Learn me Cummins 5.9 trucks

I searched but did not see a learn me on this. 
 

I've seen some of these for sale of the salvage auction sight and got me wondering about them for a tow rig/fun truck in the future. 
 

What years to look out for?

Is +100 horsepower really just a tuner away? 
 

If not is there still cheap easy power to be had? 
 

I've noticed, maybe diesels in general, to have low usable RPMs before redline vs gas how does this effect day to day driving?  Does it seem like the transmission is shifting more often? 

Is a gas truck wether dodge or GM a better truck if you aren't towing a lot. 
 

If it's a 12V (twelve valve) you're talking about, they don't use "tuners".  They are fully mechanical.  But there are some cheap and easy tricks to yield +100 hp.  Just YouTube it.

As far as drivability, that's why people want them.  A 300 hp Cummins and a 300 hp gas V8 won't even seem like they're on the same planet if any significant load is involved.  

On the other hand if you're talking about 24V, then yes basically a tuner and a lift pump is all you need, maybe an exhaust too. And you want to stay away from the high output versions. They make a bit more power to start but some part of the fuel system is much less receptive to tuning.

Pretty sure the stock auto transmission is questionable with extra power, though if you're not towing a bunch or otherwise beating on it then maybe it'll be fine. The manual is pretty stout as long as you use the right oil and don't beat on them in fifth gear.

Honestly the rest of the truck around the drivetrain is kind of awful, especially by today's standards. And IMO the dodge is the worst in that regard but the others from that era aren't much better. Giant and unwieldy, noisy, the most uncomfortable seats you've ever experienced, etc. Oh and THE RUST.

If you're not going to be towing much I'd honestly go for the newest gas truck you can justify in your budget. It's the boring answer but it'll be a million times easier to live with in normal use. I have a friend that used to have an 02 cummins and traded it in on a new f150 ecoboost and it's just better at everything, other than towing, by a mile. And even though it's not quite as capable at towing it's still a much nicer vehicle to tow with. It's a bit less stable but you can hear yourself think and your back doesn't hurt when you get to your destination. And we don't have to try to predict which part is going to rust off this week or whether the A/C will work for the next trip.

I have a 6.7 Cummins,  my FIL has a lightly tuned late 5.9. His feels like a real sports car engine by comparison. It's still inside a 7000 lb truck so it's still not a drag race king. 

As for the shifting, that's all about the gear ratios in the trans. My six speed is effectively only a five speed because the low gear is a stump puller, but that's enough range to go from a standstill to an 80 mph cruise comfortably. It's not going to get much over the ton (if at all), though. That's not what they're for.

Around town, the diesels don't make sense. Give them something to pull and they love it. Diesels want to work. 

In reply to dps214 :

Note that the 2010+ Dodges are a big step up in refinement and comfort. Mine's quite a pleasant place to spend a day. 

Keith Tanner said:

In reply to dps214 :

Note that the 2010+ Dodges are a big step up in refinement and comfort. Mine's quite a pleasant place to spend a day. 

Right, basically pick the drivetrain you want and then buy the newest one you can get. But if your budget is 90s/early 00s diesel, think about a newer gas truck unless you're doing something that really needs that 600ftlbs of torque.

How old of truck are you looking at? I have an '01 with a 24V and it is probably the worst generation.  The VP44 injection pump is good for about 125-150K miles before the computer on it gets anti-social and won't talk to the truck anymore. The pump will be fine but the electronics are the problem. Its also the loudest inside the cab. Also look for the block casting number, you don't want one with a "53" block, they are known to crack. The number is on the side of the block on the driver's side near the front. Pretty big, you can't miss it.

I would look for a 2004-06 if I was looking for an older truck. The are a lot quieter inside and don't have all the later emission items that came in '07.

As "bad" as my truck is in the Cummins line I'll take it over the other options available. Its about to hit 375K miles. I spent a bunch of time to quiet the cab with mass loaded vinyl and dyna mat type stuff. I even lined my Banks intake box with sheet lead to quiet the intake.

 I had my trans built by Suncoast Transmissions, it was the fuse in the system before. Now it will handle 600hp/1200ftlb. I have an Edge Comp box on it that claims to put the Cummins at 800+ftlbs.

I don't have a specific budget or years I am looking at. Basically just started watching them on the auction site. 
 

Good to have all the info before bidding though. I have a newer tundra for a nicer truck. This would be more of a "fun" vehicle as I have been interested in diesels but haven't owned one. 
 

It would probably be pre 07 anyways just due to not wanting to spend too much. 
 

