Since a few have asked for 6l80/90 tech on my personal build thread I’ll start here. The 6l80/90 is a clutch to clutch trans which is different from the predecessors.
More gears = more betters in my opinion….to a degree
1st gear - 4.03
2nd gear - 2.36
3rd gear - 1.53
4th gear - 1.15
5th gear - 0.85
6th gear - 0.67
Reverse - 3.06
Most 4 speed transmissions are in the 2.4X-2.8X range. The 4l60 is considered to have a very deep 1st gear for a 4 speed and it’s 3.06, this is much deeper than that. This will allow you to get away with less low range or less gear in the diff or just have very low gearing
Years - late 2005 (2006 model year, only in cars) to present day.
They really became common place in all GM vehicles by 2008. They have kind of been phased out by the 8/10 speed in the SUVs and trucks over the past few years but are still used present day in vans.
Tuning: there is so much to unlock with them. I personally haven’t done this but I was told you can assign each gate to whatever you want since it’s all electronic. So you can assign 1st gear next to reverse like a RMVB all from a computer.
I can state that I have personally tuned mine to start in any gear when in Manual mode. If I want a 3rd gear double low launch, I can do that from a stop. To do that for a 4l60/80/th35/th400 you usually have to open the pan and install a manual valve body.
Weak links, I hear the Torque converters in the early ones are not great. I have read that DOD (displacement on demand) made it worse, when the engine turns off to 4cylinder mode it shutters and shakes the TQ converter apart. Who knows, it’s all hearsay, I don’t have much personal experience on TC failing on the 6l80.
6l80 GVWR is 8600 lbs, GCWR is 14,000 lbs
6L90 GVWR is 15000 lbs GCWR is 21,000 lbs.
4l60E GVWR is 8600 lbs GCWR is 15,500 lbs.
4L80E GVWR is 16,500 lbs GCWR is 22,000 lbs.
I found this interesting, the GCWR is less in an 6l80 compared to a 4l60 but the 4l60 is the butt of all jokes for failure. The rated input torque on a 4l60 is significantly lower too. Just found this info interesting.
6l80 and 4l60 are basically the same length. I swapped mine in and literally had to oblong the transmission mount bolt holes and it dropped in. I’d say it’s within 1/2in. No driveshaft mods needed.
The 6L90E is 35mm longer (about 1.4in) and the case is bigger.
I am copying and pasting this from gearstar. I think they took this info from GMauthority, I’ve seen this comparison word for word on a few sites.
In addition, the 6L90 transmission comes with a reinforced input gearset with two extra pinion gears, i.e., 6 in total, and a strengthened output gearset that utilized wider gears than its predecessor. The flexibility of the 6L90 transmission extends to the clutches as the latter has an additional clutch plate in every clutch than the 6L80 for heavy-duty applications. However, a 6L90 version lacks the additional clutch plate that can match application requirements where appropriate. The 6L90 transmission differed from its predecessor’s long-standing GM 32 spline specification output shaft to efficiently handle the significantly increased output torque capacity.
Instead, it went for a large diameter of 29 splines for most truck applications. But some HD trucks and 2WD van versions had a 36 spline. This is why it is essential to be mindful of your output shaft version before you proceed with any adaptation. As mentioned earlier, the 6L90 transmission shares up to 75 percent of its components with its 6L80 counterpart. However, the case of the 6L80 transmission is 35mm longer than the case of the 6L80 transmission. Moreover, the 6L90 transmission case accommodates additional fasteners between the transfer case and the transmission for enhanced driveline vibration/noise performance.
They just mention the longer case but I’m told the case is a little harder to fit overall but that’s hearsay of a guy who’s done a 6l80 and 90 swap in the same make and model before.
I’d love to hear what kind of mileage you have gotten on your 6l80/90 even if it was in your daily driver. Each person I personally talk to I hear 220-250k miles on the 6l90. 150-200k on the 6l80.
More gears = more betters in my opinion….to a degree
1st gear - 4.03
2nd gear - 2.36
3rd gear - 1.53
4th gear - 1.15
5th gear - 0.85
6th gear - 0.67
Reverse - 3.06
Most 4 speed transmissions are in the 2.4X-2.8X range. The 4l60 is considered to have a very deep 1st gear for a 4 speed and it’s 3.06, this is much deeper than that. This will allow you to get away with less low range or less gear in the diff or just have very low gearing
Years - late 2005 (2006 model year, only in cars) to present day.
