John Deere does not bolt the back wheels on like Kubota,Kubota has the stud that goes through the hub and has a nut and a lockwasher on the backside.
The John Deere 4000/4010 series the bolts just screw into the hub and do not go through the back side,thus they are not able to put a nut and lockwasher on the inside of the hub.
I had a loose wheel bolt problem a couple years back.
My 1st winter of ownership I had R-4 tires and was using the backblade to do some major dirt removal,the R-4 tires had a fair amount of slippage,no loose wheel bolt problems at all.
The next summer I bought new R-1 tires and rims and installed them my self.The R-4 tires did not offer the amount of traction I needed.
Later on the tractor goes back to the dealer to have a small hydro leak repaired that was caused by the dealer who had worked on my tractor earlier.
Late fall I continue working on my landscaping project that I had started the previous winter,the only difference is this year I have R-1 tires and rims where as the previous year I had R-4 tires.
Before I know it the wheel bolts are starting to loosen on the tractor,I have to torque them frequently,because they keep wanting to back out.
The tractor goes back to the dealer to have a 4 in 1 loader installed,I tell them about the loose wheel bolt problem.
The dealer calls me back and says the axles and wheel centers need replaced,the bolt holes are damaged.I say okay..........they tell me John Deere is not going to cover the expense because I installed the R-1 tires myself,I tell them to tell John Deere that they were the last ones to install the wheels because the dealer had them off to fix the hydraulic leak.
They get back with me and John Deere has agreed to install new wheel centers and axle and hubs.
The tractor is delivered to my home with the new loader and wheel centers,I go back to work on my excavating project which requires lots of heavy cutting the soil with the backblade and about 2 HOURS ,that is right 2 hours the same day the tractor is returned from the dealer the wheel bolts are coming loose again.I call the dealer and they do not know what to say or do,the John Deere rep more or less washed his hands of this ordeal.I am on my own. I finished up with my project and have not had anymore problems.
Here is my hypothesis:
1. The 1st winter doing this excavating work the R-4 tires slipped more than the R-1 tires do thus reducing the amount of torque transferred to the axle bolts and wheel centers.
2. The second year doing the same job the R-1 tires offered me so much more traction and able to move larger amount of dirt with the blade,the wheel bolts were getting a lot more torque than with the R-4 tires.
3. I feel that if the rear wheels had been designed to bolt on and have a nut and lock washer on the backside like the Kubotas this problem would not occur.
I have not had any problems just mowing and tilling,general tractor work.But anytime I have the backblade on the tractor and I am moving lots of dirt,heavy pulling with blade is when I experience the wheel bolts coming loose.
The project I was doing was asking a lot out of the tractor,people who came to my house thought I had been using a bulldozer for the amount of dirt I had moved.
I put the tractor to the extreme test and found the flaw.
One more note, the dealer that done the repair work was in Ohio and is not the dealer in WVa(my favorite dealer) I originally bought the tractor from.
I have the old axles and wheel centers and I will be darned if I can see anything wrong with them.