The 4005 tractor is the latest offering in a long-line of JD CUT tractors beginning with the 1050, 1070, 990 tractors.
Basic, no-frills machine.
Long-lived, sturdy, dependable, very fuel efficient and many of them are still doing what they were designed to do after 30 years.
Very few problems that I've seen discussed here on TBN over the years. I owned a JD 970 TLB for just over 4 years and it was a great machine.
The single, most often heard complaint regarding these tractors has been the 2-stage clutch and having the clutch "stick" to the flywheel after the tractor has sat unused for a length of time. Film of rust will form on the clutch plate and the flywheel and the plate won't release. If left for an extended period of time and with a local environment that is warm, humid, etc. chunks of the clutch plate can break off when it does finally free up.
However, this is not a frequent occurrance and can be avoided entirely if you block the clutch pedal to the tractor floor with a piece of 2"x4".
AKfish