Hello Everyone, I am new to this website although I have read some of the forums when just conducting Google searches, seems to be a very informative and helpful way of sharing information, so I thought I would give it a try. I am a contractor located in Iowa; we are not real large contractors (2 dozers). We are currently looking to purchase a new dozer; I am upgrading a Cat D8K. In 2011 I upgraded a John Deere 850J to a new D6T (IT4); we really like the Cat dealership and want to stay with the Cat brand tractors. The D6T XW has worked out very well, although is a little small therefore I am looking for a larger sized tractor so my Cat dealer set me up with demo’s on a CAT D7E and a CAT D8T. Both machines had pros and cons, after running each in a side by side comparison I thought there would be a stand out machine but neither really did, so we’ve been weighing options and are still on the fence about which direction to go. We do a lot of farm based work (terrace, waterways, ponds, building pads,etc.) and often find ourselves working in some softer under foot conditions, therefore we buy wider pad machines, our D6T is an XW with 31.5 inch pads and works very good. The D7E we are looking at will be standard gauge machine equipped with 30 inch pads (very similar ground PSI to D6TXW); the D8T would be an LGP configuration (38 inch pads – also similar PSI as D6T XW). My synopsis; a D6 is a grading tractor, the D8 is a bulk mover and the D7E is alternative machine used to grade and bulk with, so ideally the D7E would be the way to go BUT after operating the D7E and a D8T in a side by side comparison proved different results than I would of originally thought. The D7E acts like a D6T in weight and power pushing the blade of the D8T. The D7E is a little easier to transport and build terrace with but the D8T pushes more (like when pond building, bulking) and to my surprise the D8T I felt was a little easier to fine grade with, I think the bogie wheels helped the most with the fine grading though (excellent ride quality), the D8T is incredibly well balanced tractor. The D7E is very responsive (with the electric drive) but the 8 has more grunting power. The D7E cab has more leg room and is very comfortable, but so is the D8T (just not as much leg room on D8T), although the D7E has better visibility to the blade. I have a semi (7 axle) so to transport either machine isn’t a huge concern. If the D7E offered a bogie suspension (like the D8T), weighed in about 68,000 (instead of 57K) and had another 35 horsepower it would have been a clear winner. Both machines have their strong and weak points; I can see either as the addition to my fleet. Please reply with any additional information, please share stories or advice or feel free to ask any questions, any information and opinions is greatly appreciated. Thank you in advance for your replies.
Whichever way you jump have you considered the more advanced electronics (and in the case of the 7E the electric drive system) and how your maintenance capability would have to change from the tractors you had before..? If it was my money I'd go for an 8T. Based on limited experience with them they appear to be pretty well bullet proof. If I could get one with brake & clutch steering instead of differential steering that would be a bonus. (that last comment is purely based on experience with 9T's equipped with differential steer)
I like the idea of the D7e electric drive system, but the jury is still out whether this will be the way of the future or a sidenote. Even if it does prevail, I don't like to buy new technology in it's first incarnation until it has proven itself. Let the big companies take the risk, I can't afford to be wrong when I can only afford to buy one. Nige is wise, you can rely on his advice. Nice dilemma to be in though, post back and let us know what you end up buying, and how it turns out.
The D8T is a proven platform with great parts availability and repair knowledge.
Or 7XM D8R is one heck of a tough reliable strong unit as well as a bit simpler.
Thank you to all for your comments. There are some excellent points made throughout the comments. Excellent forum, I had overlooked some key notes when weighing the pros and cons. We are not real large contractors and I feel we have one shot to make the right choice; again, both machines have their strong and weak points but from what I’m reading here I am seeing a heavy swing towards D8T. Serviceability is a good subject to have been point out to me; with the D7E Cat technicians will be less experienced and parts will be less likely in stock and most likely specialized parts (for the electric drive) will be very expensive, But on the other hand, the D8T requires oil services, filters, routine maintenance checks and has mechanical wear points where as all those points are eliminated with the D7E’s simple electric drive system. The D8T is a more “main stay” tractor. Keep the comments/opinions coming!
