..an my truck is so much more fun to drive than b4 the gears...

 

As always, find out for yourself.

If you take along about 400 lbs of weight in the form of a couple friends,
and find a 'good' dealership with a 'curious to learn' salesman,
it is easy to compare a new 5.7 4x4 Ram with 3.55 or 3.92 differentials
to a Dodge Ram Powerwagon 5.7 with 4.56 differential gears
by resetting both trip computers and going on a city/highway test drive
while talking to the other vehicle with cell phones.

If you have a friend with a new 6 speed Toyota Tundra 5.7
bring him along too to be in the 'convoy' of test trucks
so you can see what an overdrive ratio of 0.588 combined with a 4.10 differential does.

Since the V6 Rams have different diff ratios depending on automatic vs manual trans it is relatively easy to do a convoy test.
The difference between 6th gear and 5th gear (1.00/0.79 times 3.21)
makes like a 4.06 differential had been installed
and if you downshift to 4th gear (1.23/,79 times 3.21)
it is like a 4.99 differential.
If you commonly drive at 70 mph find out what MPG you get when in these three different gears before laying out the $ on a diff change.

Say your local dealership and salesman is afraid to do these types of tests?

You now know that is a bad dealership and it is worth while to travel a bit to find another.

Of course, you can run this same type of mpg test trip with friends who own different trucks. Don't dismiss the convoy idea...because it is the only practical way to keep the pickups in the same wind, temperature, speed and pavement conditions...which is a critical detail.

 

From today's (Thursday) Wall Street Journal



note how the numerically lower gears improved MPG 4%
and low rolling resistance tires improved MPG another 4%

This is exactly what ex-Chrysler vice president Bob Lutz did when GM hired him to improve their pickup, and remember that this is the same 'Maximum Bob' who ordered the design of the V10 for the Viper and was the guy who gave the OK for the new Hemi heads on the 5.7 before the Germans 'retired' him with a $34 'golden parachute.'

 

Damn man, I dont care about downshifting, I know what I can do by downshifting. I WANT TO GET OUT OF THE LINE FROM DEAD STOPBETTER. I hate shifting to first gear and having the truck bounce trying to move forward while I have the pedal down to the floor. I have tried the slowly accelerate and the flooring accelerate and the truck moves slowly. I cant pass or make a turn at the light because it takes 10-15 seconds to get moving. I dont want that. I know its a V6 and dont need to be reminded. You keep talking about highway, but I dont work or live driving on the HWY all day. We all city folk here with about 30 streetlights in a straight mile of road. So I am sorry Hank, all your talk about convoy, highway, mpg, Tundra, 4.56, its just not answering my question.

 

In one of the Diesel magazines
either this month or last
there was an article about a 1996 Cummins Ram
making more than 1500 hp in drag racing setup
with a automatic transmission built by Suncoast.

This Ram was using 3.55 differential gears.

Why?

A key 'principle' of drag racing is to try to make your launch at the torque peak of the engine full throttle with the tires creating maximum traction.

Maximum traction to move the vehicle forward comes not from a wild 'burnout' but from a controlled 2-5% slip of the rubber against the pavement.

So the first question to a Ram owner is:
if you have a 5.7 Hemi can you make a launch at full throttle and 4200 rpm?
{of course you can't....your rear axle will be hopping like crazy}
and 2nd Gen Rams can't make a launch at 3200 rpm with a 5.9V8 either.

What does an experienced drag racer do about this?

First, he makes some mods to the suspension...many mods have been tried.

Second, he goes out and buys the largest/widest rear tires with the best rubber compound....as much as his budget or the class rules allow.

Third, he changes the rear differential ratio
(or first gear inside the trans)
so that he (or she if your last name is Force or Muldowney)
can barely break the tires loose at full throttle on dry pavement that already has lots of rubber sticking to it.
{notice there is a water bath to heat up the rubber...not dry}

The more torque your engine makes near maximum
the LESS numerical differential ratio you select
....because you CAN'T MAKE USE OF IT
if your rear wheels are spinning wildly

If you can fit better traction rear tires
then you can go up in numerical differential ratio

I will leave the second key principle
'know your rpm as you cross the finish line'
for y'all to figure out
...it is surprising how few know this one either.
{Hint: do you want to finish halfway through a gear range?}

Click the 'search' button here on Dodgeforum (or another forum)
and enter "4.56"

You will get hundreds of hits.

In 90% of those hits you will find a teenager
{or someone with a maturity similar to a teenager}
who 'loves' his 4.56 diff gears because he can now
'burn rubber'

In perhaps 5% of those hits
you will find a post where someone writes about whether his truck can now launch properly at full torque and full throttle with the torque converter doing its job properly.

Every now and then there will be a common sense question about whether the 4.56 gears let him finish the quartermile making best use of the gears in his transmission.

Every now and then
a honest beginner will ask the correct question:
"Should I really be ending up in overdrive gear at 3100 rpm for a good quartermile run?"

What percent difference between each gear does there have to be
so that a 4.56 diff can 'match' the transmission?

Why does a Tundra have 6 gears in their auto?

Why do all of the latest model Mercedes have 7 speed autos?

How much equivalent gear ratio does the torque converter create at full slip?

Your fathers and grandfathers (not me)
found all this out
and would love to give it to you as a gift
that you too would also pass on.

If you don't have this knowledge
your country is in danger.

 

Hank. . .I'm gunna agree/disagree with you on a few things. . .Ive got 4.10's in my truck. . .WAY too high if you ask me, but I can pull trees out of the ground by the roots if needed. having 3.73's or even 3.54's would be better. Why do I have 4.10's in my truck, it came like that from the factory. now with eltupac, 3.92's or even 4.10's for him would be a good thing. that V6 is rather underpowered for just the load of the truck itself, and having such a low gearing, while helping his top end, round town and launching performance suffers greatly. he doesnt have a 1000hp diesel under the hood where having 3.54's is needed to keep wheel spin to a minimum, his little v6 needs all the help it can get so going to 3.92's or even 4.10's would mean the engine will work less to achieve the same results. I know he has probably tossed around the idea of 4.56's. . .too much gear, even for the hemi's thats alot a gear. around town yea, you'll be roasting the tires light to light, but long mileage highway use will suffer. and for the same reason is why having 4.10's stuffed in the axels of my truck is too much. But it sure is fun when I ask my skinny pedal to tell the engine to belch out nearly 400hp

 

http://www.dieselpowermag.com/featur...ram/index.html

http://www.dieselpowermag.com/featur.../photo_08.html

I can only assume, and I am not an engineer, that if you have that much power, gears are not a problem. This guy can have 3.21 and still fly with a 1500 hp engine.


EDIT
YOU BEAT ME DREW.