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Medium duty diesel information???

Discussion in 'The Garage' started by KrebsATM02, Jul 28, 2003.

  1. KrebsATM02

    KrebsATM02 1/2 ton status

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    I'm looking for forums and webpages to find out more about medium duty diesels. Cat, detoit, and cummins. My plan is to buy a late 80's medium duty truck and transplant a diesel into it if it doesn't have one already. Right now i'm just trying to get good information about which one's better, what transmissions are best, etc.... I already know about TDR but can't search without paying for a username....I guess i'll do that if it comes to it.

    This is all for a crazy tow rig/RV that I plan on building!

    Thanks - Doug
     
  2. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    Yeah, me too what he said.
     
  3. kennyw

    kennyw N9PHW Premium Member

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  4. KrebsATM02

    KrebsATM02 1/2 ton status

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    Thanks, I knew of that site, but it's mostly light duty diesels. I'm looking for info on cummins, cat, and detroit and the transmissions associated with each....I guess i can only dream there are boards like this, POR, etc... about bigger trucks
     
  5. BlueBlazer

    BlueBlazer 1/2 ton status

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    Just my opinion, but your best bet would be an early 90s Kodiak or Topkick with hydraulic brakes (unless you want air brakes) and a single rear axle with the Cat 3116 and either an Allison AT545 or a Spicer 6 speed.
     
  6. ben427

    ben427 1/2 ton status

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    Even the old 8.2 detroit V8s and cummins 8.3's are good little engines.I'm not a fan of the 3116/3126 unless you can afford to buy a new one with the 7 year warranty. We have owned 8 topkicks with 3116/3126 and ALL of them had to be replaced (under warranty) before 200,000 miles. This is in a gravel truck with max gross of 56,000 and 4.63 gears. so it wasnt being over exerted either. Now in an RV application you may not have a problem as it wont see day to day useage. As far as trannies the allisons are okay, but i'd prefer a eaton/fuller 6 or 7 speed. Some topkicks come with a light 8LL which is a really nice transmission with deep reduction, but probably overkill for an RV.
     
  7. BlueBlazer

    BlueBlazer 1/2 ton status

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    If the 3116 or 3126 went bad 7 times, why the hell did you buy an 8th truck. Im sorry but I call BS on this one. If our engines had that bad of a track record, then no one would be buying them up like they do. Im curious to know what went bad on each one of them that warranted a full engine replacement.
     
  8. ben427

    ben427 1/2 ton status

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    I will haul back on one statement, they were not all replaced as units, but all required major work. We are a fleet of 40 trucks, its not uncommon to buy half a dozen trucks a year. We dont need heavyweight sterlings with a C-10 or C-12 for delivering gravel. So we made the decision to buy topkicks. We bought 6 the first year and 2 the next, and the 3116/3126 is the only engine available in a 300. We didnt have many problems till the second year except for one engine. It would burn 5 gallons of oil between changes (6000 miles). Cat took it and replaced injectors, and said it would be fine, it wasnt. Kept burning oil. So they took it 3 monthes later and did and out of frame on it(1). The next one was pulling hard up two click hill,famous around here, if you can make it up without shifting, you got a hella truck. And it took to clattering, dropped the valve, broke the piston cracked the head broke the liner(2). Sitting outside the scalehouse idling, driver inside wating to be dispatched.Blew the oil line off turbo and ran itself dry(3). It had happened before on the highway, and the driver shut her down. Cat fixed it the first time. Next one SOS came back with high silicon in the oil twice in a row, dealer took it in for an examination, block deck was cracked(4). Coolant going down but not in oil. puddle under truck when parked on weekends. Our mechanic couldnt find anything simple, so sent it to cat, cracked clean around a frost plug, but the truck hadnt seen a winter yet(5). SOS came back with high aluminum in the oil three times. dropped the pan, bad bearings,turned the crank,new bearings, flushed block(6). Truck hauling a tag with a 320LC on it, coming across the 104, takes to hammering. pulls over shuts it off.Spun #6 rod(7). And another one dropped and exhaust valve comin up from the valley hauling topsoil and a tag with a D5.(8) This is one of cats worst engines in my huble opinion, maybe were just haveing bad luck. We have a 3406B 425 with 3.2 million on the block. been majored a couple times. We have owned 3306's 3304's 3406's 3408's,C-10's, C12's a C-16, old low speed D318, D326 and D342s Heck even a V8 D13000 in an old shovel. And we have never seen problems like with these 3116/3126. And those havent spoiled our relations with cat at all. We have 5 980Gs, a 988G, 8 769Ds, a 972, a 980C, an it38G, a 375L and cat gear older than both of us combined, and they still go. The technical communicator ensures that we are having bad luck, and two brand hammering new topkicks with 3126Es arrived in our yard last week. Gonna try them again and see whats changed. With any luck they last till 300,000 and well sell them.
     
