I have a tendency to shift from nuetral into gear while I'm rolling in the intended direction, one would think that this would aid in easing the transmission into gear since you are rolling that way anyway.  Could this actually be potentially damaging, i.e., should you always only shift into gear while at a stop, or does this make sense?

e.g.  having backed into a parking lot on a slight incline, you disengage the parking brake, shift into nuetral, and begin to roll forward.  As roll forward out of the parking spot to drive off, you shift out of nuetral into drive.

i agree with striker.  with an automatic transmission its a bad idea.

with a standard transmission its not a big deal IMO

Shouldn't hurt a thing, but, you can put me in the "no expert here" category.
I really can't think of a reason that it would damage anything though.

What are some of the other things you worry about?  Say, do you worry about how teflon sticks to the pan?  




 

If you have the auto in N and are rolling backward at a low speed <3mph and shift into R it will not impact the trans in a negative way.

If you are traveling 65<mph pull the trans into N and then move it back to D in will not negatively impact the trans.

If you are moving and forward or rev and move the trans into P you could snap the parking paw off and that would impact the trans in a negitive way.

The biggest problem with moving the trans in and out of gear is not the trans it is the shock in the drive line from the trnas to the wheels axles,u joints, rear edns etc......

I have NEVER taken apart any american made autotrnas but I have done more than a few german and Jap auto makers products.

Quoted: If you have the auto in N and are rolling backward at a low speed <3mph and shift into R it will not impact the trans in a negative way. If you are traveling 65<mph pull the trans into N and then move it back to D in will not negatively impact the trans. If you are moving and forward or rev and move the trans into P you could snap the parking paw off and that would impact the trans in a negitive way. The biggest problem with moving the trans in and out of gear is not the trans it is the shock in the drive line from the trnas to the wheels axles,u joints, rear edns etc...... I have NEVER taken apart any american made autotrnas but I have done more than a few german and Jap auto makers products.

I agree.  Chances are the weakest link will break first.  IE: u-joints, diff. gears, ect.
 

At speed is if you are going fast enough that would cause the car to go into O/D or whatever gear/s causes the vehicle to lock the torque/stall converter. (Recent vhicles the converter is controlled by the computer, earlier vehicles could have been a combunation of both computer or transmission controlling lockup.)

Lockup simply measn the converter doesn't exist. A normal converter will have some slip to it at all times. There is a loss of torque on what comes out compared to what goes in. This is a loss in torque. Generally a small percentage on a stock converter. Like 2-3% maybe.  

When the converter is locked this may cause a shock to the front of the transmission and possibly  the rest of the drivetrain. The input shafts are allot stronger now than they used to be so unless this is a Ford product with an AOD you should be ok.

There is also a small amount of clutch pack or band wear that could happen if the valve body reponds slowly when increasing line pressures after the transmission is re-engaged.

I think it really depends on what you feal when the transmission is re-engaged. Herking and jerking bad. So smooth you can't  tell is probably ok, but there is still that risk of clutch wear.

I tried it going down a hill at 55 MPH with the SUV to try and save on some fuel, the transmission goes into OD then into 4th then back into OD. (Explorer with a 5 spd auto.) That was enough for me.

I instantly remembered replacing AOD after AOD in my Mustang for years. That was enough for me.

Any difference in wheel speed to engine speed will be made up in the touque converter.
you would have to be really moving to hurt anything.  Nothin to worry about.  Now a neutral drop
will definatly have an adverse affect on the torque converter!

Driveline shock.................................................

If the tranny stays in gear the driveline stays "in tension". If you drop it to neutral and there is no tension on the driveline, when you put it in gear, say when stopped, the first thing that happens is the tranny starts to spin the driveshaft, which put the u-joints back into tension............... along with the output shaft, and the rear end gears.