New Purchase - JD 3720 vs 4120

jimccraig · Jan 14, 2007

I have been researching for some time for a first time tractor purchase. Own 37 acres in TN; about 20-22ac open fields. My research has led me to either the JD 3720 or 4120. I am not sure which model would be best. I thought the 4120 was the choice but wonder if that might too big or heavy for finish mowing. Would R4's tear up a yard too much?

Two quotes so far on the 4120, 400X loader, MX5 cutter:

John Deere.com lists at $31,800
Dealer 1: $26,800
Dealer 2: $26,960

One quote so far on the 3720, MidPTO, 300x loader, MX5 cutter
Deere.com lists at $31,000
Dealer 1: $25,500

Any help or advice would be appreciated.

Kyle_in_Tex · Jan 14, 2007

Although the 3720 is an awesome workhorse in a small package, the machine that you would shred 20-22 acres with is not the same machine you'd want to cut your front lawn.

The 4120 gives a bit bigger footprint with bigger tires with just a small increase in turning radius. The bigger tires will ride smoother over the bumps. If you don't add liquid to the tires, the R4's won't hurt a lawn if the soil is relatively dry. You might even look at the MX 6 if you get the 4120. I cut about 22 of our 25 acres. (Roughly the same as you) Luckily, I have the use of my FIL's 5420 and a 6' Bushhog. Yes, I have cut it with my 4310 and a 5' cutter, but when it bogs down on power cutting thick Bahia grass, it sure is frustrating. (It can bog down the 5420 too). Not to mention taking much longer. I can cut up to 4 acres an hour with the 4310 but only on open fields that have been cut recently. Plan on a full day to cut 20 acres. Especially with a 5' cutter.

Good luck on your search and your prices look competitive.

Zinno87 · Jan 14, 2007

4120......no questions asked. I purchased a 4320 a couple of months ago and am so glad that I went for the 4000 series rather than the 3000 series. It sounds like you have a lot of property and I think that the extra weight and size of the 4120 will really help you out.

Kahuna · Jan 14, 2007

I bought a new 3320 this fall with the e-hydro, cx loader, heavy duty bucket R4 tires, I-match with a few other options and paid $18,900. I looked at both a 3720 and 4520 but the 3320 fit my needs. The only difference beween a 3320 and 3720 is a turbo, turned up pump and a little larger radiator.

I have a 65 hp farm tractor for the heavy mowing with a MX6 mower. I can cut pretty thick grass and weeds at about 4.5 mph. A MX6 should run you about $2100, a MX5 should be a couple hundred cheaper. The 3320 will pull a MX6 also but I have to go a little slower and go through shorter grass.

There is hardly any price difference between the 3720 and 4320. I would go with the heavier frame 4xxx series due to the size of your operation. One thing to keep in mind though, the 3xxx series is really versatile with the loader, you can get into places the 4xxx wouldn't even think of. However, if mowing a large area is your goal, I think bigger is better. I personally thought paying an extra $3000 for the turbo on a 3720 was absolutly ridiculous. You can buy a replacement turbo on a 180 hp farm tractor for about $800, you know JD is really sticking it to you for those few extra horses on their compacts.

If you are going to cut all that grass (and money is not a concern) you may think about a cab. I considered it but couldn't get past the $5000 plus price tag. The $100 umbrella sounds like a better deal to me, however, that air conditioning sure would be nice on a hot humid day, not to even mention swatting the mosquitos.

jcmseven · Jan 14, 2007

Jim,

I have had both a 3000 and 4000 series tractor. In fact I have owned three mid-frames, two of which have been 3720's. This is what I have now. As far as which one is better, I think with the size of your property the larger machine is your better choice. You will not be able to duplicate the power-weight of the 3720 with the 4120, but it will do a great job. The large frame 4000 series do ride a little better over rough bumps. Fuel consumption is higher but not by that much. The 3720 would do fine also, though. They are seemingly a little harder to find, as they are the top of the 3000 series, where the 4120 as the entry level 4000 series machine, is more ubiquitous. Neither machine would damage grass with R4 tires, even loaded. The 3000 series is by far more manuverable and somewhat easier to see around for sure, but the 4000 series machines are pretty agile for their size, just not as agile as the 3720 would be. So, open fields favor the larger machine, tight spaces (such as my property) favor the smaller machine. I would probably still have my 4520 if I could have fit it into the spaces I needed. I could not access about 20% of my property due to its dimensions, so for me a mid frame was actually MORE versatile.

John M

gamble77 · Jan 15, 2007

Jim sent you a PM

jimccraig · Jan 16, 2007

Thanks for the feedback so far; it is really nice to hear comments from people who have been actively using a particular model.

Anyone know of issues with the 4120 pulling the MX6 cutter from a size standpoint? I imagine the loader balances the tractor fairly well with the cutter.