Either way if you can buy new equipment you are doing something right. Doze on
Not sure if you considered the cost difference between undercarriage replacement. I'd be interested to see how much an LGP 8's undercarriage would be to replace. Last I remember a standard 8 was around 60K.
There's another thing to consider here. Cat introduced the electric drive in the D7 size machine for a reason - The D6 & D8 together outsell D7 in number of units sold by a factor of about 20:1. The D7 is an "in betwen" size so that IF the electric drive experiment goes South (and I'm not suggesting that it will) then Cat haven't lost huge quantities of sales. Now - your initial question was do you go for a 7E or an 8T...? My first reply was on the assumption you are planning on buying new. Have you considered the option of used machines in the same size bracket..?
Nige, I would be interested in your opinion regarding diff steer vs. brake and clutch. I very much like the diff steer - but that could be a thread of it's own. One other thing that I haven't seen comment on is to consider resale value. I'm pretty sure the 8T will hold it's value very well, but not so sure about early editions of D7E. I understand that fuel consumption on the electric drive is supposed to be better (less).
reliability and performance wise our D8T was great. 22000+hrs and it was still on the original engine, tranny and driveline. It just burned on us, she's gone. Sawdust and chips built up under the cab.
Any reason for this? I had always thought that a D7 was about as big as you can go and still be able to transport it relatively easily? D8's requiring a heavier float and escorts etc. Therefore I had always presumed that D7 would be a quite good seller. Maybe the transporting rules are different overseas?
Our laws are pretty simple. Just haul your load on Sundays or after dark. And avoid scales. I don't know his overall length, but with 7 axles he should be good for 96,000+, without to much paperwork. Overall width might make him have a pilot car or two. Nothing major imop. Edit, I didn't realize just how heavy a 8T was. There will be more paperwork..
Thanks for the comments guys – keep them coming! We currently have a 7 axle semi, In Iowa we can go up to 156,000... The D8T LGP is 83,324 lbs., putting us at a total of 130,000 lbs. on our truck. The D8T does require an escort (1 for Iowa – all that is required) which isn’t a big issue, couple “oversized” signs, flags and a light on a lead pickup and you’re in business. Hauling shouldn’t be an issue... Getting lots of Pro’s here for the D8T, which is good, I think a D8T will probly be the better choice And yes, avoiding the DOT (even when your legal) is best
Bad experience is the answer. Mechanically all you're doing is replacing a clutch in each FD on the conventional machine with the hydraulic motor and gubbins of the diff steer mechanism on the diff steer tractor. To me (puts maintenance hat on) the complexity of the hydraulics and all of the diff steer far outweighs a simple pair of clutches. Also if you have to pull the FDs off to overhaul the brakes every once in a while (which you will) then why not overhaul the steering clutches as well while you're in there..? Have you priced a hydraulic diff steer motor lately..? it's about the same price as a transmission. It's telling that diff steer has never been released on every model, just a few selected ones. A bit like the electric D7 really. Note: Operators may not agree with me, but they generally speaking don't have to fix 'em.
Simple. The D7 is too small to be a big machine and too big to be a small machine.
I haven't been on an 8T Nige, but have a lot of a##e time on 6N's, and have to say compared to the M's, they are far more productive on the type of work that size machine generally does. Your big mounts, 9 and up don't generally do anything too technical, so there'd be no real advantage having the manoeuvrability of diff steering. I haven't had problems with the steering pumps but suspect when they do play up it is down to enthusiastic use more than inherent weakness, like when "operators" on hystat machines do unnecessary neutral turns and strain the drive motors, final drives and tracks.
You're probably right, if you want to steer anything like a 9 and larger when you're pushing a full blade of dirt all you need do is just use the tilt to drop the corner of the blade the way you want to go. Still pushing balls out with both tracks, the extra load on one corner of the blade will make the machine go round in a curve.
I live in sw iowa and there is very little conservation work left undone here. Most farmers all have their own yellow toys now and don't hire much. You are very lucky. Best of luck, either tractor will do well.
