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4BT + 6L80e

CaseyS

CaseyS

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732
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Louisiana
Starting to collect parts for a new project. Following Aventr's path with the hardware side of things. Will be using a cut down 27 spline output shaft and a TBSS adapter. Software side will include a TCM-2650 standalone from Zero Gravity. I'm early in the process working through all the detail stuff. First one right now is torque converter depth differences with my flexplate setup.

Transmission here is a 2011 with only 40k miles that I scored for $800. I have to open it to get to the input shaft so it will get an internal inspection before it gets bolted to anything.

Details will follow as they begin to trickle in. Not in a rush yet on this, likely spring completion.

 
CaseyS

CaseyS

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Messages
732
Location
Louisiana
So today I was able to verify an import piece of the puzzle. The torque converter snout is different from the early 4L60e and the 4L80e to the LS style 4L60e and 6L80e. The Cummins flexplate and adapter is setup for the early 4L60e (700r4) and the 4L80e. The 4l80e was predominately found on 6.0L engines and those ran an undished flexplate. The newer LS based engines run a dished flexplate and run the newer style 60 and 80 converters. Here is my early style 60e converter.



Notice that the snout is almost flush with the converter pads.

Now here is the 6L80e converter



The snout projects 5/8" past the pads and the center is dished further out towards the engine. So I carried my converter down to PATC this morning and asked them to pull a flexplate out of one of their packaged kits to check the dimensions. Well it fits right on with no interference.



I now have a direction on modifications that will be needed.

First, the flexplate is drilled with a 10.75" bolt circle for the 700r4 (early 4L60e) and an 11.5" bolt circle for the 4L80e. The late style 300mm LS torque converters are all 11" bolt circle. When I'm ready to swap, I will have to pull the flexplate and have a 11" circle drilled in the flexplate. Either that or get the air grinder and elongate one set of holes to make the converter bolt up.

Second, the mounting surface of the flexplate is 1.0" from the face of the adapter. In the 6L80e, the torque converter pads are 1.0" from the bellhousing face with the converter fully seated. I will have to space the transmission out 1/8" to allow some takeup to pull the converter forward when everything is bolted in.

Even though the transmission is spaced out slightly, the relationship between the starter and flywheel is maintained so nothing will have to change on that end.

Here is the transmission spacer that I will need

https://www.summitracing.com/parts/...VFnh7hnBoybmrXbAHMTAnKy1v9bWQXVbrbxoCYLTw_wcB
 
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CaseyS

CaseyS

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Messages
732
Location
Louisiana
Yes, I am in the process of exchanging email with TBMSport now. It is my understanding that the R&D work was done on Aventr's build and they just need to crank me out another one. Another thing I am asking is if they have a 27 spline output shaft in stock that I can swap for a core when I pull mine apart. If not I will have to break mine down to pull the output shaft and have it sent off.
 
amrg

amrg

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IIRC adventr had an extra output shaft he was willing to give out. Getting a hold of him is another story.
 
A

atvspeed4

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massachusetts
Do you know if a 32 spline output shaft from 6l80E can be swapped into a 6l90E? I am planning on swapping in a 6l90e on my alpha and supercharging but would rather turn down a 32 spline to 27 than the HUGE 29 spline on the 4x4 6l90e as the heat treat is only so deep.
 
SuperBuickGuy

SuperBuickGuy

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atvspeed4 said:
Do you know if a 32 spline output shaft from 6l80E can be swapped into a 6l90E? I am planning on swapping in a 6l90e on my alpha and supercharging but would rather turn down a 32 spline to 27 than the HUGE 29 spline on the 4x4 6l90e as the heat treat is only so deep.
Click to expand...

Is the 6L80e 32 spline the same as the turbo 400 32 spline?
 
CaseyS

CaseyS

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732
Location
Louisiana
Keep in mind that a 90 is 1.5" longer than an 80. Check your dimensions carefully. This will most likely require cross member modifications, plus this will almost put the transfer case encoder right into the body fixed cross member. I'm not sure we have the room, plus any added strength of the 90 over the 80 would just be negated by a cut down output shaft.
 
amrg

amrg

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Will the 6l90 work with the Alpha ecu? Or more specifically, does the 6l90 have a 2008/2009 variant?
Aventr had a 6l80 from a 2011 model and it wouldn't communicate with his pcm. When he replaced the valve body with one from a 2008/2009 model year he was able to make it work as the OS for the tcm for that valve body (08/09) works with the alpha ecu. Newer valve bodies require an updated OS (2011+ for the 6l80 with 2010 being a mixed year) for the tcm which doesn't communicate with the alpha ecu.
 
CaseyS

CaseyS

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Messages
732
Location
Louisiana
Output shaft showed up yesterday. Sent it back out today to get resplined. Now I need to figure out if I want to take this trans apart when I get the output back here or let someone else mess with it. If I do it myself I will need the super size snap ring tool for the center support.

 
CaseyS

CaseyS

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732
Location
Louisiana
RamRod said:
oo so does this mean that you will have an extra output shaft soon?
Click to expand...

Yes it will. And if it helps I can send it straight to Moser for them to cut it and save the extra shipping leg to you. $75 core charge, that's what I have in it.
 
GreatDaneHummer

GreatDaneHummer

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Casey did you ever come up with a better throttle setup than the cable you ran in your video? If I remember correct it wasn't very responsive etc? Did you end up with an electronic connection?
 
RamRod

RamRod

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CaseyS said:
Yes it will. And if it helps I can send it straight to Moser for them to cut it and save the extra shipping leg to you. $75 core charge, that's what I have in it.
Click to expand...
Yup that sound good, PM me your details when you are ready or what ever and I will certainly take you up on this offer!

Are you still thinking of dropping your gearing down or will this swap make that redundant (iirc you have 4.56's and wanted to drop down to 4.10's)

Sent from my SM-G935W8 using Tapatalk
 
CaseyS

CaseyS

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Messages
732
Location
Louisiana
RamRod said:
Hot damn!.... still have those 4.56's?



Sent from my SM-G935W8 using Tapatalk
Click to expand...

Left them with 4speedfunk. He may still have them or he may have used them already. They were high mileage, 275k miles when they were pulled out.
 
RamRod

RamRod

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CaseyS said:
Left them with 4speedfunk. He may still have them or he may have used them already. They were high mileage, 275k miles when they were pulled out.
Click to expand...
Oh I think I remember that now

So are you going to try and figure out how to to the manual up down shift that the 6L80e is capable of doing in the Silverado's?

It would be awesome to gain that functionality!!!

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