Drivetrain Advice

The LSAs with the 6L80 packages are not available but the stand alone engines are. Im going to order one. I am now intrigued by the 6L80 though. that first gear ratio sounds pretty tasty. anyone running one?

I have a 6L90. Basically the same thing. Just more heavy duty. They share ratios and like 75% of the internals. The 4:1 first gear is rad. I spend 99% of my time in midrange (2.4:1) in the tcase and it is about the same ratio I had with my 4l80 and 4.3 low in the tcase. Tap shift is rad for mobbing around and with the way my shift tables are setup I can start in 1-4. 5 and 6 are prohibited but I’ve never started past 2nd in midrange.

How is it controlled? How is it shifted? I can guess how tap shift is but is there a mechanical shifter. Winters? A morning of Google says you can make it work with earlier engines but I’m not completely comfortable with it

Mine is stand alone controlled with a PCS TCM-2650. Knowing what I know now, I’d have put a 58x reluctor wheel on the crank when I built my motor and converted everything to Gen iv architecture. I think that factory controls are far superior to this stand alone controller.

Tap shift can be done with any momentary switch as long as the circuit is correct to send the right voltage to the ecm. I bought a RADesigns kit that retrofitted to my winters shifter. But as I understand he doesn’t sell that kit any more.

OK I have been researching a little bit but much is over my head. The LSA should have the 56x reluctor on it will that mean the trans can just plug into the ECM and then both the engine and the trans can be tuned by a shop at the same time?

No 1:1 ratio seems odd.

6L90 is 29spl input Wouldn't be a deal breaker. Length would be within an inch.

I’m honestly not sure on what ecm is needed as I have experience with a stand alone setup. Yeah the output is 29 spline like an Alison rather than the standard 32 spline. It’s larger diameter too.

This is all from memory, so do your own research to confirm first please.

Early 6L80E (2007-2010?) TECHMs have to be matched with the same year engine ECM. Later years can be mixed and matched to work together with flash programming like EFILive or HPTuners. Later years (2010+) can also be flashed for a lot faster/snappier shift timing. Complaints from corvette owners about 6l80 shift timing compared to BMW DSG dual clutch shift timing. This resulted in a redesign of the shifting tables and programming that drastically improved performance with no changes to hardware.

To get tap shift working, with the stock computers, there are a things needed.
A resistors with specific values, a momentary switch setup and then flash programming the TECHM to enable it. It's not too difficult to find the corvette 6l80 wiring schematic showing the resistor values if you search around. Some people have even pulled the Malub SS/Cobalt SS console shifters with the tap up/tap down buttons and retro fitted them. Going this route can eliminate the need of a gm column shifter or third party switches.

Holley can do the 6L's with a Terminator Max X setup.
My buddy used an Aftermarket shifter for a Powerglide (Winters) and electric tap shifters on his steering wheel. Basically just an up button and a down button, nothing too fancy.

So far I’m loving my 6l80. Not sure if atlas has a 29 spline input, so you may be better off with the 80 and 32 spline. I can say my first gear is about worthless on the street. It’s too low. No dirt time yet but I imagine it will shine then.
All good advise here so far and I’ll just add to make sure your suspension plan matches your drivetrain plans. I’m quickly finding out I’m under suspended.

I’m definitely not going to be under suspended. Atlas does have an input shaft. 300m HD one so I can keep the same strength. This jeep won’t care about the street the two overdrive gears will never be engaged. I’m debating whether the lower first is worth the trouble. I think it may be. I know it can be made to work. It may actually be cheaper than my original plan. I think the complexity may not be as reliable though

Trying not to go Holley terminator but I realize it can do everything