And... mechanics generally don't have to run them. I think ih100 hit it in the head regarding the size of machine and the type of work being done. I really like diff steer on 6Ns through 8Ts though. I have run a few Komatsus (D65 and D135? I think), that were nice hydrostat machines, but I much prefer the direct drive feel in the Cats. I am admittedly biased though.
I would keep your d6 and buy the d8t with the price of the 7e it's not worth it, just a over priced d6. D7e pushes liked6r and cost like a d8
I have a D-8T, and it is only the second NEW machine for me. It has right around 9,000 hours on it, and until recently has been a very good machine. It was bought during the building boom, and spent the first 5,000 hours doing GPS finish work. It had nearly zero problems in the beginning, and doing finish grade work, the original undercarriage went 5,500 hrs. It then got rails and sprocket segments, as well as much tougher duty work, and made 8,800 hrs before getting all new Cat undercarriage, with the exception of the idlers, which were welded up and resealed by the Cat dealer. The undergear ran about 40K, so added to the rails and segments earlier, I got 8,800 hrs for under 60K. There has been very little mechanical problems with the machine. What there has been a lot of is electrical problems, starting about 6,000 hrs, and getting progressively worse. The ECM is the latest in a string of electrical problems. It was causing the machine to overheat, even though there was no mechanical reason for it. It turns out the fan is variable speed, and controlled by the ECM. The ECM would not tell the fan to speed up and cool the tractor down, but it was not running slowly enough to tell with out a RPM meter to check it with. I would think in a failure mode, it would default to the highest fan setting, but that does not seem to be the case. It has also had sensor issues, wire looms with short circuits in places that visually check out good, just broken wire inside the coating due to too light of a gauge wire, and a host of other hard to troubleshoot and repair problems. I have been very happy with the D-8T, until the electrical gremlins set in. At the current time, the money spent on electrical problems is neck and neck with the cost of the undercarriage. I would have never expected that. I ran a D-7E in a demo session once, and thought it was the best dozer I had ever ran, but looking back on it, due to all the electronics I would be afraid of it. I am NOT talking about the drive system, but all of the machine controls. If I had to buy another comparable dozer, and there were no limits due to emissions regs, etc, I would look for a low hour D-8R series II. I believe when looking back, it will be the last truly great D-8. As a small to mid sized contractor, when making a purchase such as a new D-8, it needs to work reliably for many years and be able to be counted on to be available. The "hidden" problem with the electrical issues is the time to repair it. I have been down for 3 weeks getting the latest problem diagnosed and repaired. If it was a mechanical problem it would have been a day or two, but electrical eats up time and money like nothing else. With the ease of operating comes a difficulty of repairing. These machines are too costly to be built as a throwaway like so many other things in our modern life.
Well stated JDOFMEMI. Especially about the diagnosis cost of electrical problems.
Yair . . . Bloody amazing (and frightening) is all I can say. Cheers.
Electronics will only get more involved as we go. Its cheaper to put a wire from point a to b with controls then an actual linkage as of old. Understanding the electrical systems woill be key today on. Understanding PWM systems is a plus , the other , different systems use different voltages which sets another problem the echo effect. One system wigs out due to another irregular voltage , these can be lower than .01 . This floors your old school mechanic , because its doing one thing but the computer points else where. Old schools wants to go by his gut feeling. 953C went to neutral with brake locked while moving . Not a trans problem , temp sender was faulty telling the ecm to park it. And it parks without warning. New temp sender , ready to roll . 150$ part , trip to Lex and back up and running. The dealer would bill out around 1500 or more for this repair. If it were my choice , fuel would be the deciding factor. The 8T is solid , the 7E , well look at locomotive technology , underground mining technology , even cars . Electric drive its self is not specifically new , to a track tractor yep. But what do I know , I run a D39E-1 Komatsu .
