I don’t own the Nytro anymore, but about a year ago I had to replace a rear shock and took some pics of how to do it.
Start by removing the bolts on one side. The skid will be removed with the sled on it’s side, so remove the bolts from the side that will be down. Ideally you want enough room on either side of the sled to turn the sled on it’s side.
Turn the sled on it’s side. I usually put something under the handlebar of the Nytro.
Remove the two bolts from the opposite side, and remove the skid. It will be a little easier to remove and reinstall the skid if you take the tension off the track adjuster, but it’s not a necessity.
Put the skid on the bench and do the work.
Re-installation is just the reverse. Put the skid in the track, and line up the front cross shaft with the hole. Put some blue lock-tite on the bolt, and start it by hand. Use hand tools or low powered air to drive it in, but don’t worry about tightening it all the way, that will be the last step.
With the front bolt in, line up the rear shaft, and insert the bolt by hand. I usually use a pry bar and my knee to line it up, but it doesn’t take much pushing.
Flip the sled over on the other side and repeat. Put in the front bolt first, then the rear. Depending on your sled, you might have to make sure the skid is not holding the weight of the sled by putting a block under the bumper.
Tighten the two bolts on that side with the impact wrench.
Stand the sled back up and tighten up the other side as well. Check track tension and alignment and you’re done!