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The Chainsaw · 03-15-2016, 09:10 PM

Skip the GV unless you have 4.56's or higher with a 30" or shorter tire.

Drove my dads 2007 suburban for the last week on a roadtrip.

6.0 engine
4L80e transmission
3.73 gears
245/75r16 tires

Got better mileage on flat ground going 70mph than 60mph. 60mph was 1900rpm and even the 6.0 was wanting to downshift on most hills. The 8.1 will be SLIGHTLY better at low rpm, but it still won't like cruising too much lower than 2000rpm even empty.

03-15-2016, 09:10 PM	#9
The Chainsaw Registered User Join Date: Nov 2015 Location: Orland, CA Posts: 103	Re: 4l80e+GV or NV4500+GV Skip the GV unless you have 4.56's or higher with a 30" or shorter tire. Drove my dads 2007 suburban for the last week on a roadtrip. 6.0 engine 4L80e transmission 3.73 gears 245/75r16 tires Got better mileage on flat ground going 70mph than 60mph. 60mph was 1900rpm and even the 6.0 was wanting to downshift on most hills. The 8.1 will be SLIGHTLY better at low rpm, but it still won't like cruising too much lower than 2000rpm even empty.