Hi all Electrics dont be afraid of them. Done a lot of reading onthis forum,mighty fine place to be.Well if u are a small contractor go the D7E dont let electrics scare u off.Look at Wabco some of the best machines ever made the only reason they are not around today the lack of understanding of electrics .Saw a company buy a fleet of Komatsu 630 trucks had nothing but trouble for 6 mnths when they shipped off a bunch of fitters to japan and got them trained up properly never had any more problems with them.Watched a lot of cat techs try to repair electrics with computers the only time i ever saw any good results was when cat was told put it on the float and take it back,then all sorts things happen.Could tell u alot of stories about electrics as far as i am concerned they are as good as u look after them.If u are having electrical problems that equate to the value of the track gear get rid of your electrical team fast that is your true liability.
Yair . . . old man dirt I think if you read the post again you will realise comment is from a small contractor who probably does not have an "electrical team" . . . like a bloke I knew a few years back trying to put two blades wide of fenceline clearing around sixty thousand acres of goat country with a fairly new D6, it bloody nearly broke him. I have no knowledge of modern machinery but have kept in touch with the industry sufficient to be aware that despite your assertions most heavy equipment of the present era has some inherent unreliability due to inadequately designed and manufactured electrical/electronic components. No doubt this state of affairs will improve but to assert that all is rosy at the moment in the field of engine/machine management and control implies a head stuck deeply in the sand. Cheers.
Hey mate if the transportation isn't a prob go 4 the d8 there have been a lot of good points raised by out her people here is my 2 cents worth. If u look at what a d8 can shift in a day then compare it 2 a d7 then look at the fuel consumption the 8 is the clear winner and there still a very snappy and moonoverable the profit margine will b greater this will allow u to get more work and bigger jobs. Also there is nothing u can do with a 9 that I can't do with an 8 and still use less fuel,except maybe in hard rock. The pendulating undercarriage is brilliant better traction better use of the torque and a better ride and not really that much more expensive. U will find u can trim with an 8 quite well once u get used to it I can about 60 mill by eye and arse over about 200 meters and with laser gear about 25 mill same distance. The diff steer is a no brainier it's very reliable and it is impossible 2 slingshot the drives giving better component life 2 the drive line and the whole tractor really. That way it's not so scary to hire someone to drive it ITS HARDER TO HURT. I could go all day about the prose in my mind the only draw back is its harder to shift. Something to remember but if your doing any chaining u gota have a mate 4 it or if its mate is smaller at least a direct drive machine to match it. However if we're my money and someone mentioned this b4 about second hand I would b on the hunt 4 a series 2 D8R although a bit shorter they put more power to the ground use less fuel they still have a mechanical fan (less hyd) a better cooling system with a high speed fan put in my mind they are the ultimate ag dozer.
to jdofmemi.. how else can cat get you to trade more often?
Planned obsolescence is key to keeping machines rolling off the lines, you stack enough high hour failure prone equipment or need to update with newer/faster PLC modules and more efficient electrical gear and the need to replace machines becomes ever greater. My old AC machine is simple, straight forward hard parts, pieces that today are becoming scarce, that is the Achilles heel to those machines as is the electronics of the newer machines.
Yes, but they may not like the trade in my case. It has really soured me on new iron, and buying good used models before the electronic infestation and getting quality rebuild work done seems to me to be a far better deal than new.
Your in catch 22,since you live and work in Calif ! There regulating you out of busniess or into retirement.It's coming even where soon or later. Either you will have to buy new or retro fit the old if possible. Rebuild is on my list here. As far as the original post goes and being close to the poster i would stick with with getting 2 more D6T or R's.Doing farm work here D6R or T is the machine of choice not D8T.You can own two machine for the price of one D8T. You can be working two jobs at once compared to one with the 8.PLus when you have wet spring here like we usual have the 8 will be setting more then running.Can't charge farmers what the machine is worth,and moving will be a pain. Guy close to be has two old 8H and has went to D6R in the last couple years because he can't charge what he needs too and get work to keep them running.They both have set all fall and he has been runing the R'S,each to his own. This coming from a contractor that has been doing farmwork for the last 40years and still doing it.D6R high track has replaced nearly all the D7G around here.Reliablity,dependable and low cost to operate tops my list!!!!!!