Can you get similar power numbers out of the more mechanical 12v vs the newer 24v? 

looks like these are the different year groupings 

I have a 3rd generation Dodge Ram 2500 with the 24 valve 5.9.  Mine is a quad cab, 8 foot bed SLT.  It currently has about 138k miles on it.

While it has been asserted above that the Cummins engine is fantastic but the rest of the truck is bad, I respectfully disagree.  The key to buying one is how they have been treated and how they have been maintained.

My truck had only 2 owners prior to me.  I was provided with a 1.5" thick pile of service receipt history detailing the amount to which the truck has been loved.  It was "fluid filmed" early in its life with accounts for the zero rust.  Most of its services were performed at a dealership.

We own many vehicles, but when I have the need to haul something larger than my V70 can handle, I'm thrilled to get behind the wheel.  I am 6'2" and about 260 lbs and I am super comfortable in it.  This summer my family of four chose it to drive from CT to IA and back, a total round trip of around 2500 miles.  We average just a hair under 21 mpg too.

My truck is the factory "H.O" version with 325hp and 600 lbs / ft of tq.  While I wouldn't attempt to race a new Mustang GT, I find it easily keeps up with traffic.  It pulls our 32 ft 7500 lb travel trailer with zero drama.  Our prior gas Ram 1500 struggled to maintain speed on the highway with that much weight out back.

I've owned it for a year and a half and have put nearly 10k miles on it.  The good news about this era of Cummins truck is that if you step up to buy a nicely preserved one like mine, it will likely be worth the same or more when you decide to sell.

I've owned over 110 vehicles in 35 years of driving and this truck probably makes my top ten.

My point:  get out and look at trucks for sale, drive them, and experience them.  Your take on them may be different than mine or any of the others who replied here.

Good luck in your search.

^^^That is the gen truck you want if you can swing it.

You can get all the power you could ever want out of either engine. The 12V loses drivability when you build up the mechanical pump. Hit a bump and your foot bounces on the pedal, your head hits the back window from the torque. The common rail in the truck above is way quieter and just as capable of making power. You just spend money on different things.

Loweguy5 said:

While it has been asserted above that the Cummins engine is fantastic but the rest of the truck is bad, I respectfully disagree.

Again, that was referring to the earlier trucks, first and second gen. From there every generation was a big step forward in the rest of the truck even if the drivetrain only saw marginal improvements.

Interesting tidbit:  a diesel V8 such as one of the various Powerstrokes or Duramax will weigh between 850 and 950 lbs.  An I6 Cummins will scale in at over 1100.  So there is some beef there.

I had a 12V in a '95/96 4x4 Ram extended cab for awhile.  When it worked, it wasn't a bad truck.  Except most of  the time it didn't work.  And since I don't really have the time or space to work on something that big, I paid a shop to fix it when it broke.  Fortunately (maybe?), I live near a Cummins service center, so I had them do most of the work on it.  Not cheap, but at least I knew they weren't lacking in experience. 

As mentioned, the truck around it is kinda crap.  And gets rusty quickly. 

Transmissions sold behind the 12V are a bit of a double-edge sword. The automatics aren't great, but beefed up versions are readily available. The 5 speed is also kinda crap but upgrading is much more expensive.  My 5 spd had the annoying 5th gear rattle. 

If you buy a Cummins, chances are high it's being sold for a reason. A reason the seller probably won't be upfront about.  The cheaper the price, the more expensive the reason.  So just expect the truck to require some significant repair bills. Maybe you'll get lucky, but I'd err on the side of caution here. 

But when you need a truck to do "truck stuff" a Cummins is nice to have. 

In reply to Somebeach (Forum Supporter) :

Living with a Cummins in the cold.   
    My boss buys 30+ Cummins a  year.  
    One thing that all of them have in common is they are really cold unless they are working.  We have winter fronts ( canvas coverings over the radiator openings )  on from November through March. In December January and February if we're parked with the engine idling eventually the temps inside get way too cold and we're left with shutting off the heaters.  After a while  we choose between reving up the engine trying to build heat back into the engine or shutting it off and accepting the cold.   In 30 below wind chills that's pretty brutal. 
    Another problem that occurs is use of Diesel exhaust fluid. DEF Some years are real heavy users   While other years seem moderate The last problem has to do with fuel icing up.  When it happens the vehicle won't go very fast 30 mph or less at times. Some years are horribly bad while others don't have any problem. We use anti gel. 911 is the best brand we've found. Some anti gels don't work at all.  And all of them seem to take more then recommended. 

Modern diesels with diesel particulate filters (DPF) don't like to sit and idle all day. That can lead to a really expensive repair bill if you ignore the truck's request to go run on the highway for a while to regen (burn off the particulates stored in the filter). I don't think any 5.9s got a DPF. As for DEF, that wasn't used on Dodges until 2013 so neither of these should be a concern on a 5.9.

