Overdrive, that is a good point.
Can you feel it shift through all the gears into OD?


"Ed H." <edo.hart (AT) verizon (DOT) net> wrote

"Picasso" <Picasso (AT) gmail (DOT) com> wrote

No shit?? Maybe by service he meant a set of plugs/ wires or perhaps he has
leaves in his air cleaner housing. Maybe he has real aggresive tires on it.
Who knows? The op doesn't give any info.

"Picasso" <Picasso (AT) gmail (DOT) com> wrote

I'm not sure I follow your statement. The OP is asking about a difference
of 37% max (290 miles vs. 400 miles on a 26 gallon tank), not the almost
100% increase you suggest with a 10 mpg gain. Of course it would be helpful
to know what the actual MPG is, rather than the range on a "tank" of gas.

To wmiller2502 (AT) yahoo (DOT) com, have you calculated your actual MPG, of do you
just fill up when the gas gauge indicates you are low and compare how far
you have driven since the last fill up? It may be something as simple as
the gauge indicates low when you have several gallons left. From your post
of MPH vs. RPM it sounds like your OD may not be engaging, which I don't
think would account for the kind of MPG loss you claim, but real world MPG
numbers may tell a different story.

On Dec 13, 9:55 pm, "Ed H." <edo.h... (AT) verizon (DOT) net> wrote:
Ok, I have stock tires on the truck and I only know that when I fill
up the truck, it will take 23 to 24 gallons and I am getting around
290 miles from it. It may be normal. I was just asking if it is. I am
certain that I should be turning less rpm's then 2200 at 70 mph. The
truck is all stock. I just bought the truck (used) with 60k miles. Gm
said they did a complete "sevice / checkup" before the truck hit the
used lot. So I am assuming that they checked the filters, oil , etc .

On Dec 13, 9:55 pm, "Ed H." <edo.h... (AT) verizon (DOT) net> wrote:
Also, when I press the overdrive button, the enginge does not increase
in rpms like my old ford. A Gm mechanic said that is perfectly normal
for it to not increase rpms. But I don't know.How many gears should I
go through before i hit overdrive?

wmiller2502 (AT) yahoo (DOT) com wrote:
always Remember, Some people Will Tell u anything, Especially what Gas
milage they are Getting..
They may be getting less than what you are , but Donnot want to admit
it and Then they Tell u they Get better MPG than you do.

<wmiller2502 (AT) yahoo (DOT) com> wrote

First off, This is a Chevy and not a Ford so you're not hitting an
"overdrive" button on the end of the shifter - it's the "tow/haul mode"
button if just clicked once quickly. And No, it won't change your RPM's
because all it does is change the shift points between gears as you
accelerate and run up through them to finally arrive at overdrive.

If you really want to disable your overdrive, press and HOLD the tow/haul
button - but be prepared to see a sharp rise in RPM's when you do (I don't
suggest doing at highway speeds). At that point you should also see a light
on your dash with OD and a line through it indicating that the overdrive is
disabled.

I can't say if 2200 rpm is too high or just right - my Silverado is a 2500HD
with the Duramax and Allison so what I get won't be comparable to what you
should get. However, I get 500 miles on a complete 26 gallon tank of
diesel - or I did before I went to larger tires. I have a speedo error now
and haven't remeasured it. There are three things to check when you see
mileage like yours: 1) a basic tune up with plugs, air filter, fuel filter,
pcv valve, etc. 2) make sure your torque converter is locking up at highway
speeds; and 3) check your rear axle ratio. If you have a 4.10:1 rear axle
for towing then you are getting the mileage I would expect to see. But if
you have a 3.73 or lower ratio then you've got an issue here.

To check if you torque converter is locking up properly, you can drive along
at a steady 50mph on flat terrain (the converter should be locked up at this
point). With your right foot still on the gas, use your left foot and
lightly press your brake pedal - not firm enough to slow you down but just
enough to activate the brake lights. You should see a 200-300 jump in RPM
indicating that the converter is unlocking. If you don't see the jump then
it may not be locked up to begin with.

Cheers - Jonathan

On Dec 13, 10:25 pm, wmiller2... (AT) yahoo (DOT) com wrote:
Your fuel tank is a 26 gallon tank, you have a 5.3l 1500 crew cab, 4
wheel drive. The 2008 version is EPA rated at 14 city, 19 highway.

You have not told us what rear gear you have, you have not told us
your driving habits (all city, all highway, mix), you do say you have
a light foot. You have not told us at what point you fill up,
completely empty, 1/4 tank etc. So this is the best you are going to
get for an answer.

A 26 gallon tank at 290 miles is approximately 11.5 MPG, so yes, you
seem to be a little off from what it should be.

As a comparision, with mine, with the only differences being year and
that I have the extended cab, I am getting around 350 in the city,
which puts me closer to the EPA rating.

On Dec 14, 9:11 am, azwiley1 <wiley... (AT) yahoo (DOT) com> wrote:
I fill up when the light comes on and the miles are city and highway.
I do not know what gears I have. How can I find that out ?

wmiller2502 (AT) yahoo (DOT) com wrote:

Me thinks this is your problem, there is no overdrive button. OD is another
notch on the shift lever, the button is two/haul mode. If your running
around in tow/haul mode that could account for the low mpg.