Some tutorials are a little inaccurate, so there are times that you have to learn on your own.

Instead of naming the doors as: c_gear_door_l, etc., use these tag instead:

c_gear_top_XX [where XX is a number]

l_gear_top_XX

r_gear_top_XX

the reason I use XX is because there will be parts that will have the same tag. Especially the gears.

The gears themselves, for extend-retract, will just be tagged as:

c_gear_top
l_gear_top
r_gear_top

These are the parts that will be used to show the Extend-Retract animation.

Just make sure the key frame are within the 0-100 range.

For gear compressions, use these tags:

c_gear_bottom
l_gear_bottom
r_gear_bottom

If you need to use the same tag over and over again, make sure the ending numbers have an underscroll ( _ )before them.

Examples:

c_gear_top_01 -----not----- c_gear_top01

This is true for various other tags.

For rolling wheels, use JUST these two tags:

c_tire_still
c_tire_blurred
c_tire_still_XX [where XX is a number]. This is for four-wheeled aircraft.
l_tire_still

etc.

You don't need key-framing. Just make sure the X-Axis of the wheels are lined up with the world axis shown in the lower-right corners of the viewports.

I tried using tags like c_tire_slow [with or without key-framing], but the simulator renders it wierd or doesn't render it. I learned this the hard way when I made the Mercedes.

Yep!Doors started working unexpectedly-by the way without any change in names or something-I just reloaded sim...

Now...
There is no extension animation and gears are named exactly as you said-top,bottom,etc...

And may be it's not animation problem...because indicator in cockpit dazn show extension...By the way-is gear position indication depends on real gear position...I mean indicator shows "down" if only extension animation is performed correctly?
Hm-m,I dont think so because even there is no animation on gear indicator shows retraction and extension anyway,u understand what I mean...am I right...?

Ok.I checked it and found that gear animation is OK,what happens is that gear daznt extends if speed is above 60 ,as speed srarts dropping below 60 extension is starting...Look like cfg file twiking needed...

But what is the parameter controlling this?

Contact points?...
Hmm...
I know what each contact point do,but...wich one is responsible for gear extension speed?
Ok there is one that named "damage threshold" that defines what is the speed that gear is damaged,but this param is set to 1200-like Learjet's one...dont think this param controls gear extension speed,because my gear extends at exactly 60 wich is even below stall speed...

The damage threshold is the impact speed in ft per second that the gear gets damaged at, when you touch down.

feet per second?!No it's measured in feet per minute according to SDK-by the something strange with this value-for exaple-this param for Boeing is about 1200fpm-it's about 24 km/h-what is wrong?gear's damage speed is 24km/h?!Assuming that it may be really feet per second it'is about 1400 km/h - isn't it too much?

Sterk the gear ext,ret, is adjusted by the last 2 numbers in the cfg. file in the contact points in each wheel line.example=point.0=1, -9.583333, 0.0, -7.40, 32768.90, 1.0, 0.596, 0.0, 0.7, 2.5000, 0.80, 4.0, 5.0, 0.0, /\example=300.0(  Airspeed limit for retraction (KIAS),example=300.0 (Airspeed that gear gets damage at (KIAS).Hope this helps.  aceronzo

Glad I could help