790 HP Reduction By John Deere

Golfgar4 · Oct 2, 2003

Dave,

Thanks for the info. Yours is the first reply that I've seen that really describes the abilities of the 790 so well. It sure sounds like a workhorse that can stand up to the demands put on it. It definitely will help me to rethink my decision.

Let's see....790 is less expensive, so could buy more implements, could probably get by with smaller trailer, will fit into smaller areas easier, etc.

Yeah, maybe rethinking needs serious consideration! /forums/images/graemlins/grin.gif

RobS · Oct 2, 2003

Garry, to further reinforce what Dave said about the 790, our local NationsRent used to have a 790 in their rental fleet. I'd say if it's good enough for rentals, it's good enough for just about anything.

I will also add though, that since they've teamed up with Lowes they now have a 4XXX sitting there occasionally. Full armor package and HST. I suspect the HST is big plus for the rental business /forums/images/graemlins/smile.gif

mountain_man · Oct 2, 2003

Smilingreen - Wow - what a terrific post /forums/images/graemlins/smile.gif I knew my 790 was good, I just didn't know how great it really was. Thanks for all the details. Now I need to get some more projects done...

Mrwurm · Oct 2, 2003

Garry, glad to see that you are finally narrowing your choices down to 8 or 9 models by 4 or 5 manufacturers. /forums/images/graemlins/tongue.gif

Golfgar4 · Oct 2, 2003

Have I got it down that far already?? /forums/images/graemlins/smirk.gif

Boy, if I keep it up at this pace, I'll be ready to buy..........

when I'm about 75!?!?!?! /forums/images/graemlins/crazy.gif

rdam · Oct 2, 2003

Obviously, the readers of this forum know of the engine change in the 790. However, some dealers/salesman do not. I happened to mention the change to a JD saleman in Daytona while looking at a JD5103. The man assured me that I was misinformed and assured me that the JD 790 was indeed a 30 HP machine.

I doubt Whiskey or F350Lawman were intentionally deceived. However, they may be able to eke out an implement (or a sunshade for Dave) to compensate for the reduction in HP. Especially if you have a sales contract which indicates a "30 HP model 790".

I think that's more than fair.

zuiko · Oct 2, 2003

I talked to one dealer when I was shopping around who tried to tell me the 990 wasn't a current tractor. Some of the guys out there seem to less knowledgable than others.

smilingreen · Oct 5, 2003

Rob,
Saw a brand new 990 sitting in my dealers shop this weekend. Very nice machine. Wish I had one!!! /forums/images/graemlins/frown.gif /forums/images/graemlins/frown.gif (along with my 790)
I got to talking to him about the 790 and 990 series versus the 4000 series. He told me he rarely sells a 4000 series because there are just more things that go wrong with them in the tranny, being that they are hydro versus manual. (his words guys, not mine!) There is a lot to be said about that. My local rental yard has a couple of 4400s, but in talking to them, he tells me most of his customers are not adept to driving a manual with a clutch, so he buys the hydro models as a preventative measure of burning out the clutch disk. If it were up to him, he would have the manual model.

Mark_D · Oct 5, 2003

I bought a 790 in April of this year w/the 419 loader. I too was disappointed to later find out that it was only 27hp instead of 30hp....my dealer did not know of the change and even after I bought mine the JD website still listed it as being 30hp. I thought of emailing JD for a partial refund, but I think it would be a waste of time. The main complaint I had of mine is that the lift capacity of the loader was very weak......I did a little tweaking on the hydraulic system relief pressure and now it's got some power!! It will now lift more than the weight of the tractor can handle, which is the way it should be. That's why they make heavy implements to put on the 3ph. To anyone else with a 790, I highly recommend turning up the relief pressure.

F350Lawman · Oct 5, 2003

To anyone else with a 790, I highly recommend turning up the relief pressure.

Alright I'll bite...how?

Whiskey · Oct 6, 2003

Mark_D

I'm right behind F350lawman.....how did ya do it?????