They really became common place in all GM vehicles by 2008. They have kind of been phased out by the 8/10 speed in the SUVs and trucks over the past few years but are still used present day in vans.
Tuning: there is so much to unlock with them. I personally haven’t done this but I was told you can assign each gate to whatever you want since it’s all electronic. So you can assign 1st gear next to reverse like a RMVB all from a computer.
I can state that I have personally tuned mine to start in any gear when in Manual mode. If I want a 3rd gear double low launch, I can do that from a stop. To do that for a 4l60/80/th35/th400 you usually have to open the pan and install a manual valve body.
Weak links, I hear the Torque converters in the early ones are not great. I have read that DOD (displacement on demand) made it worse, when the engine turns off to 4cylinder mode it shutters and shakes the TQ converter apart. Who knows, it’s all hearsay, I don’t have much personal experience on TC failing on the 6l80.
6l80 GVWR is 8600 lbs, GCWR is 14,000 lbs
6L90 GVWR is 15000 lbs GCWR is 21,000 lbs.
4l60E GVWR is 8600 lbs GCWR is 15,500 lbs.
4L80E GVWR is 16,500 lbs GCWR is 22,000 lbs.
I found this interesting, the GCWR is less in an 6l80 compared to a 4l60 but the 4l60 is the butt of all jokes for failure. The rated input torque on a 4l60 is significantly lower too. Just found this info interesting.
6l80 and 4l60 are basically the same length. I swapped mine in and literally had to oblong the transmission mount bolt holes and it dropped in. I’d say it’s within 1/2in. No driveshaft mods needed.
The 6L90E is 35mm longer (about 1.4in) and the case is bigger.
I am copying and pasting this from gearstar. I think they took this info from GMauthority, I’ve seen this comparison word for word on a few sites.
6L80 vs 6L90 Differences
To know the differences between the 6L80 vs 6L90, it is expedient to check out each of these transmission units.6L80 Transmission
The 6L80 transmissions heralded significant changes in the overall design of automatic transmissions fabricated by General Motors. All previous automatic transmissions by GM were based on hydraulic controls. These transmissions continually received electrical elements the more they modernized. But the 6L80 transmission was developed from the ground up as an electric-over-hydraulic transmission, complete with microprocessor control. The manufacture of the 6L80 began in 2005 and was released in most GM vehicles in the model year of 2006. The transmission lasted until 2016, available in 6L80 vs 6L90 versions.6L90 Transmission
GM introduced a stronger variant of the 6L80 transmission within a year, known as the 6L90 transmission, RPO code MYD. This version of the automatic transmission is 1-3/8 inches longer than its predecessor, the 6L80, with approximately 25 percent of the internal components of the new transmission differing from the old variant. In other words, the 6L90 Transmission is a heavy-duty version of the 6L80 six-speed automatic. Engine torque rating increases to a minimal degree, but the output torque rating of this transmission jumps up by almost 220 feet per pound to 885 feet per pound.In addition, the 6L90 transmission comes with a reinforced input gearset with two extra pinion gears, i.e., 6 in total, and a strengthened output gearset that utilized wider gears than its predecessor. The flexibility of the 6L90 transmission extends to the clutches as the latter has an additional clutch plate in every clutch than the 6L80 for heavy-duty applications. However, a 6L90 version lacks the additional clutch plate that can match application requirements where appropriate. The 6L90 transmission differed from its predecessor’s long-standing GM 32 spline specification output shaft to efficiently handle the significantly increased output torque capacity.
Instead, it went for a large diameter of 29 splines for most truck applications. But some HD trucks and 2WD van versions had a 36 spline. This is why it is essential to be mindful of your output shaft version before you proceed with any adaptation. As mentioned earlier, the 6L90 transmission shares up to 75 percent of its components with its 6L80 counterpart. However, the case of the 6L80 transmission is 35mm longer than the case of the 6L80 transmission. Moreover, the 6L90 transmission case accommodates additional fasteners between the transfer case and the transmission for enhanced driveline vibration/noise performance.
They just mention the longer case but I’m told the case is a little harder to fit overall but that’s hearsay of a guy who’s done a 6l80 and 90 swap in the same make and model before.
I’d love to hear what kind of mileage you have gotten on your 6l80/90 even if it was in your daily driver. Each person I personally talk to I hear 220-250k miles on the 6l90. 150-200k on the 6l80.
