Which one has more PULL?

[Rcpilotlv]

Dont want to start a argument here i would just like to have the facts. All else being equal here (gear ratio,weight) which transmission pulls a load better manual or automatic. I was always told that the manual will but i do not have any mechanical knowledge as to WHY? Not trying to say ones better then the other as you can see I own a auto now but will be trading it in shortly for my new truck. . By the way i have never had any problems with my auto... Just want to know WHY?

 

[work2muchplay2little]

I think considering just the physics of the two transmissions that the manual will deliver more of the torque produced to the ground. That is until the auto's torque convertor is locked up which in essence produces the same "mechanically direct" connection with the engine as a manual. Until the torque convertor is locked up, the fluid coupling between the engine and transmission will cause greater power losses with an auto transmission. Manual's have some other advantages for towing; they have more gears to choose from, and can take advantage of an exhaust brake more readily (although auto's can be modified to do so). Drivability and personal preference are an entirely different subject. One more thing worth mentioning is that Bill Kondolay's valve body and torque convertor upgrades narrow the gap in efficiency for the autos considerably.

 

[Mundgyver]

I would think this would boil down to a matter of personal preference. I have a friend that has a 2500 quad 4x4 with an auto. He likes it cause it does the work and he just drives it. That's ok. Me I like shifting and feel that I have better control on the down hill. An auto gives you a nice steady pull when accelerating. Takes a little practice to get a good smooth shift with a manual, but thats the challenge. I think it not which one is better, but which one YOUR happy with. Auto does have an advantage for a person that has a handycap where a manual could present a problem. When my legs and lower back finally go out on me, then I will get an Auto and wonder why I did not buy one to begin with. Enjoy what every you drive.

 

[Archive]

Originally posted by Mundgyver

I would think this would boil down to a matter of personal preference. Enjoy what every you drive.

I agree completely!

 

[SLightfoot]

Manifold pressures....

Although the manual is better suited for heavy loads, since it is simply more durable, the auto does have one BIG advantage, that is, you don't lose your manifold pressure (boost pressure) between shifts like the manual does.



Believe me, when you are starting on a hill from a stop, this is a BIG advantage. Just losing that boost really cuts into the acceleration.



I wouldn't trade my manual for towing though.

I like to "pick" my gears more accurately.

Just wish I had the 6 speed.



My . 02



Shawn

 

[klenger]

Manual transmissions don't have coolers. Could that mean that they deliver more of the power to the rear wheels?

 

[Mundgyver]

You will always get more usuable power through a manual transmission. This is because of the nature of the mechanics. Everything is coupled together via motor/clutch/gear/driveline. An auto on the other hand has an inherant loss. Todays autos are much better that those of just 5 years ago. Where you lose out in an auto is the fluid. The torque converter is just that, a torque - converter. It achieves this by rotation of vanes kind of like those in the turbo, only with a different shape, that are inside of the converter housing. If you look at a cut away of a converter it has a look kind of like spiral. With this thing spinning around at what ever RPM the fluid is being pushed to the outside and around. There is some slippage as these vains slide the fluid. I do not know what the loss is in %. You use to figure around 30% a few years ago, but I know that newer autos are more efficient with the designs that are out there now. The valve bodies and their design also play a big part in this. With the manual tx you take out the fluid slip problem and then it is just a matter of mechanical coupling. That help.

 

[Strick-9]

Gear ratios

I need some help with the numbers here, but the auto has a much higher speeded overdrive gear.



All things being equal (ie. tires, rear end ratio, power), the manual would have a gearing advantage over the automatic during normal freeway (i. e. OD) pulling.



-Chris