  9. ben427

    ben427 1/2 ton status

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    I would also like to add that cat does all of our Truck engine services every 6,000 miles. They also service all of our equipment on site, whether its cat or not. So all oil and filters are what cat specs. SOS is taken every oil change. And for what they are, 3116/3126s do work pretty good, 300 hp/860 lb ft works pretty good for being a lighter duty engine, and the fuel economy is also very good for that small an engine hauling around 56,000-60,000 lbs. Just have to get the reliability up.
     
  10. 70~K5

    70~K5 1/2 ton status

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    [ QUOTE ]
    This is in a gravel truck with max gross of 56,000 and 4.63 gears. so it wasnt being over exerted either.

    [/ QUOTE ]

    Jeezz you guys like to run your stuff hard. I run a 3406B and a RTO15715 trans in my dump truck.
     
  11. Diesel Dan

    Diesel Dan 1/2 ton status

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    [ QUOTE ]

    Jeezz you guys like to run your stuff hard.

    [/ QUOTE ]

    Come up to Michigan where you can gross in at 160,000lbs /forums/images/graemlins/grin.gif. And they still can't figure out why our roads suck!

    BTW, for a light/medium duty truck for recreational use the 5.9L Cummins with say an Allision 545 would probably work great. From what I've heard the 8.2 detroit can be a headache to work on the fuel system.
     
  12. KrebsATM02

    KrebsATM02 1/2 ton status

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    If i'm swapping engines i'd rather just use the 8.3. A little more cost, but from what i can understand more longevity, easier to rebuild, and a whole lot more torque...

    I'm skipping the RV part for a year or so...that can come later. I just want a tow rig that laughs at what i pull with it. That plus being cheaper than a 1 ton is why i decided on a medium duty truck.

    Does anyone know about insurance? If the truck is rated at 25900 and a trailer is rated at 10000 that means i would have to have a CDL in texas. If you are driving something that requires a CDL, but for personal use, do you have to have commercial insurance????

    Thanks - Doug
     
  13. ben427

    ben427 1/2 ton status

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    [ QUOTE ]
    Jeezz you guys like to run your stuff hard. I run a 3406B and a RTO15715 trans in my dump truck.


    [/ QUOTE ]
    Hard?? i fail to see how thats hard. the trucks have the 40 rears and 16 fronts, so its within the capability of the trucks. We have a few ford/sterlings with various versions of the 3406 & 8LL, mostly for pup/tag trailer work. They are great Trucks, but the extra weight costs payload. The more you can legally haul the mre you can make (technically speaking). Although with those trucks we spec out the 66,000 gross, (46 rears and 20 fronts) and this makes up for it. our next sterling is going to bean experiment to see how light it can be with 20&46 axles. As much aluminum as we can use(wheels,tanks,cab,box) hendrickson HN suspension and a C12 430hp with an 8LL. we think we can get it down around 22,000 lbs tare, which wll give us a 22 ton payload /forums/images/graemlins/thumb.gif anywho, ill quit ramblin, i just love talkin about big trucks /forums/images/graemlins/grin.gif
     
  14. 70~K5

    70~K5 1/2 ton status

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    [ QUOTE ]
    [ QUOTE ]
    Jeezz you guys like to run your stuff hard. I run a 3406B and a RTO15715 trans in my dump truck.


