My Kirby won't kick into gear.

No.
Theres a shaft on the motor to drive the roller, belt connected to it.
Electrical power drives the motor, which in turn will spin a Brush Roller.
Some vacuums may have an additional roller to a gear system to power self propel.
Others, like a Kirby, have a separate Geared 'Transmission'.

To place the kirby G4 into gear - out of Neutral - just press down with your foot, the Gray & Green lever that is labeled N on the left side of the lever, which is gray, and D on the Right side of the lever which is Green (probably for GO). It is located directly below the Power button.

Good Luck

See Pic...

If by "lever" you mean the step on rocker pedal at the rear of the unit, then we're talking about the same thing. If not, then I have no idea what lever would move to "D" or "I". When the pedal is depressed on one side it puts the drive mechanism into gear, when it's depressed the other side it moves the drive mechanism out of gear. It's about that simple, unless the pedal is broken inside the drive box, then nothing happens either way, usually. The only way to tell if it's really broken is to try it in both directions, if there's no drive in either side then there's a problem in the box. You'll need to take it to a qualified repair shop, not everyone can repair these drive boxes.

There is an adjustment for the transmission and it is wrong. It could also be worn. The Kirby has an amazing warranty. See if you can get it serviced for free.

the slide has shifted forward slightly, this happens when the kirby
is hit against walls and skirting boards. you will need a service by your local kirby engineer. see kirby.com for local agent

her2 was not self propelled

contact your local kirby agent for repair or kirby.com

Jon,
Here is a helpful link to use to adjust the tranny. About a 7 on the difficulty level.

http://www.greatvacs.com/Kirby%20Transmission%20Adj.shtml

Marci

There are few things that may have gone wrong:
First thing to check is if when pushing pedal it moves gears located on the rear axle (you will have to take cover shell off to see that)
If that works fine then primary belt may be broken (see it here). Then just replace entire set to make sure that belt type matches gears
Last - the most expensive problem - the main transmission belt within transmission is broken (then I would recommend replacing entire transmission)

No, you just need to take it to a shop for repair.