First the particulars: I have a brand new 4×4 rancher. I got it about 5 months ago from a dealer and it currently has 35 hours / 307 miles on it. All of my riding has been on dirt roads mostly pleasure riding. It has not been abused at all, and is garage kept. It is the 2015 Rancher TRX420FM1. The base 4×4 model, with camo paint scheme. Ive not modified anything.
Now my problem: I was riding the other day down a dirt road, just cruising in 4th gear when I looked down and noticed the speedometer was wrong. It was showing my speed about 10mph too slow. I slowed to a stop and began testing each gear, and just watching the speed, trying to figure out what could be going on. I noticed that the speed would read accurately at certain engine RPM’s and then it would just drop several MPH on the speedometer even as I am still accelerating. I came home and began researching where the speed sensor was, because that was the first thing I wanted to check. I finally found where it was located, so I simply unplugged it for a minute then plugged it back in. I took it out back into my horse pasture to test it and it appeared to be fixed after doing this. Speed seems accurate in 1st, 2nd, and 3rd gear, but as soon as you get around 20mph/4th gear it seems to start acting up again. In 5th gear, when I open it up wide open I would expect the speed to top out at 53mph, but the speedometer will read well below that, not even 40mph.
I finally decided to take the screw out of the sensor and pull it competely out to look at it. It had a little engine oil on it but otherwise it looked fine. I cleaned the plug contacts, and then traced the wire and cleaned every plug contact when I came to a plug. I put it all back together and am still having the same problem. Im at a loss. The 4 wheeler seems to run completely normally – I notice nothing else that would suggest any other problem. The speedometer seems to be accurate up to about 20/22 mph when you go into 4th gear, and then its like 8-12mph low from then on. This is of course throwing my odometer and trip meter’s off.
The only thing I worry about is that Just before I went on the ride and noticed the problem, I moved some Hay with the 4 wheeler into my horse pen. It is a round bale, and the way I move it is by pulling it on a pallet which Ive turned into a sort of sled by screwing poly tubing all along the underside. The bale weights likely somewhere between 600 and 1000lbs. I have a 2" ball on the rancher and I just loop the high tensile wire around the ball and pull it into the pen. Its less than 100 foot it has to pull, but this does put a lot of stress on the 4 wheeler. I use 4 wheel drive for the pull. My pallet dug in just as I entered the horse pen and the 4 wheeler just began spinning tires and bounced a little trying to pull it. I immediately stopped and left it there. Ive moved hay like this once before and didnt have any issue. I am aware this likely exceeds the weight limit on the rear axle, and this shouldnt, in my mind, have any thing at all to do with the speedometer messing up. Ive decided not to move hay like this again to be safe. After I moved the hay is when I decided to just ride down the road a little as the sun was setting. Thats when I noticed the problem.
Ive went online to try and find an OEM speed sensor replacement but have had no luck, and Ive searched probably a dozen parts sites at this point.
Any info would be greatly appreciated. Sorry for the long post, I wanted to detail as much as I could here.
