6L80e 6spd Conversion

I'll update this later when I have more time, but I've been working closely with TBMS out of New Jersey to develop a 6L80e conversion for our H3s. :thumbs:
I've been wanting to do this since purchasing my H3, but just the other day my transmission bit the dust when the radiator trans cooler decided to give out internally! I figured now was as good of time as any to actually get this project up and going....


TBMS already has all of the electrical figured out, and sell a plug-and-play conversion harness. I have HP Tuners, and plan to develop the configuration to use on our E67 PCMs to facilitate control of the 6L80e.

We're just working on the mechanical side of it now. Good news, is that it's very close right out of the box so to speak. 6L80e output shaft length is perfect for our transfer case input shaft. Bad news is that 6L80e is 32 spline, and our transfer case is 27 spline. So, a new transfer case input shaft will be machined/heat treated.
Custom 6L80e transfer case adapter will be machined to the perfect length, thus allowing the transfer case to sit in the EXACT same spot as it does when attached to the H3s 4L60e transmission. That means NO driveline modifications/crossmember issues/transmission mount problems..ect
No clearance issues around the floorpan either (the 6L80e is quite a big larger O.D. than 4L60e).

*UPDATE - Transfer case input gear is too complex to manufacture (cost effectively). Solution seems to be machining the 6L80e output shaft to 27 spline.



Check out the TBMS website for more info on their 6L80e conversion harness and transfer case adapter: http://www.tbmsport.com/6l8090eswapcomponents.html




Here are some pics to show what a 6L80e will look like under the H3:



















These next few pics show the shaft engagement. The 6L80e shaft (32 spline) is a bit larger in diameter than the transfer case input shaft (27 spline).

















These pics show the shafts isolated from the rest of the assembly. The transfer case shaft is the one with the helical cut gear. You can see how it tapers down at the end nearest the transmission. Because of that, we cannot simply re-spine the transfer case shaft to 32 spline. There wouldn't be enough wall thickness left.
Instead, a new shaft will be machined, with the transmission end larger to allow for 32 splines.

Here are some pics of what happened when my radiator trans cooler gave out on me, and filled my engine full of tranny fluid and my trans full of engine coolant..........
























And here is my 6L80e that I will be using (2015 model with 8k actual miles):

Forgot to post up the gear ratios for each transmission.

4L60e

1st - 3.06
2nd -1.63
3rd - 1.00
4th - .70
Rev - 2.29



6L80e

1st - 4.02
2nd - 2.36
3rd - 1.53
4th - 1.15
5th - 0.85
6th - 0.67
Rev - 3.06



You can see that the 6L80e will be much better for on-road AND offroad use with that really low 1st gear. Reverse is also lower as well.

All I can say is Awesomeness!!!!

interested for sure. I just rebuilt my 4l60e with some internal upgrades but one day when I build up the 5.3 to put out some more power I will look into this upgrade.

Man, I really wanna see this happen!

I plan to drive the H3 out to Moab in November, so I've got to get it back up and going soon. Literally just waiting for that input shaft to be machined, then I'm back in business.

You guys that are local need to swing by and check out the shop if you're ever in Northwest Arkansas. Got some pretty cool stuff going on.

Hmm, I'm just over the border...
:huh:

Exciting things are underway, any idea on a estimated price?

I'm assuming that this will be able to work with both the I5 and the V8? Or would you need a different bell housing?

Ok, looks and sounds pretty good but what to do about the fact that the front driveshaft needs that clearance notch in the pan of the 4L60 and the proprietary internals to match? Will those parts transfer over to the 6L80?

Sub'd.

X2...what about the pan and valve body hack to clear the front driveshaft?
Frankly, I like the original layout (hoist pic)....that would be nice to use with a Ford solid axle and move the driveshaft to the drivers-side. Essentially trade the custom tranny/t-case work for the solid axle work.

How much clearance are you needing around the pan?
It looks to me like everything will clear just fine. Unless the front diff moves toward the transmission, but it shouldn't being ifs. The 4l60e pan sits a little higher than the 80e, but actual side clearance is just about the same.


Using the complete setup from donor vehicle would be possible, but I'd lose my 4:1 transfer case and then have to go through the trouble of axle swapping. Mine has front e-locker, so I'm pretty happy with the way it's currently setup.

*drool*

If the solid models are all accurate, it looks like the front driveshaft clears the 80e pan without modifications. The special internals on the 60e are to clear the special pan to clear the driveshaft. If the stock 80e pan clears, there is no need for any special parts.

This will not bolt up to an I5 either. Bell housing is Chevy standard pattern, not the atlas engine pattern, of which there were no OEM applications.

This has me pretty excited! I'm looking forward to seeing the finished build! I will be adding this to the list of things to do to my H3T.

Nice work, What brand radiator were you using when it failed ?

Very excited. Always thought the 6spd tranny would be much better than the 4spd


Sent from my iPhone using Tapatalk

CaseyS said:

If the solid models are all accurate, it looks like the front driveshaft clears the 80e pan without modifications. The special internals on the 60e are to clear the special pan to clear the driveshaft. If the stock 80e pan clears, there is no need for any special parts.

This will not bolt up to an I5 either. Bell housing is Chevy standard pattern, not the atlas engine pattern, of which there were no OEM applications.

Click to expand...

Looks like they have a bellhousing adapter to make this work for the I5: (about half way down page)

http://www.tbmsport.com/newseventslinks.html

Whats a rebuilt 6L cost vs. a 4L?

looks like the electronics, input shaft, and adapter is already up on the TBMS website. it's ready to go, then?

SedonaBound said:

Whats a rebuilt 6L cost vs. a 4L?

Click to expand...

Not very much.

As far as parts already being available:


Wiring Harness Conversion - Available currently
This replaces your T42 transmission controller, and adds an extension harness that runs down to the 6L80e. The 6l80e uses a T43 transmission controller, and that is located inside of the transmission itself. The conversion setup allows your PCM to communicate properly.


Transfer Case Adapter - Available Soon
TBMS has some adapters on the shelf, but these aren't quite "exact" for our H3s. The transfer case mounting holes need to be drilled out and clocked to the proper orientation. I'm providing data so that it can be done during the machining process, and will save everyone time. Also, I was able to determine the exact length required of this adapter to keep the transfer case in the OEM location. This will simplify install, and negate the need for driveline mods.


Transfer Case Input Shaft - Available Soon
Our transfer case is sort of an oddball. Most transfer cases use input shafts that could simply be "re-splined" to the required specs, but not this one. Someone chose to neck it down at the transmission side, so opening it up would lead to a very thin wall thickness. I was able to determine the correct specs for this new input shaft, so one will be available soon.
The place that will be machining these new input shafts is a shop that specializes in this sort of thing. Our transfer case shaft is pretty complex, and requires a lot of knowledge/experience/special equipment to machine. These will be heat treated to the proper hardness, and will be very durable.









This pic shows what the stock transfer case input shaft looks like:












This next pic shows what would happen if we were to just re-spline it to 32 spline. No material thickness left!










Last pic shows 32 spline and added material. Will be stronger than the factory shaft, but I don't believe the factory shaft was a weak link to begin with.

if the T43 tranny controller is in the 6l80, then why do we need a new one? isn't the 4l controller also inside the transmission? shouldn't we just need an ECM reprogram?

question 2: what if someone went full retard and swapped the trans and the engine and ECU that goes with it. then we would just need the hard parts, right? it would all talk to the gauges and stuff? it would just be a matter of wiring?