I totally agree that the d6 is by far one of the best machines ever built. But if u already own 6es why not go the 8 the dirt u can shift the hard rock ability if pulling scrub no matter virgin or light regrowth the spread ( distance apart ) is greater and daily country covered verses the fuel burn the 8 is actually cheaper to run front the contractors point of view and from the clients point of view it's also cheaper it may take a while 2 catch on, But if look at wat it can do in an hour verse the smaller 6 it's still cheaper to run I 1st learned this when running 8s and 6s in the same paddock pulling and had just started converting the cost 2 an acre rate the cost to the cow cocky its by far more economical to have 8s. I would strongly suggest comparing the component life of the two u will find the bigger tractor lasts longer because its not working as hard. If pushing contour banks or dam sinking or turkey nest building the 8 is still the winner convert the cost to a cubic meter rate and u will find the 8 is in front it is also heavier and will give better compaction both from track rolling and dirt sliding on dirt. The 6 may b easier to use on the batters but once u figer out the 8 u will love it. It may b different in Luther parts of the world but in Australia our properties r big our paddocks r big our contours banks r long our dams r big so for the work done against the price of fuel verse the hourly rate and the component life as well as component cost u won't beat the 8. And there not that hard to shift u only need a pilot to shift them here oh and 4 rows of 4 on the float. Go to a nine and u need police escorts pilot cars permits a quad dolly under the float and its just a headache. Obvisually a 6 or 7 is easier 2 shift 3 rows of 4 is plenty no dolly no dolly no pilot vehicle is a pice of cake. But pilot cars are cheap and plentiful here so to shift an 8 is not that big a deal.
Yair . . . Cam85 . Bloody hell mate, its good to have someone on here who talks Queensland English! I see a fair few dots there, but you're still a bit lousy with those commas and white space. (he grins) Good post and I agree with you completely although I have never driven the modern stuff. I believe your comparisons in size of 8 versus 6 are valid going back to year dot. Did you see the pictures of our 1965 scrub nines here . . . . . . Cheers.
D7E LGP if you can swing it, you can push what an 8 can but go anywhere a 6 would. love this dozer
Thanks scrub I had a look at those photos yea the gear I started on wasn't much newer than that. I had upgraded hydroliks and pilot moters had the electric motors on them but not much different. The first 6 months I was wondering what the hell I had gotten into,what a learning curve now days I call it the learning curve from hell. The old bloke trying to teach me nearly went mad and every time I slingshot the drive I owed him a beer ( he drank a lot 4 a while ). But what an adventure and looking back what an experience 4 a young bloke,funny I ran into the old feller the outher day And I cannot thank him enough 4 having the patience to teach me. He got his revenge but now Ime the one pulling my hair out trying to teach someone else and he thinks it **** funny
You state you already have a D8K.Is it worth spending a lot of money on a dealer certified rebuild or a very good fitter?. I have wondered wether a low houred ex military K with a modular aircon' cab would do the trick.It would be considerably cheaper than a new 8T and there aren't any electrics.It will allways sell for good money and with the aircon modular cab,it wouldn't be too hard on the operator.You are a lucky chap to be able to afford a new 8T and if I could afford one,I would buy one!!!however,I could stand sitting idle a £100k cert rebuild 8K but couldn't stand sitting a £400k 8T if work went quiet.
Scrub, cam, always a pleasure and a delight to read the 'Queensland English' as you gents get on the posts. Can be a little disconcerting to define some of the slang but fun too! Almost as odd sounding to us yanks as our slang is to you.
DaMiller thanks mate and yes sometimes the lingo can b a challenge,keeps us thinking but. Nicky has a good point if it were my money I'd get a d8r series 2 and keep the k as a mate 4 it. Then aim 4 a second d6 then u have a pair of each competitive pricing and versatility is a tool most usefull. Think about it. Hey Blackearth u wanna weigh in here and tell us wat u think.
They do nave thier own tous You are right Old dirt , I would advise him not too over spend , things can go sour .