the .70 overdrive with the stock tranny. Dropping to .67 will probably result in lots of 5-6 hunting at highway speeds...especially with oversize tires.
I believe the truck can be programmed to never shift out of 5th for most driving conditions. With the 0.85 ratio in 5th and 35s that would be better than the 4L60e in 4th (should drive like a stock truck on 32s in 4th gear)
 
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adventr

Well-Known Member
Messages
500
Location
United States
Just for clarity, my h3 is a v8 model. I'm not 100% sure what all will be required for the 5cly models, or if it is even possible.
This is mainly to document what all is being done to my h3.

If a new bellhousing for the 5cyl exists, then it could be physically mated up, but I'm not sure about the electronic side.
The only 5cyl h3 that I've ever looked at in person had a t42 TCM, so it may be the same as what I'm doing to mine.
 

Ryan212

Well-Known Member
Messages
144
Location
Orlando
The 08+ runs the T42 TCM, where the 06-07 uses a P12 PCM that controls the Engine and Trans. The P12 was never used by GM with a 6Lxx trans, so you would likely need to swap to a 2008+ E67 and harness to control the engine and then the trans separate. One thing to be aware of is the T43 changed in the end of 2009, so you need to use a file that matches the OS or compatible OS part numbers. Flashing a 2015 T43 with a 2008 file will result in issues in most cases.
 

adventr

Well-Known Member
Messages
500
Location
United States
Was wondering about flashing the T43. What issues commonly arise from that?
My plan was to have my GM buddy hook his GM tool (not sure what they're using these days) up to the trans before I install it, and have him flash it back to an older vehicle.

My plan B was to swap out the 2015 T43 with an older T43.
 

High Five H2

Well-Known Member
Messages
1,627
Location
West Texas
Yeah, as posted above, 4L60e uses external TCM (located on firewall just above PCM) and 6L80e uses internal TCM. That's why the harness conversion setup is needed.

As for engine swaps, if your rig is an Alpha (5.3l), then switching over to another LS engine would be super easy... Alpha uses E67 PCM, which is capable of running just about any late model LS engine (just need to flash it for engine application). Gauges would still function the same.

The 4l60 uses a t42 tcm that is external to the transmission. The 6l80 uses a t43 transmission controller that is built into the Transmission and controls the valve body directly.

ok, makes sense. it's great you're doing all this research. I think this is one of the few things that the H3 needs to be a really good rig, and i'll definitely put off doing the SAS and do this first.
 

Ryan212

Well-Known Member
Messages
144
Location
Orlando
the module is basically offline, the last few bytes that are flashed into the controller are done by the bootloader in the T43 (newer style) vs the older T43 that are done as part of the flash process. I would just try the file that is in the trans and see if it communicates with the E67. The 2010 camaro is one example that changed controllers mid 2010 model year with no ECM changes to support the new and older versions. The newer T43 are more adaptive.
 

High Five H2

Well-Known Member
Messages
1,627
Location
West Texas
so, the E67 ECU will control the T43, that's correct? everything I've read says that the 6L80 came with the E38 ECU (I think). that's why I'm worried about using a different ECU.
 

4speedfunk

Well-Known Member
Messages
4,212
Location
Tardville
Recon...Converting to a NV-4500 shouldn't be a huge deal. I don't personally know much about the swap but, I know several guys that run NV-4500s behind all sorts of motors....Cummins, Ford, GM, Dodge, Jeep, etc. so I'm pretty sure the bell housing exists. Its such a popular tranny that conversion bells are very common. As for the rest of it?...you would need a factory Hummer (Colorado) pedal-set, clutch master cylinder, and hydraulic lines. I think the flywheel, clutch, throw-out, and slave, could all be sourced from the aftermarket.

Not sure where the stick would come up inside the vehicle. Also not sure what you would do, if you wanted to retain the stock Hummer t-case. Easiest fix is to swap to a NP-205, passenger-drop. Of course you would loose the 4:1, traction control, and full-time street mode. I know a great t-case guy that can build you whatever you want...twin-stick conversions...creeper gearsets...etc. Gear or Chain driven.

If you wanted to keep the BW-3393/3394, then you would have the same issues this guy is having...some sort of custom 5-bolt tailshaft, and custom input shaft. Easier to just swap-in the 205...its way stronger, and you would get the 2WD mode all of us solid-axle guys want.
 
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BIGFRY77

Well-Known Member
Messages
67
Location
Wisconsin
I live in the Wisconsin driftless area so I'm always going up hills, and the tranny constantly shifts back and forth from OD to 3rd. Depending on the hill, I always just down shift out of OD till I crest the hill. My biggest question with this swap is will it also be constantly shifting back and forth between 6th-4th?

I had read that they did try to use Active Fuel Management in the Alphas but that the motor would not switch to 4cyl long enough to provide any benefit.

So will in reality, (well soon find out I hope) the 4L80e actually improve the drive-ability of the H3?
 

Ryan212

Well-Known Member
Messages
144
Location
Orlando
E67 came with a 6Lxx in the CTS-V and automatic ZR1. The trailblazer SS guys have been doing the 6Lxx swaps for a while and 2007-2009 TBSS run the E67 as well.

