I inserted tire tool into the guide tube and turned it but the tire would not winch down. Used a flash light, and saw that the guide tube that connects to the hoist mechanism was detached. I was able to lower spare tire using two long 1/2 inch drive extensions. I need to know what part I need to repair the guide tube. I appears that a part is missing where the guide tube attaches to the stud that turns the winch mechanism, but I'm not sure. Definitely not designed very well.

try one that has the same or better end also try lifting tire up while turning and you can lower in down and lubercate it with spray lube and try again

insert the winch rod and wind it down. There is a clutch lock incorporated in the winch and it will take some effort to release it but basically just wind it down.

I had the same issue on my 2006 pathfinder and found this solution to be incorrect. It is not the secondary lock. There is a piece of plastic tubing that guides the rod down towards the lowering winch, however it doesn't go all the way to it. The rod has become wedged between the lowering winch and this piece of plastic. You can get it free but it will take patience and some twisting and pulling. Once you do get it free try again to drop the tire and when you succeed cut back the plastic tubing so this doesn't happen again.

under the rear seat should be a tool kit with the handle for the jack pull these out and goto the back of the truck ... over the licence plate but under the tail gate is i hole ... use a flash light to look in the hole ... match the rod that is in the kit to hook up to the lower winch for the tire and lower the tire down

that's going to be a dealer item unless you call around to the junk yards and hope fully they
might have one laying around

hope this helps you
bob

There is a compartment inside the rear hatch (sometimes on the driver's side and sometimes on the Passenger side) that you can open and your tire changing equipment and instructions will be in there. (unless someone removed it) The jack handle must be used to "crank" the winch to let down the cable that holds the spare tire in place.

Hello! Here is procedure to remove spare tire...Guru...saailer

1. Park on a level surface and put on the emergency brake. If the car is near the side of a road, switch on the hazard lights.
   
2. Locate the tire repair kit. It consists of a jack, a jack rod and a wheel nut wrench. In the regular cab, pull the entire seat bench forward. The tools are located behind the drivers seat. The King cab model has a tool case located directly behind the driver's seat. The Crew cab stows the tools behind the back bench. Pull the bench forward and remove the tools.
   
3. Insert the square end of the jack rod into the square hole in the nut wrench. This gives the jack rod a handle.
   
4. Find an oval shaped hole in the back of the truck under the middle of the tailgate. Look through the hole and find the winch for the spare tire. It is a circle with two notches.
   
5. Insert the T-shaped end of the jack rod into the hole. Slip the T-shape into the double notched circle of the winch.
   
6. Turn the jack rod counterclockwise to lower the spare tire to the ground.
   
7. When the tire is completely lowered to the ground, remove the center retainer chain and pull the tire out from under the truck.
   
8. Wind the jack rod clockwise to completely retract the retainer chain
   

I’m happy to help further over the phone at https://www.6ya.com/expert/david_6df67de3b14de867

I got his post from Wiki Answers:

The winch is probably broken and will need to be replaced. You can use a cut-off tool or an hand held angle grinder to cut the cable holding the tire up, then you will have access to the tire and can replace the winch.

Wear safety glasses when operating any cutting or grinding equipment.

Common problem for these trucks is that the tire is pressing up against the tube that you slide in the handle thru. It wont connect to the gearing tool to allow you do drop the tire down. The only way I found to get around this was to rip out the tube from underneath. Then try the handle again.
Happened in all 4 of my trucks, let some air out of the tire, it'll relieve the pressure on the tube so the gears mesh.

I had the same problem and the shop I took it to couldn't get it off either. But I opted for them not to cut it off and I took the truck home to diagnose what the problem was. So to make this short, I got the spare down and the only way you can do the same is by using a flat head screw driver, pliers, and some "Deep Creep" penetrating oil. 
First: if you have the tire down the standard 2" or so, take your pliers and pull at the base of the cable "downwards". (the cable should free from the bracket under the tire that holds it up).
-Then spray penetrating oil around the bracket as this is what is causing it not to release. In the manual it suggests pushing it back up with the jack until it clicks to allow it to come down. Most likely this will not work as dirt and corrosion will freeze the mechanism that acts as the secondary lock. 
-Take your jack and lift up your spare, holding the weight on the rim and not the bracket attached to the winch. This should free up the winch to allow movement. Then taking your flat head screw driver and you will likely need a flash light, look up into the hole where the cable comes from. You will see there are two little teeth attached to it inside holding it to the frame of the winch. First try prying the teeth away from the lip of the hole to allow the bracket to drop. If this doesn't work, then stick your flat head in between the sides of the arm attached to the teeth and pry outwards, allowing the arm to free up enough to allow movement.
This should drop your tire down and avoid the expense of buying another winch after cutting yours. 
Good luck!

Have someone pry down on the tire while turning...