XXL, what do you personally do? Do you take your overdrive off when you are doing city driving?

 

Just drive your truck normally and dont be worrying about taking ur OD out or not, its not worth it, your trucks way to nice to need that abuse, Man I would cough up my nuts for that thing

 

Here's an old post that might be of interest
about OD.

I encourage others to repeat this experiment
or test
"the other side" of OD
by measuring MPG on the highway
like at 55 mph in 2nd, 3rd and OD gear.
You can learn a lot by measuring yourself.

Measuring MPG in those three gears
making a graph of the 3 points
and extending the line past the MPG measured in OD
will tell you what 3.21 or 2.96 differential gear would do
and looking the MPG difference between 3rd gear and OD
will tell you what 3.92, 4.10, 4.56 and 4.88 diff gears will do.

OD is valuable when the truck is lightly loaded at highway cruise.
You can leave it off when towing or hauling heavy loads.
It does not do much in city driving...just a little gain.
====

Here's the results of several tanks of gasoline I kept track of with the OD
either on or off in city driving. After each tank fill up, I alternated
keeping the OD on or off.

I have since made 3 more 300 mile long mpg tests in city driving since i
posted the original 6 tests. My test results now look like this:
-----------
OD turned off runs:

7-19-00 14.32 mpg Amoco87
7-29-00 15.17 mpg Amoco87
8-08-00 14.23 mpg Amoco87
9-08-00 13.53 mpg Amoco87
---------------------------------
average 14.31 mpg
Standard Deviation =0.67

OD turned on runs:
(these were run inbetween the runs above)

7-12-00 14.16 mpg Exxon87
8-17-00 14.25 mpg Amoco87
8-24-00 15.49 mpg Amoco87
9-01-00 15.03 mpg Amoco87
9-12-00 14.35 mpg Amoco87
-------------------------------
average 14.66 mpg

As you can see, so far the OD on/off difference seems to be small with a
slight 0.3 MPG edge to leaving OD on while in city driving.
That is about a 2% difference and may be due to 'scatter.'

Note also how much the MPG jumps around.
All realworld tests have 'random variation.'

The Standard Deviation of all 9 tanks of gasoline = 0.61
and the average of all 9 tanks was 14.50
so that 98% of the time
the MPG will 'naturally' be expected to jump around
in a range from 13.3 to 15.7

If I had done just two tests, and had by chance gotten the low 14.16 for the
OD on, and the high 15.17 for OD off, I would have falsely concluded that OD
on really hurts in city driving.

To get more reliable MPG numbers for Rams in city driving you need to do
multiple tests in a before/after/before/after sequence. Even better would be
to do SAE/TMC type IV testing with two or more vehicles following one another
'convoy' style.

Most fraudulent MPG improvement devices continue to sell because of this 'jump
around' MPG during normal driving.

If a MPG device DOES NOTHING AT ALL, out of 100 people who try it, 50 will
find that their next tank of gasoline got them better MPG, and they will then
boast what a wonderful device they just bought.

Out of the 50 who get worse MPG on the next tank, quite a few will be a little
ashamed they got gypted and stay quiet, and only a few will be brave enough to
post that the device is a fraud. Some of these will say: "Maybe I did
something wrong and I will check the MPG on the next tank and will drive more
carefully." Half of these will "by chance" find better MPG on the second tank
and get the percentage reporting better MPG with the worthless device up to
75% !