I have a 2005 4120 with about 500 hours on it that I bought new. The starter began acting up after it was about (3) years old. It always started but sometimes with great difficulty. Usually I had to hold the key over for a while to get it to go. This spring it wouldnt crank at all so I pulled the starter and bench tested it with jumper cables and verified it was shot. I think the problem was caused by corrosion inside the factory-installed Bosch starter unit. Rather than get that starter rebuilt, or pay JD $300 for a replacement, I found an aftermarket (Powerstrike) at Amazon for a little over $100. The tractor has been starting great ever since I put that in. I noticed that JD is no longer using the original Bosch starter on the 40/20 series but has switched to a different part number. I got to assume that I wasnt the only one who had trouble with the old Bosch unit, especially since an aftermarket (Powerstrike) one was available at such a reasonable price. As of now, I havent heard of anyone else haveing trouble however. Other than the $108 I spent on that starter, the tractor has needed only (4) oil filters for scheduled changes. Overall it has been a great tractor with power to spare. I cant imagine why anyone would need or want more power in a machine of this frame-size, especially with the power-reverser transmission and open-station. I use mine, mainly on a 6-foot, light-duty bush-hog, and I can handle that, at a good clip, in just about any mowing conditions. I have loaded R1 tires and a 7 foot rear blade that will push mountains of snow uphill without loosing traction, without chains in the winter. If you are going to use it in the winter, I would recommend the block heater, which lets that Powertech engine start smoother at below zero temps than it does in mid-summer. Also, I would recommend the extendable lower-links if you plan on lots of implement changes as this tractor is heavy and hard to push around to make the connections without that feature. I paid $21.7K for mine with the 400X loader (that has been trouble free also and a great tool for pulling or pushing me out of the mud when I got in too deep). I have not been stuck in the 6 years I have had this tractor, my first 4x4, and it was something that I always did previously several times a year when all I had were 2wd's. I looked at the new ones at the county fair this year and it does look like some changes have been made. Lots of metal has been trimmed from the castings and the new ones must be significantly lighter as a result. That may save money in manufacturing but wont help with the traction force the tractors can develop. Hopefully the new starters will be a little more dependable at least.
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