Dodge diesel trucks have a strong, strong resale. Mine's a 2010 model year and it's currently worth (checks KBB) about 90% of what I paid for it new. I think this is because they're really good at working so they're basically a small business on wheels.

What I'd watch for on a 5.9 is modifications, especially the 12V. They're basically the Chevy Nova of trucks, all hotrodded out the wazoo by kids. You don't want a creampuff that's only been used for occasional Home Depot runs, but you don't want one that's been turned up to 11 by the fourth owner. Ideally, you want a work truck that's being rotated out of the fleet after being maintained by a fleet manager. By this point, that's probably not going to be a 5.9 anymore because they're all 15 years or older.

In reply to A 401 CJ :

Here's some of the BEEF!

In reply to Keith Tanner :

Newish Cummins will automatically idle at about 1200 rpm until the particulate filter is cleaned. 
  Part of what we do is "stay with the team". In other words the coach doesn't want the kids to go from the showers  to a sub zero bus and have to sit for the trip home ( which can be hours depending on where the tournament is. )   
the bus may be warm if it's a big team like football, but a little team like swimming isn't enough to warm up.   Kids want to sit in the back where it's hardest to get heat. Even with a rear booster pump the coolant chills too much under the bus.  And it's a choice between freezing the driver  and the kids. Or just the kids in the back.   

All I can tell you is that I used to manage a 12v and a 24v for work. I put 500,000 on the 12v and 250,000 on the 24v before I left and they were still going strong. They were always under load and generally abused and neglected. I don't know how you kill an old 12v, but I couldn't do it. 

In reply to pinchvalve (Forum Supporter) :

I did.  Not driving them seems to do it. No engine really likes to sit for long periods of time, but in my experience diesels even less so. Mine tended to sit for weeks on end. Granted, I get the impression Keith doesn't drive his truck very often, so who knows. 

The only way I'd buy another 12V Cummins (which is probably the only diesel I would buy again) is if I could completely tear down the truck and restore it immediately after buying it and undoing any PO "upgrades".  Then adding any vetted upgrades during the reassembly.  Of course, this would be time consuming and expensive. 

Frenchy, I think your use case calls for auxiliary heaters. Using an idling diesel to try to heat a school bus in very cold temps just doesn't work. It's the same reason I have a little furnace in my Westfalia.

I don't drive my truck every day, but it's exercised fairly regularly with short trips at least. The light use does concern me. Took it on a 500 mile round trip two weeks ago, so at least it's had some recent highway time. I'm at 90k over 10 years and both the interior and exterior of the truck look brand new when clean. I'm hoping to get at least 300k out of the beast.

frenchyd said:

In reply to Somebeach (Forum Supporter) :

Living with a Cummins in the cold.   
    My boss buys 30+ Cummins a  year.  
    One thing that all of them have in common is they are really cold unless they are working.  We have winter fronts ( canvas coverings over the radiator openings )  on from November through March. In December January and February if we're parked with the engine idling eventually the temps inside get way too cold and we're left with shutting off the heaters.  After a while  we choose between reving up the engine trying to build heat back into the engine or shutting it off and accepting the cold.   In 30 below wind chills that's pretty brutal. 
    Another problem that occurs is use of Diesel exhaust fluid. DEF Some years are real heavy users   While other years seem moderate The last problem has to do with fuel icing up.  When it happens the vehicle won't go very fast 30 mph or less at times. Some years are horribly bad while others don't have any problem. We use anti gel. 911 is the best brand we've found. Some anti gels don't work at all.  And all of them seem to take more then recommended. 

Has your boss thought about a diesel fired pre-heater like the Webasto heater? No more idle, warm coolant, block, and warmish oil and start up. 

In reply to DrBoost :

He buys new and sells at 5 years.  Most aren't used for charters.  So we drivers tough it out. 

Somebeach (Forum Supporter) said:

What years to look out for?

Is +100 horsepower really just a tuner away? 
If not is there still cheap easy power to be had? 
I've noticed, maybe diesels in general, to have low usable RPMs before redline vs gas how does this effect day to day driving?  Does it seem like the transmission is shifting more often? 

Is a gas truck wether dodge or GM a better truck if you aren't towing a lot. 

Ealier 12v Cummins are dead nuts reliable.  The really early ones had a VE pump that isn't quite as versatile.  The later 12v trucks had the P7100 pump which is incredibly bulletproof and easily tuneable with a screwdriver and a piece of plywood.  Not kidding, those are the actual tools you use.  I had a 12v in a 26' box truck and I got tired of slow hills, so I stopped by the side of the road and five minutes later I had 50 more horsepower.

