4l80e vs 6l80e vs T56 Swap

[novajess1972]

In the market for overdrive tranny for the 72 Chevelle. Currently 454 BB (450hp/500tq) backed by a TH350.

Couple questions:



1. Any reason why I wouldn't go with a 6l80e over a 4l80e? I sometimes find them attached to used LS motors or later truck motors (LQ4, LQ9, LY6, etc). If I purchased the motor and tranny (6l80e) altogether, are there any issues with swapping in straight in with the motor?

Not very familiar with the 6l80e so just thought I'd ask the question.


2. Are there people out there willing to swap their 4l80e for t56? the reason I ask is because I come across quite a few more LS1/LS2's that are attached to t56's. I'd rather not go through all the trouble of converting to manual setup, so I would want to swap the t56 for a AOD tranny. Then again, the money I would have to throw at the AOD computer controller might be about the same as the auto to manual conversion.


Thoughts? Suggestions? Alternatives?

[Sean Cooke]

I might be interested in swapping a 4l80e for a T56

[novajess1972]

I'll be sure to reach out if I snag a complete package.

I'm on the fence about doing a complete LS swap into the Chevelle...but am leaning toward just going with the AOD tranny since the swap really stretches my budget beyond where I had hoped.

[Sean Cooke]

It can be a good swap, great way to make your car reliably fast. It would be good to see the comparison between a BBC and or SBC Chevelle vs LS swapped Chevelle - cost per HP, performance, and road manners ...

[Steve Chryssos]

If you are keeping the BB Chevy, the 6L cannot be adapted at this time. It has an internal TCM that relies heavily on input from an LS ECM. As such, the 6L does not work standalone (at this time). Taking that out of the equation, the 4L is easier to install as it's dimensions are similar to TH350's and 400's. The 6L series is especially tall and might require a tailshaft conversion kit. The biggest challenge with 6L swaps seems to be on the harness and tuning side, whereas 4L controllers and tunes are well established. There are plenty of tuners and harness builders getting it right -- just have all of your ducks in a row BEFORE sourcing an LS/6L.

The 4L requires a standalone trans controller which comes with a plug and play harness. Depending on you you get it from, the controller also will come with a custom tune and comprehensive tech support. Comparatively speaking, the 4L will install itself and cook you dinner. The 6L offers the latest technology, but requires an LS engine AND a thinking cap.

[novajess1972]

Well, that certainly clears things up a ton!

[novajess1972]

Another question:

In my search for a 4l80e, is there a year model that I should look for that's better/more reliable/stronger or what have you, than other years? Someone told me that the pre-1995s are best.

????

[Steve Chryssos]

Glad I could help. The first 3 years are not as good as the rest. More so than most engineering exercises, automatic transmissions are evolutionary beasts.

[hifi875]

t56 all the way. alot more enjoyable for a fun car. for a everyday driver, automatic. speaking as a owner of a ls/auto combo, I want a t56.

[Steve Chryssos]

I like em both. The problem with autos is that people taking them as they arrive, instead of setting them up properly and applying the right calibration. If you ever get to Daytona, or we meet at an event, I'll be happy to let you drive my car. It's calibrated to anticipate my shifting, shifts are lightning quick but not harsh, the heavy duty lock up clutch feels truly coupled to the engine, and for those times when I'm smarter than the computer, the paddle shifter serves as an override. It's a systems approach as opposed to just having an "auto" and it's for real.

Each and every person who has hopped out of my car states: "Oh wow! that really is different!" None of this takes away from the visceral excitement of a three pedal car, but after eight years of tweaking, we're proud of the result. We're also happy to talk with you about your auto and help you tune it as best as possible by phone. No charge. Maybe we can improve your driving experience until the T56 arrives.

Thanks,
Steve