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6L80E questions

Kain

Kain

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have they figured out how to put an np205 to a 6l80e yet? Is it worth it to have 6 speed? Is it strong enough, like 4l80e?
what year did 6l80e come stock?

well i found one answer....

50-9551AB: GM 6L80E / 6L90E 6 speed automatics to the GM & Dodge NP205 Figure 8 Transfer cases. | Advance Adapters

Advance Adapter This adapter kit will adapt the New GM automatics 6L80E or 6L90E 4WD to either GM & Dodge NP205 Figure 8 bolt pattern NP205's. Kit 50-9551A, 6L90E adapter assembly includes new female 29 spline NP205 input gear and shaft, NP205 adapter ri...
www.advanceadapters.com www.advanceadapters.com
 
I believe they started in 14 with those. They are very strong with the right programming. Think 1000hp 10sec 1/4 mile strong.
 
trying to gather info and a wish list, so far the controllers out now are below that i can find
and looks lik 2000 dollars more than a 4l80e

COMPUSHIFT Transmission Controllers | Advance Adapters

A New Standard In Transmission ControlThe COMPUSHIFT Sport and Pro by HGM Electronics brings you the world's first smart phone integrated transmission controller. Smart Phone / Tablet / Computer Integration: COMPUSHIFT Sport and Pro are the first sma...
www.advanceadapters.com www.advanceadapters.com

stores.lsxeverything.com

6L80E/6L90E Standalone Controller

GM 6L50E 6L80E 6L90E TRANSMISSION CONTROLLER W/HARNESS
stores.lsxeverything.com stores.lsxeverything.com
 
They specialize in the 6.5 but it should work behind any engine. Quadstartuning.com Not cheap though around $2500. But supposed to give tow/haul and the tap shift options besides just a standard shift program.
 
I think a 6l80e or 6l90e would be great but they are pricey. Lower first gear plus 2 overdrive gears. Our 2008 2500HD has one.
 
i would go junkyard hunting its the only way i could afford it but the controller is 1000 bucks the adapter kit is 706.54 the converter would be 700 bucks from summit 350 from amazon (cheaper but do i trust it) still trying trans mounts, like what to use

4l80e is strong stock, cheaper on cost converter is cheaper 175 bucks adapter kit is 680 but transfer case needs machining and mount is same as one i have or it looks it. contoler is 600 and change.
 
The 4l80e is a big transmission, but I feel like the 6l80e is even bigger. I'm referring to how big around it is. I'm sure it's probably longer too. Makes me wonder if you'd have body clearance issues in a K5 installing the 6l80e.
 
SUVs were phasing in 2009. Trucks started in 2006. So there are a lot out there.

1st gear more than 4:1 and two overdrive gears. 2nd gear is almost like 1st gear in the 4L80. I think this is part of why they started skipping low range in transfer cases. The factory programming sucks, but it's nice hardware.
 
Last edited:
mrk5 said:
The 4l80e is a big transmission, but I feel like the 6l80e is even bigger. I'm referring to how big around it is. I'm sure it's probably longer too. Makes me wonder if you'd have body clearance issues in a K5 installing the 6l80e.
Click to expand...
6L80 or 8L90 both fit fine.
 
Blue85 said:
SUVs were phasing in 2009. Trucks started in 2006. So there are a lot out there.

1st gear more than 4:1 and two overdrive gears. 2nd gear is almost like 1st gear in the 4L80. I think this is part of why they started skipping low range in transfer cases. The factory programming sucks, but it's nice hardware.
Click to expand...
Do you know the ratios for all 6 gears? I couldn't find them in a half-assed search. We just bought a '13 3500 Express with a 4.8/6L90/3.42 combo and it feels every bit as strong as the 6.0/4L80/4.10 combo in our '00 2500 Suburban. So far, it seems like a very good transmission. Well worth the added swap cost over a 4L80.
 
6L80/6L90 is a good trans and lots of guys drag racing them in 700-800hp+ range with only upgraded converters, however the tuning is everything to making the trans live a long life. The stock tuning is very lazy for comfortable early shifts and gas mileage by locking the converter everywhere. The problem there is the stock converter lock up clutch isn't that big and stock tune allows for some converter slip when locked in an effort to minimize drivetrain harmonics or vibrations. The slippage under the stock tune can burn up the stock converter clutch sending clutch material into the pan taking the rest of the trans with it. That's really it's biggest weak point. Most tuners are turning off converter lockup in 1-4 and only locking in 5th and 6th. This seems to make the stock converters last. I personally prefer to have low throttle lockup in 3rd and 4th as well but I zero'd out the converter slip tables. With some changes to shift timing and speeds it's really made my 6L80 much more lively to drive.

As far as controlling a 6L80/90 your cheapest and best route is to swap a GEN IV LS that came with a stock 6L80/90 because the trans has a separate internal TCU that must communicate with the stock computer in order to be happy and allow it to shift.
 
I have a 8L90e in my L86 2015 Sierra. It ate two torque converters, one reaction shell, four fluid changes, three radiators, one VLOM and a set of lifters, and a set of injectors. Everything was covered under warranty except the injectors. Which I did myself, which was a PITA for a fat guy.

It was mostly first year struggles I think. I mean, it's a ZF HP8 with a GM sticker on it. Clearly not designed for high torque and high resistance like a truck. It's designed to move around low resistance cars and shitbox vans with tiny engines.

Mine had the first torque converter that it wasn't supposed to have leave the lot with, but I picked it up before it was even portered by the dealership. I think it ate itself by 23,000 miles but started pulsing (20-60rpm slip, pulsing about once every .45s while in 8th gear at 1200-1600rpm, felt like rumble strips) by 8,000 miles. It also had a TSB for a reaction shell that didn't eat itself until 85k. The second converter got cooked because even with the second redesigned transmission fluid the TCC still slipped too much for the two speed pump to keep it locked up at high torque/low RPM.

I wouldn't think much of buying a 2017+ 8L90e. The hard part problems were fixed then, especially with the new fluid that can handle moisture better.

I had a L76 (aluminum 6.0L)/6L80e in my 2009 Silverado. There is no way in hell I'd pick a 6L80e over a 8L90e. Especially now that the 10 speeds are out and drove down the cost of the ZF-GM 8 speeds.
 
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