Also, anyone seeing the need for a ballast box when using the loader with the 4120?

Thanks again for the advice.

HappyCPE · Jan 16, 2007

Jim, my 4320 pulls a 6' brush cutter of questionable heritage without a problem.

As for the ballast box, you will absolutely need something. I bought the JD box, put casters on it and filled it with concrete, and it weighs +/- 820 lbs. It does the trick. On the other hand I have a grapple, HD bucket w/ teeth and that puts a lot of weight on the front end too, so a counterweight is an absolute.

braque1 · Jan 16, 2007

Jim

I also had the same dilemma when upgrading from my JD 4400. It was a difficult decision to choose between the 3720 and the 4120. I ultimately chose the 4120 and I'm very happy with my decision. At the time I was concerned with the larger frame, but have not found any problems. It has proven to be much more stable than my 4400 which is similiar in size to the 3720.

I use a MX6 without a ballast box. I have found the loaded rear tires and the front bucket have been sufficient for balance.

Good luck with your decision. They are both good tractors.

jimccraig · Jan 26, 2008

Just wanted to say thanks for all the info from everyone and all the informative posts; pulled the trigger on the 4120 last March and have been extremely pleased with it so far. Glad I went with the bigger machine versus the 3720. See the attached photo. Thanks again!

4720 OWNER · Jan 27, 2008

4720 with cab. Your tractor with turbo, tons of power and the Loadmatch is so cool. Ran some open station, ran some with cab, definitely like the idea of a cab. Your rear tires look rounder than mine, what air pressure do you run? I usually run just enough to get the outer part of the lugs off the concrete a little, and that changes with whatever is hanging off the 3 pt. I have heard others say this model is a little loud, with the cab i can take a phone call and keep plugging away. Of course the calls are short when they are interfering with my seat time!!

By the way, congrats.

jimccraig · Jan 28, 2008

That photo was taken after the unit rolled off the trailer from delivery. They had the tire pressure real high for some reason. Same thing when i looked at units on the lot.

The noise is not too bad; I can field a phone call if I throw the throttle all the way down to talk. Couldn't keep cutting at all. Would have liked the cab but had to make some price cuts somewhere plus I have lots of trees and need the clearance. My place is really level so sometimes I leave the ROPS down to get more room; but then it gets in the way of the 3-pt hitch raising up.

wolc123 · Jan 28, 2008

It will not get in the way of the 3 pt if you pull the pins out and put them in the lower position before you lower the upper section. The upper section will stick out at a greater angle allowing the 3-pt to be raised all the way without contact.

RollTideRam · Jan 28, 2008

wolc123 said:
It will not get in the way of the 3 pt if you pull the pins out and put them in the lower position before you lower the upper section. The upper section will stick out at a greater angle allowing the 3-pt to be raised all the way without contact.

I gave that same advice to someone looking for a new rops on a 2520, but your wording is alot better than mine was. He never posted back to say if he tried it. It took me getting my lx5 hung in the air to figure it out. JC

jimccraig · Jan 29, 2008

It does not need to much space now but if I really want to raise the cutter almost all the way up, it hits that bar. I will give it a try this weekend and post back.

ddivinia · Jan 30, 2008

jimccraig said:
Thanks for the feedback so far; it is really nice to hear comments from people who have been actively using a particular model.

Anyone know of issues with the 4120 pulling the MX6 cutter from a size standpoint? I imagine the loader balances the tractor fairly well with the cutter.

Also, anyone seeing the need for a ballast box when using the loader with the 4120?

Thanks again for the advice.

A buddy of mine has a 4120 and MX6. It works fine. I have a MX6 on my 4720 - works fine. If you are cutting really thick stuff you might have to slow down some, but I can bog my 4720 in REALLy nasty stuff also.

D.

ddivinia · Jan 30, 2008

jimccraig said:
That photo was taken after the unit rolled off the trailer from delivery. They had the tire pressure real high for some reason. Same thing when i looked at units on the lot.

The noise is not too bad; I can field a phone call if I throw the throttle all the way down to talk. Couldn't keep cutting at all. Would have liked the cab but had to make some price cuts somewhere plus I have lots of trees and need the clearance. My place is really level so sometimes I leave the ROPS down to get more room; but then it gets in the way of the 3-pt hitch raising up.

I wear headphones when I run my 4720 - it will cause hearing damage for sure.

Not having a cab can be a plus. I have the 5525 cab for the bigger stuff and the 4720 open station just works better for close in with e-hydro and less stuff to tear up. The cover on my 4720 is pretty ugly no days - I might just take it off, but it give the tractor character.

D.

Mike5252 · Jan 31, 2008

Rolltide, you were "spot on" with your idea to rest the ROPS on top of the pins as opposed to putting the pins thru the holes. I tried it this weekend and gave me just enough room where my snow blower would not interfere w/ the ROPS.

Mike