The base code of the E38 and E67 are very similar, the E67 has far more inputs and outputs. Many of the E67 only tables are in the E38 binary such as dual IAT sensors and supercharger control.

Ryan
 

adventr

Well-Known Member
Messages
500
Location
United States
I live in the Wisconsin driftless area so I'm always going up hills, and the tranny constantly shifts back and forth from OD to 3rd. Depending on the hill, I always just down shift out of OD till I crest the hill. My biggest question with this swap is will it also be constantly shifting back and forth between 6th-4th?

I had read that they did try to use Active Fuel Management in the Alphas but that the motor would not switch to 4cyl long enough to provide any benefit.

So will in reality, (well soon find out I hope) the 4L80e actually improve the drive-ability of the H3?


I'm expecting a nice difference to be made in the drive-ability with the 6L80e. Much closer gear ratios, so it will be able to keep the engine in the "powerband". That's actually the main reason I'm doing the swap, rather than just dropping $1850 for a new 4l60e from GM.
Side benefits will include lower 1st and reverse gears, double overdrive, and an overall stronger transmission. Will be better suited to adding power adders later on.

Trans tuning will still be done through HP Tuners, so if there is something about it that you don't like (say shifting out of OD too easily), then that can be changed. I spent a considerable amount of time tuning my 4l60e to my liking. My final tune included torque converter clutch lockup in 2nd gear, which was never standard on factory programming, but really made a nice difference to me. Lots of slow winding hills around here, so 2nd gear locked up is quite useful and doesn't heat the trans up.
But that's all personal preference. I expect to do the same amount of tuning on the 6l80e as well.
 

adventr

Well-Known Member
Messages
500
Location
United States
the module is basically offline, the last few bytes that are flashed into the controller are done by the bootloader in the T43 (newer style) vs the older T43 that are done as part of the flash process. I would just try the file that is in the trans and see if it communicates with the E67. The 2010 camaro is one example that changed controllers mid 2010 model year with no ECM changes to support the new and older versions. The newer T43 are more adaptive.



Sounds like you've messed with this stuff before. :thumbs:

I think I will actually just try and use the trans as it sits. Hopefully it will communicate with my PCM!
My other option would be to buy a new T43 if this one isn't able to be flashed back to '09 specs?
 

06 H3

a.k.a. "The Jackal"
Messages
9,350
Location
Meridian, ID
Recon...Converting to a NV-4500 shouldn't be a huge deal. I don't personally know much about the swap but, I know several guys that run NV-4500s behind all sorts of motors....Cummins, Ford, GM, Dodge, Jeep, etc. so I'm pretty sure the bell housing exists. Its such a popular tranny that conversion bells are very common. As for the rest of it?...you would need a factory Hummer (Colorado) pedal-set, clutch master cylinder, and hydraulic lines. I think the flywheel, clutch, throw-out, and slave, could all be sourced from the aftermarket.

Not sure where the stick would come up inside the vehicle. Also not sure what you would do, if you wanted to retain the stock Hummer t-case. Easiest fix is to swap to a NP-205, passenger-drop. Of course you would loose the 4:1, traction control, and full-time street mode. I know a great t-case guy that can build you whatever you want...twin-stick conversions...creeper gearsets...etc. Gear or Chain driven.

If you wanted to keep the BW-3393/3394, then you would have the same issues this guy is having...some sort of custom 5-bolt tailshaft, and custom input shaft. Easier to just swap-in the 205...its way stronger, and you would get the 2WD mode all of us solid-axle guys want.

NV-4550 can be done, my wiring swap harness guy has done numerous harnesses and programming for 5cyl auto to v8 manual swaps and just auto to manual swaps. As for the t case the only hold up is the VSS right? Thats the only plug that goes into the t case. I saw an NP241 and the VSS worked but I am not sure how much stronger the NP241 is...if at all.

Sorry for the hijack. Carry on the 6l80e would be nice for 5 cyl guys, lower first gear for so more umph off the line
 

ReconH3

Guardian Angel
Messages
2,288
Location
Raleigh, NC
I'd go Atlas. I know it's not a problem to find adaptors. It's the electronics I'm worried about.


"Ex Umbris Venimus"
 

Ryan212

Well-Known Member
Messages
144
Location
Orlando
You may want to check with hptuners to see if you can license a hummer with a T43 trans. Their licensing structure may not allow it, as they require the vehicle to be a valid vin/OS pair. With other tuning solutions, this is not a concern.

not to throw this off subject, but if you go with an atlas2, make the sticks come out somewhere other than the drivers side next to the console, My leg rests on the front stick when driving which takes some getting used to.


Ryan
 

adventr

Well-Known Member
Messages
500
Location
United States
From what I've read, HP Tuners doesn't look at/care about the VIN on the TCM. Only the PCM. I've got a thread started in their forum asking for clarification, but that forum is terrible. Will probably be 2 weeks before I get a response.
 

Ryan212

Well-Known Member
Messages
144
Location
Orlando
Yeap. Send an email to support I think they are only a week response time. I would say call them bUT they do not have a phone number
 
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