Whiskey

Mark_D · Oct 6, 2003

The rockshaft assembly has the relief valve in it for the entire hydraulic system. That means by increasing the relief pressure there, then you increase the lifting ability of both the three PH and the loader. There is a little cap under the seat that you remove and you add shims to increase the pressure. The shims come in an assorted package (about $2.50). I added two packages worth. The system is set at 2050 PSI from the factory. I'm not sure how much I've increased it by, because I haven't put a guage to it yet, but I don't think it was too much because the relief will not stall the engine at an idle. The loader will now pick the back end of the tractor off of the ground (with fluid in the rear tires). It is now comparable to my brother's New Holland 1720 tractor. Keep in mind that JD would probably void your warranty and there are obvious safety considerations in doing this, but in my opinion it was WELL worth it. I will post more later, including the part numbers for the shims and possibly a picture. It is a very easy modification that only takes about 5 minutes to do. My guess is that I have increased the relief pressure by about 200-300 PSI. That is still within the specs of all hydraulic cylinders that I know of. As stated, I will post more later.

Mrwurm · Oct 6, 2003

Mark D, thanks for being a renegade. I don't feel so lonely now. You are sure to hear some disparaging comments about this thread. /forums/images/graemlins/blush.gif I increased the relief pressure to my FEL on my NH by turning a little screw that is part of the valve.

F350Lawman · Oct 6, 2003

Thanks, I look foward to the pictures and part #s.

Mark_D · Oct 7, 2003

The part number for the shims is AM875169. I believe the is the number. There is another number on the package (20030213DY4), but I think the first one is the part number. You need to order two of these packages. It is an assorted pack of shims that you can put in to increase the relief pressure. I first used one package, but that didn't seem to increase it very much, so I used two full packages. This really did the trick. Before my loader was so weak that it wouldn't pick up a full bucket of sand. Now it is just right. I will attempt to get some pics to post on here soon.

cowboydoc · Oct 7, 2003

REally what you need to look at is pto hp. On bigger tractors they don't even post anything but pto hp. If you only went from 25 to 24 hp you didn't lose much. Losing 3 hp out of your base doesn't mean anything. It's what you put to the pto that matters.

You can compare two tractors. Say one has 30 hp and 22 hp pto. The other tractor has 27 hp and 24 pto hp. You are going to want the 27 hp and 24 pto hp tractor for sure. This is a common mistake people make when looking at tractors. They pay attention to the full hp and not the pto hp.

yellowsocks93 · Oct 7, 2003

Thats very true Coyboydoc. The nice thing about John Deere is that they actually put out the advertised PTO horsepower.

smilingreen · Oct 7, 2003

Ok, WE WANT PICTURES!!!!!! /forums/images/graemlins/cool.gif /forums/images/graemlins/cool.gif /forums/images/graemlins/cool.gif /forums/images/graemlins/cool.gif /forums/images/graemlins/cool.gif

mainetreeman · Oct 8, 2003

</font><font color="blue" class="small">( I did a little tweaking on the hydraulic system relief pressure and now it's got some power!!
)</font>

Hehe...I did some tweaking on my 790 w/ 70 loader too. I traded it in for a 4710 w/460 loader. Of course it cost me about 15k more than the shims. But I gotta say I really, really, really, like the lift capacity now.....lol Sorry just got my new 4710 and couldn't resist gloating a bit....

My 790 was a great tractor. It did alot of work that it probably wasn't designed to do. Did you know that 790's will start right back up after tipping over?? Don't ask how I know its a long story. But I used my 790 last year to haul out my christmas trees. I have a Christmas Tree Farm. I was towing a 16' equipment trailer with about 50 trees, up and down hills in the snow, and mud. Course I had chains on it but it did the job well. Except the transition from flat to slope was a little unconfortable when the trailer started pushing the tractor around. Thats the main reason I decided to go with a larger heavier tractor....

JimmyD · Oct 11, 2003

I think JD is now using the engine for the 790 that they put in the 4210. If they didn't do it to save cost they may have done it because of availability. The high demand for the 4310, which is a higher profit unit for them, may have played into their decision. My dealer was not aware of the change until I told him about it.