Anyone have a GM 5.3L w/Fuel Managment and 6 speed

[Blue_Goose]

transmission...?

I've been eyeballing either a 2011 Silverado 1500 or a Sierra 1500 (LT or SLE) with the above config......

I've read that a lot of people have not been happy at all with either the Furl Management part (4 cylinder mode conks out above 70 mph) and that the 6 speed transmission is very clunky and actually surges forward sometimes while slowing...

I would think if this was a huge issue that there would be more of a buzz or outcry??

Anyways any info appreciated


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[NHGUY]

I'm curious how people like the Chrysler HEMI MDS system....I cant imagine these huge,overweight road hogs are in 4 cylinder mode very often.With all the aero drag they suffer,any multiple displacement system on a truck or full size SUV seems like a waste.

 

[Blue_Goose]

I think the supposed main factor is supposedly better mpg on the highway when all 8 cylinders are not needed for cruising



I rented an Impala that had it with the 3.9 engine and I got decent mpg taking it from Vegas to Oatman AZ avg between 75-85 mph and got close it not over 30 mpg when in 3 cylinder mode



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[ArrestMeRedZ]

I bought a 2011 LT 1500 4WD with the 5.3/6-speed (All Star Package) on 1 Oct. I've since driven it around town and on a 1100 mile trip.

Driving has been urban (Vegas), high desert (Nevada), mountain (Tahoe) and flat lowlands (Central Valley, CA). While breaking it in, I drove a bit slower than my usual. Varying the speed, but keeping it normally below 65, I got 21 MPG on the trip. Once I passed 500 miles, I picked up the speed at the expense of about 2 mpg.

I monitored the active fuel management on the trip quite a bit. It was normally in 8-cyl mode, with excursions to 4-cyl mostly when going downhill, or decelerating.

I found the transmission very smooth (I'm used to a manual in everything else I own), and found the selectible shift manual mode very useful in the mountains for compression braking.

For a heavy duty 1/2 ton 4 WD extended cab, I can hardly believe the combination of power and fuel efficiency.

 

[MrHorspwer]

While I don't own one, I have spent a lot of seat time in AFM 5.3L GM trucks. Yes, the AFM tends to be pretty much gone by 70 MPH, except for deceleration and downhill moments. If you're really in tune and are really paying attention, you can feel it switch from 8 to 4 or 4 to 8. It feels like an older, non PWM torque convertor locking or unlocking. Like I said though, it's only apparent if your looking for it and is easily tuned out.

One thing that I have found is that using the cruise control in the 35-55 MPH range really maximizes the AFM time, since accelerator inputs are minimized. I use the cruise control any time I can, even on surface streets.

As for the transmission, I'm at a loss. Given all the griping about GM's FWD 6-speed transmissions, the 6-speed RWD units have been excellent. I've never been disappointed in the performance of any of the trucks I've driven; they've all been smooth as butter. About five or six co-workers own newer GM trucks and I haven't heard a single complaint about the trans.

 

[Blue_Goose]

Good information guys! That makes me feel a lot better. There are some excellent deals out there right now on the 2011 Silverado and Sierra. Between the rebates and Military discount it is almost less expensive for me to get a brand new truck vs one a year or 2 old. (well maybe within a couple of grand or so)

afaik the only real diff between the Sierra nd Silverado is some exterior accents?


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[ArrestMeRedZ]

I had a local dealer really want to get rid of the 2011s and was able to get a deal using USAA pricing that was much better than GM employee pricing. Three days later, I went with my son to buy another, and they wouldn't do the deal again - had to go with employee pricing for the second one.
Not much difference between Chevy and GMC. Go with the one you like the looks of, or where you can get the best deal.

 

[buickman50401]

Originally Posted By: NHGUY
I'm curious how people like the Chrysler HEMI MDS system....I cant imagine these huge,overweight road hogs are in 4 cylinder mode very often.With all the aero drag they suffer,any multiple displacement system on a truck or full size SUV seems like a waste.

My folks seem to like it in their 2008 RAM. Helps a bit on the highway but more in town in their experience.

 

[Blue_Goose]

I read on a GM forum that a software update addressed the surging and hunting of the transmission...has anyone had this update done?



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