I've heard this a few times is it true that the automatics have a higher overdrive ratio than the 6spds?
If so do the autos loose so much in the loose torque converter getting to lock up, that unless you almost only drive on the highway you loose the MPG gains?
Which auto is higher geared and which years had it?

 

i just picked up my 6spd on last tues and let me tell you there is a big (make that huge) difference. I also have an auto that i bought in dec at 60mph the auto runs at about 1650 rpms in o/d, the 6spd is at 1900 and its feels like it has a good 75hp more than the auto

 

06er
So what is the real difference in power in your two trucks? Is it that one just happens to run better? Or is it the transmission. When you say it has so much more power it that loaded or empty? Flat or hill climbing? Is it because with the manual when you put your foot in it the power goes to the tires and with the auto it down shifts and you loose the power in the torque convertor?

 

i got an 03 with a 6 spd and i think it has more jam that the auto our buddy has in his 05. but maybe thats just me. i also like mine when towing, that think just goes and goes and goes. it pulls 15000 lbs like nothing there with no boxes on at all

 

All autos have a .69 overdrive and the G56 6 speed has a .79 overdrive. With 3.73s the auto will turn 2000 rpm and 73 mph, the G56 2000 rpm and 64 mph. At 2500 rpm and auto does 91 mph, the G56 6 speed does 80 mph. All speeds with 265 tires.

 

Skydivers numbers dont apply to those with the NV5600 manuals. NV5600 were geared a lot higher than the G-56's. I believe the G-56's were available on the 05 and up Rams.

Nav

 

havent pulled anything with the 6spd yet only have 600 miles on it. I just think its all in the transmission. both stock both empty as much as i hate shifting i'm in love with the 6spd

 

NV5600 6 Speed manual transmissions have a .73 overdrive. A 3.73 geared vehicle's speed would be 69 mph at 2000 rpm and 86 mph at 2500 rpm. I have all this data in a spreadsheet if anyone would like it. Got it from a very knowledgable guy (Klenger) over on RV.net.

 

RPM=
MPH x trany gear ratio x t-case gear ratio x rear end ratio x 336
actual loaded diameter tire size

 

If the six speed is running at 250 more rpm it probably is making 75 more hp...unless you mean the six speed feels 75 more hp at the same rpm?
Much closer to peak hp at 1900 rpm than 1650.

I do prefer the auto...but I don't tow often or heavy...and I am in heavy traffic lots.

 

You would think the Auto's would see a little better mpg on hwy. .69 vs .73 nv5600, vs .79 G56? Maybe the autos loose so much fuel getting going that is doesn't show up in the end. What about coasting is a auto useing more fuel just by what little drag it puts on the motor. What about putting a auto in neutral while going down a big hill and back in drive while going 60mph?

 

A little after the 1/2 way point of the 05 model year they started with the G56. The date on my engine is 1/11 and the date on the door jamb, for the trucks build date, is 1/05. Since they stopped production early, I don't think there are that many 05 G56's. I started looking in March 05, bought in May, and couldn't find one to test drive.