+100 hp is nothing.  With the right parts and some internet solutions, how does +1000hp sound to you?  Dad's duramax has bigger injectors, a lift pump, exhaust, and a tuner.  It puts 938 ft-lb to the wheels for about a $2500 investment.  Zero changes to daily driving, improved MPG, and wickedly fun.  Getting sideways at 70 mph in a dually is fun.  It's not uncommon to see Dmax or Cummins trucks putting out 2000 lb-ft and well over 1000 hp on basically stock rotating assemblies.

The thing about diesels is that they don't have throttles and they do (at least the ones we're talking about) have turbos.  With a gas engine, you're chasing head flow characteristics, fuel trims, cam selection, exhaust selection, compression, etc so that everything matches.  With a diesel, you add more fuel which spins more turbo which adds more air.  Keep going until you run off the map with the turbo.  Install bigger turbo and keep going.  Making power with diesel is dirt simple.

Regarding low redline and shifting... they actually tend to shift less because the broadness of the torque curve means they don't have to.  There is zero impact to driving characteristics.  It's totally transparent.  No different than switching from a 350 Chevy with a 5000 rpm redline to a Miata with a 7500 rpm redline.  Redline is pretty easy to change as well on most of them.  They don't need extra RPMs (and the slower burning of diesel means that you reach a point of diminishing returns) but if you plan on getting serious power, it's a simple offset cam in the governor of the pump in the case of the Cummins.

Regarding whether or not gas/diesel is the best choice for towing, you'll get eleventy quillion opinions on that.  I'm a diesel lover, and towing with Dad's duramax or my 7.3 powerstroke is night and day.  I can tow with my 5.3LS and get 10mpg, or tow the same thing with Dad's hopped up Dmax and get 18 mpg.  I can top a mountian at the speed limit with my 5.3L or his Dmax, but the difference is I'm doing it by carefully timing my shifts and putting my foot to the floor in the 5.3L, or setting the cruise on his Dmax and it never goes past 1/4 throttle.

Be aware that with big torque comes big carnage.  Dodge has two things against it in my book.  Let's say you have a Cummins and a Powerstroke both making 480 lb-ft.  The Cummins does it with an 80 ft-lb "hit" every 120 degrees.  The powerstroke does it with a 60 lb-ft "hit" every 90 degrees.  (that's not really how it works, but you get the idea)  That, coupled with the fact that Dodge never really made a dedicated transmission designed to handle it and you get problems.  They basically took an A518 and kept adding a stronger part here or there and called it a 46RE or 47RE, but it never had the clutch diameter or shell integrity to handle the vibes and the torque.  It's still more or less an evolution of an old Torque-Flite from the 60s.  In my years running transmission repair shops, not only did I see my fair share of insane carnage inside 47REs, I also noticed that the parts to rebuild them are far more expensive.  I could rebuild a Ford 4R100 for $2200 or a GM 4L80E for $1800.  One of the cheapest 47REs I did was more like $3600 for just a standard rebuild.  Since they often broke additional parts, they could get really expensive.

Early P-pump 12v cummins is a good bet, but good luck finding one that isn't rusted or has 500k on it.  The whole engine has basically three wires.  Everything is mechanical and bulletproof.  24v cummins is still a fine choice, but right away you'll need to put a good lift pump in it.  Factory lift pumps tend to die, and if the VP44 injection pump gets starved for just a moment, it's toast.

Dodge gets my nod for diesel engine, GM gets my nod for transmission (allison), and Ford gets my nod for overall fit/finish/build quality.  My dream truck would be an F250 with a 12v cummins and an Allison transmission.  Since a very close second favorite engine is the Dmax, I usually take the easy button and just get a GM and put up with the cheap interior quality and electrical gremlins.  It's the same reason I now have a GM Van.  It was my only way to get a full size AWD van and I just tolerate the foibles.   But if Ford had offered an AWD van, I'd be driving an Econoline right now.

Just drive one or three and get a feel for yourself.  Newer diesels (like post 2008 DPF or DEF equipped versions) can be nightmares, but the sweet spot of diesel greatness is somewhere in the 99-07 range.  If I were shopping for a diesel truck right now, I'd be looking for an 05-07 LBZ/LLY duramax.  If this site you're talking about has some not-wasted Dodges, I'd consider a P-pump 12v or a 24v with a better lift pump.  I just really hate the Dodge part around the Cummins.  Personal taste.  Some people like them.

In reply to Curtis73 (Forum Supporter) :

Great write up thanks. That was all really helpful. Especially the part about dodge engine. GM transmission and ford body. 

In reply to dps214 :

My reply wasn't directed at you, just wanted to offer another viewpoint.  Your points were well thought out and accurate.