    [/ QUOTE ]
    Hard?? i fail to see how thats hard. the trucks have the 40 rears and 16 fronts, so its within the capability of the trucks. We have a few ford/sterlings with various versions of the 3406 & 8LL, mostly for pup/tag trailer work. They are great Trucks, but the extra weight costs payload. The more you can legally haul the mre you can make (technically speaking). Although with those trucks we spec out the 66,000 gross, (46 rears and 20 fronts) and this makes up for it. our next sterling is going to bean experiment to see how light it can be with 20&46 axles. As much aluminum as we can use(wheels,tanks,cab,box) hendrickson HN suspension and a C12 430hp with an 8LL. we think we can get it down around 22,000 lbs tare, which wll give us a 22 ton payload /forums/images/graemlins/thumb.gif anywho, ill quit ramblin, i just love talkin about big trucks /forums/images/graemlins/grin.gif

    [/ QUOTE ]

    I wasn't talking about the axles. What I meant was down here we don't push the motors in our ten wheeler dumps as hard cause we start with a larger motor. Most of the people I work with are running 425hp cats, 400hp cummins, or 430hp Detroits. Then again I have a transfer not a straight dump and when I use the trailer I'm grossing 80K which is the max for Kali.
    On your 56K gross dump with a 3126 cat how fast can it pull a 7% grade loaded MPH? I may give up some tonage but working hourly as I do most the time the contractors are looking at who gets lapped not how much weight you're hauling. I run 1/3 to 1/2 the time as a tenwheel dump and the rest as a transfer.
     
  15. KrebsATM02

    KrebsATM02 1/2 ton status

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    well that is all nice, but could you talk about the reliability of each engine, transmission, rearends..... Also, what chassis you think is the best. Also if you have to have comericial insurance if you are using it for personal use, etc...
     
  16. 70~K5

    70~K5 1/2 ton status

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    [ QUOTE ]
    well that is all nice, but could you talk about the reliability of each engine, transmission, rearends..... Also, what chassis you think is the best. Also if you have to have comericial insurance if you are using it for personal use, etc...

    [/ QUOTE ]

    On insurance, talk to your current insurer, they should know the local laws for your area.
    The bigest drawback for using a meduim duty truck I think will be ride quality and if your wife/GF will be able to drive it. Also if you have to have a CDL who will you be able to split driving duties with on a longer trip. Another thing is "hours of service" rules on how long you can drive too. When I get off work driving a truck I may be "out of hours" for hauling my 4x4 to a trail on a larger rig. And if I have to record my hours of driving back from a trail I could be "out of hours" for work the next day.
     
  17. 89GMCSuburban

    89GMCSuburban 1/2 ton status

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    I can tell you from the trannies I see at work that Eaton's are pretty strong trannies. Mack also makes VERY strong trucks, their trannies are some of the most durable I've seen. If you get a Mack or something with an Eaton (Roadrange) tranny, I don't think you'll go wrong.
     
  18. ben427

    ben427 1/2 ton status

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    In a fleet your not looking for speed as much, but i can see where your coming from if your an owner/operator getting paid ton/mile(do they do this in cali??). Were not worried about how fast it can pull a grade, but i will say its faster than a 240 Ford /forums/images/graemlins/rotfl.gif. Our smaller trucks with the 3126s only get called into heavy work (tag/pup work) when the other (bigger) trucks are busy. And that can be hard on them , grossing 106,000 (tri axle tag and yes its legal!) with a 300, yeah i see what you mean /forums/images/graemlins/crazy.gif.
     

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