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First Drive: 2015 Silverado, Sierra, & Yukon 8-speed

Zane

By Zane
in Article & Review Archive (Pre-2019)

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Hutch65 Enthusiast

Hutch65

Posted
Posted

Doug Wrote "My truck came with 3.23 gears and the 4 speed (4.8 engine did not have 6 speed available), and was not a pleasant experience trying to merge into traffic on the highway"

 

Well Doug after reading your profile and your extensive experience, I'm left wondering why you ever bought such a heavy truck with that drivetrain. I have the same 4.8 and 4 speed and 3.23 rear in a shortbed standard cab Silverado and it is perfect! It has enough torque to accelerate the lighter truck just fine and if I want to stand on it she downshifts smoothly and takes off like a scalded cat...2nd gear runs to 99mph and then the governor cuts the power. I even pull a small travel trailer with it (3400 lbs.) and it handles it great. I leave it in 3rd all the time with or without tow haul mode and I only occasionally go down to 2nd gear under extreme conditions (Colorado Rockies). Then 4200 rpm or less scoots it right up the toughest of climbs at hp. robbing altitudes. Honestly don't know why GM sells our engine trans combo in double and crew cabs with that rear. It should have a 3.42 or 3.73 for the heavier applications if people insist on the 4.8. Your move to the 4.10s is much more in line with what it should have come with from the factory and a good choice. I get great mileage but I'm sure the heavier rigs would get their best mileage with an engine better matched for the load. Now if GM would put the 6.2 8-speed in a little truck like mine I might buy one for the grins.

Doug_Scott Senior Enthusiast

Doug_Scott

Posted
Posted

Doug Wrote "My truck came with 3.23 gears and the 4 speed (4.8 engine did not have 6 speed available), and was not a pleasant experience trying to merge into traffic on the highway"

 

Well Doug after reading your profile and your extensive experience, I'm left wondering why you ever bought such a heavy truck with that drivetrain. I have the same 4.8 and 4 speed and 3.23 rear in a shortbed standard cab Silverado and it is perfect! It has enough torque to accelerate the lighter truck just fine and if I want to stand on it she downshifts smoothly and takes off like a scalded cat...2nd gear runs to 99mph and then the governor cuts the power. I even pull a small travel trailer with it (3400 lbs.) and it handles it great. I leave it in 3rd all the time with or without tow haul mode and I only occasionally go down to 2nd gear under extreme conditions (Colorado Rockies). Then 4200 rpm or less scoots it right up the toughest of climbs at hp. robbing altitudes. Honestly don't know why GM sells our engine trans combo in double and crew cabs with that rear. It should have a 3.42 or 3.73 for the heavier applications if people insist on the 4.8. Your move to the 4.10s is much more in line with what it should have come with from the factory and a good choice. I get great mileage but I'm sure the heavier rigs would get their best mileage with an engine better matched for the load. Now if GM would put the 6.2 8-speed in a little truck like mine I might buy one for the grins.

 

When I bought the truck I was having huge issues trying to get into my car at the time due to my back. The only vehicle type that I could get in and out of was a pickup truck. At the time GM was giving very large rebates on trucks. I picked mine up for $28500 out the door. I was not working due to back, and had very limited income. Moving to a 5.3 engine would have given me the 6 speed, and the out the door price was over $2k more. At the time the only 2wd trucks on the lots were either SLTs or SL Nevada Edition. The SL all had the 4.8. This search was performed in all of Ontario. The rebates were expiring in a month, and you needed to take delivery before that date to get them. Dealer was already waiting over 6 weeks for customer ordered trucks. This dealer is the one I have always dealt with, and they are always straight with me.

 

Took a similar truck for road test, and it seemed to fit the bill nicely. Had decent acceleration, nice ride, and I could get into it easily. Was not until after back surgery that I started to notice issues with power and how the trans shifted. It was too late to go back. With the near $12k off list price on the truck, trading in value was not high enough to offset the increased cost on a different truck. I will be putting some form of forced induction on it this winter sometime.

2017SierraSLT Senior Enthusiast

2017SierraSLT

Posted
Posted

I absolutly love driving my 2009 Tahoe LTZ with the L9H 6.2L engine, but really get tired of the lazy shifts.

 

Wish I could transplant the new 8 speed or even the new controller in mine..

 

But the good part is I can dust the GOAT & TRD trucks with a soccer mom Tahoe :crackup:

 

TC

 

I was not impressed with the 6 speed trans in my '13 Sierra. Once I tuned the truck, and changed the shift quality/shift points with my Diablosport Intune tuner, I was happy with the results. It does not feel like the same truck, fortunately!

LongrangeLauber Senior Enthusiast

LongrangeLauber

Posted
Posted

The six speed is a bit sloppy (dad has 09 Silvy) but he has almost 180k on it and it hasn't slipped and drives like it did from day one. Wasn't that fortunate when he had my truck with the 4 speed. Replaced trans at 150k and then I replaced it a couple times (crappy rebuild guy, finally dished out the coin for a performance trans)

 

Sent while in 'Murica...

InertiaFaze Enthusiast

InertiaFaze

Posted
Posted

Anyone know on the 8 speed which (M) gear is the highest you can put the gear selector in and still not have AFM kick in? On the 6 speed its M5.

 

M7.

  • 3 weeks later...
super6 Enthusiast

super6

Posted
Posted

Isn't the 6 speed trans tunable by Black Bear? I know the tune on the 4 speed trans from Black Bear corrected all the shifting complaints I had with my 2010 Sierra EC with 4.8 and 4 speed.

Blackbear is THE solution here for your tranny woes. I had my 2009 5.3l tuned...totally different truck (in addition to engine tune), the tranny was no longer confused, sluggish, or problematic on the dreaded rolling "re-acceleration". Then, I got a '12 6.2 w/NHT pkg. First thing I did was have Justin work his magic on it. I am one year in and 30K miles...not a single problem...tranny is perfect, crisp, responsive, intelligent, aggressive when it knows I want it to be...the real deal. After 2nd truck (and all you 5.3l owners with the 6speed...you NEED to do this, it will make your truck fun to drive again, much cheaper than a '14 or '15) being tuned by Blackbear, I am sold. Worth every penny in my opinion.

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