4Le65 swap Can I swap to a 6 speed auto?
 

I have a Silverado SS 2003. It comes with a 4L65E with a supercharger.

Its about time to rebuild the tranny and I am trying to look at my options.

I would like to get a little better gas mileage and was wondering how much work it would be to go with a tranny that has more gears ( basically a new GM tranny with more gears 6 speed hopefully)

What all would have to be done?

Its not a simple bolt in. The 6 speed needs a separate controller. You may be able to get a stand alone controller and harness from some one like Speartech or you may have to do a custom swap using the harness from an E38 ECU with separate T43 controller and piggy back the original ECU.

If you are doing it for the mpg savings, you will probably have to drive it 10+ years to break even on the cost over rebuilding the 60E.

Yea thats what I am being told. Plus they are telling me that they use the same ratio .75

Ole well guess its time for a rebuild.

6sp is
1-4.027
2-2.364
3-1.532
4-1.152
5-0.852
6-0.667
R-3.064


Compared to a 60E
3.06
1.63
1
.70


80E
2.48
1.48
1
.75



Just to give you an idea of what your looking at.

Are both 6 speeds the same ratio's???

As far as i know..
similar to a 60E, 65E, and 70E all the same, except they arent :jest:

Found this:



The 6L90 transmission is slightly longer and taller than a comparable configuration 6L80 due to it's beefier internals. GM states, ". It is a heavy-duty version of the 6L80 six-speed automatic, with a strengthened input gearset which has two additional pinion gears for six total, and a strengthened output gearset, that uses wider gears than the 6L80. The 6L90 flexibilty extends to the clutches where the 6L90 has one more clutch plate than the 6L80 in each clutch for heavy duty applications. "

The 6L90 case is about 1.4" (35mm) longer than the 6L80 case.

AWD/4WD Transmission-bellhousing to end of output shaft (bellhousing to end of case)
4L70: 26.875" (22.25")
6L80: 27.125" [+.250"] (23.3")
6L90: 28.625" [+1.750"] (24.7")
4L80: 29" [2.125"] (26")

"6L80 weight
Transmission weight:258mm converter: Wet: 94-96kg ( 207-211lb )
Transmission weight:300mm converter: Wet: 102-104kg ( 225-229lb )

6L90 weight
Transmission weight: w/ 300mm converter
Wet: 109kg ( 240lb ) estimated

4L60 weight
Wet: 74 - 88.5 kg (163.2 - 195.0 lb)

4L80 weight
Wet: 115 kg (254 lb)
"

I see stick info!!!!