"Revised" 6-speed

[Larry]

It makes sense GM Powertrain tweaked the trans calibrations to better match the higher torque Direct Injected engines but I tell you, the 6L80 and 6L90 calibration’s needed some tweaking badly. We just ordered a replacement vehicle for a 2013 Tahoe Z71 we ordered last summer and took delivery of last October. I HATE this Tahoe and it only has 8,000 miles on her. Between the way the Active Fuel Management on the sequential port injected 5.3L works with the busy shifting -low geared 6L80 trans combined with 3:42 gears makes for one jerky mess. The 2004 Tahoe Z71 we bought new and sold to buy this one was a smooth machine for over 130,000 miles. Not this 2013, unless you have it on cruise control the truck is constantly slowing down where you must keep tipping into the throttle to maintain speed, then when the engine comes back alive in V8 mode it feels like the trans drops a gear or two and jerks back to life. The other annoying thing is how the 6L90 seems like it doesn’t want to upshift when going slow through a parking lot and if you do a slow rolling stop and step on the throttle it jerks like an old truck launching around in granny gear. Not real thrilled with the ride quality of this Tahoe over the past Tahoe’s either but that is a different story. This is the 7^th new GM vehicle we bought new and 3^rd Tahoe but I will be so glad to get rid of it when the new vehicle comes in. I’ve driven a few ’14 Silvy’s and did not notice any of this busyness in them. The 14’s with DI seem to run darn near perfect and the AFM feels seemless.

 

Don’t worry, we don’t stray from the GM tree…..we ordered 2014 White Diamond Tricoat 2LTZ Impala and look forward to delivery in late October. The Tahoe goes away the day the Impala gets here, which I can’t wait. Maybe someday we'll consider another Tahoe (depending how the next generation Tahoe's look) but for now the family truckster will be an Impala for a few years.

 

I am also considering selling a cream puff 56,000 mile - 2001 Silverado HD ECSB 4x4 with an 8.1L and 6 Speed manual to buy a 2014 or 2014 Silverado 1500 LTZ/Z71. Hmmm, I really like the 14’s! GM Powertrain really did a nice job with the engine and trans in that truck. GM Design also finally pulled off the first good looking Chevrolet truck since the 2001/2002 HD trucks hit the market. Nice work GM! Glad you got the GMT900 days behind you!

[Daryl LBZ]

My trucks transmission does a few of those annoying things that you mentioned. I'll just have it cleaned up with a tune eventually. Cheaper than buying a new one.

[Larry]

An HD trans in a light duty truck would drive horrible. Too much parasitic loss.

 

 

I agree, an Allison would probably be overkill for a ½ ton truck but you would be surprised how well the Allison 1000 and 2200 perform behind a L96 6.0L. I’ve driven many trucks with that combination and there is no parasitic loss felt what so ever. A great performing combination!

 

 

 

[Badass69]

An HD trans in a light duty truck would drive horrible. Too much parasitic loss.

 

 

I agree, an Allison would probably be overkill for a ½ ton truck but you would be surprised how well the Allison 1000 and 2200 perform behind a L96 6.0L. I’ve driven many trucks with that combination and there is no parasitic loss felt what so ever. A great performing combination!

 

 

 

What trucks have you driven that run an allison with an L96? Obviously something odd because any 2500 or 3500hd has a 6L90E behind it...

[Daryl LBZ]

What trucks have you driven that run an allison with an L96? Obviously something odd because any 2500 or 3500hd has a 6L90E behind it...

 

Commercial vehicle maybe?

[Larry]

What trucks have you driven that run an allison with an L96? Obviously something odd because any 2500 or 3500hd has a 6L90E behind it...

 

Chevrolet and GMC are not the only nameplates in the world using GM Powertrain engines. Workhorse Custom Chassis – Navistar (the company I work for) and Freightliner (our competitor) both purchase engines and transmissions from GM Powertrain (and Allison). We built several thousand L96/Allison 1000 and 2200 stripped chassis for the package delivery industry (think bread vans) since 2010 when the 6.0L was finally certified to run with an Allison. Pretty good chance that packages delivered to your home or place of business delivered via UPS came on one of our trucks with a GM gas engine. Over the years we’ve used 4.3L, 5.7L, 6.5L, 7.4L, 8.1L, 4.8L and 6.0L engines in some rather unusual vehicles with odd transmission combinations that you would not find in a GM truck. We have been the largest consumer of GM engines outside of GM.

 

Prior to body install

 

 

[Badass69]

Interesting... not really lol. I figured you were doing something half ass custom. I don't deal with ups lol.. they are purolator outside cities here and use normal cube vans. I deal with commercial trucks too somewhat but they are diesels... not gas jobs.

 

We use lots of Gm 6 liters too not in Gm trucks... burning natural gas on compressors....

 

And lets not forget days past and present where thousands upon thousands of Chev small blocks powered equipment, generators, watwr pumps and whatever else. Like Massey Ferguson combines lol. Amazing where they end up.

 

[MikeNH]

Chevy and Chrysler engines were even used to power air raid sirens back in the day.

[2k11Silverado]

Hello MotoMedic – I know exactly what you’re talking about.
That was one of the first things I noticed when I first got my 2011 Silverado.
When stopping, it feels like my truck is getting thrown forward, counteracting
my braking. I HATE this!!!! I thought
this would improve over time due to these being “so-called” adaptable
transmissions. No such luck. It’s especially noticeable when you’re accelerate,
then have to stop right after. I can’t wait to get rid of my truck and get
something else. Curious to see how you feel about the Active Fuel Management?
Do you notice the slight “bump” when it switches from 4 cyl to 8 cly. Between the
bump and the transmission throwing us forward, it feels like the truck has a
mind of its own. FYI… I had a ’04 and it had none of the annoyances. Hope this helps.

[Stex]

Check into a drivability 89 octane tune. I gave up on mine and did such. Perfect no but much, much better. As for AFM I cannot tell when it went to and fro except for the DIC telling me so. Off now.

 

Do not want to tune but cut off AFM? Google Range AFM delete. Cheaper than new truck and will get you through tell the '14s settle down.