99 dodge avenger gears will not engage

limited info generic answer can be a multitude of reasons --tranny + auto+ fluid low/dirty ---filter --torque converter-clutch pack--gear--tcm---standard +++fluid --clutch--linkage ++++engine--needs tune up --sensor[s]---++rear----failing--fluid----gear-----

Check the fluid in trans it might be bad could also be through out bearing

If the pedal is operating the clutch and its not a hydraulic problem then you do the mechanics trick of the trade ,warm up engine then turn it off ,now selsct first gear -handbrake off and start car in gear and drive with foot on clutch ,jerk the car a bit with the throttle and the clutch will release in the first hundred metres or so ,well they normally do anyway

My personal suggestion would be to go for these repair catalogs. I know this website www.reliable-store com
that i used to buy them from, and they have pdf online it was very good manual. Go ahead, I bet.

with engine shut OFF, try putting it in any gear. While leaving it in a gear, press the clutch all the way and turn the key to start ( do NOT hold key to start, but just for a moment). If the car jerks forward while starter is engaged, you have a clutch problem. If the engine turns over freely, you have a shifting linkage issue.

Possible causes are: The clutch is going out, the hydraulic clutch system is low on fluid, or the transmission input shaft is binding on the pilot bearing. 1. Is the pedal firm and does it feel like it used to? (low fluid). 2. Once in gear and moving push on clutch and notice when the transmission disengages. If it does not disengage until the pedal is almost at the top then the clutch is getting thin and will need replacing. 3. With vehicle on a smooth flat surface, depress clutch and try to shift into any and all gears. Notice if vehicle tries to lurch forward as shifter goes into gear. This may be a subtle lurch but should be noticeable. This checks for a binding pilot bushing. Let me know what you find. Thanks and please rate.

That burnt smell is what used to be your clutch disk, and you will need to replace the clutch before you will be able to drive that vehicle again. You should purchase a complete clutch kit for your vehicle, and it should come with a new pressure plate, clutch disk, throw-out/release bearing, a pilot bearing, and a clutch disk alignment tool, and be sure that the pilot bearing is replaced when that new clutch is installed.

clutch needing replaced, very common on all manuals

pedal travel adjustment,yes
gear shift adjustment,no

how much clutch pedal do you have when the car is running does the pedal feel loose? if the clutch is not disengaging when depressed it is most likely time for a new clutch

Your slave cylinder for the clutch is leaking. It's on the bottom of the transmission towards the engine (follow the fluid trail!). Though it's not too difficult to replace, it IS messy. And be careful with what you touch when you have that fluid everywhere, it eats paint. Usually a new slave will come with detailed instructions on how to properly install and bleed it.
Good luck!