Good morning, and welcome to the forum. Your initial diagnoses was correct, the clicking sound is from the e-unit or reverse unit, in the tender, at least that's working.About the wheels, not sure what you're talking about. The easiest way to confirm a problem is to remove the shells from the tender and loco, a very easy process and you can't get into any trouble. Once removed, spray some CRC tuner/cleaner on the motor and e-unit and let it dry. Don't get any cleaner on the knuckle coupler, it will eat it up. There is a CRC plastic safe spray cleaner, but it's flammable, I use the non-flammable version. After squirting the cleaner in both spots, let it dry. Place the loco/tender on the tracks and give it some power. The tuner/cleaner should have awakened the units, and it should run. That being said, it's time for a rebuild, all parts that are needed are available through Jeff Kane at the Train Tender..Bear in mind, ALL the parts dealers are about 2-3 weeks behind in getting your parts to you.The brushes you need are part #PA 9603, and while you're there, get replacement brush springs, part #PA10757-A. The brushes are the shouldered type, and the springs are the coiled type.This will get you started on getting your loco running. If it still doesn't run, we can walk you through a more extensive procedure to get you running. The 303 is a direct-wired engine/tender combo. It has smoke, head-light, and choo choo, and the best part is that it comes with pul-mor tires, giving you great traction. These tires are also available on ebay. I can send you the sellers name. He's been very good to me, and I do recommend him..If all else fails, send it to me and I'll do the work for you, no charge, only parts cost and shipping both ways..I have all the parts on hand needed to get this great little loco going for you. If you want to do it yourself, all of us here on the forum will be glad to help you. After 5 posts, you are allowed to post pictures which are a great help to us. Hope I helped..and welcome to the forum...Loren