F250 7.3L or GM 2500 6.6L (LLY/LBZ)?

[joeprunc]

We are looking at upgrading our truck to a used 3/4 ton (under $25K) and have narrowed it down to three. Most importantly I am looking for reliability and longevity. I want our next truck to last at least 300,000 miles. Secondly mpg is also important, but I think these will have pretty comparable mpg (I drive like a grandma).

1. 2004.5-2006.5 Chevy/GMC K2500 4x4, crew cab, short box with LLY 6.6L diesel.
   
2. 2006.5-2007.5 Chevy/GMC K2500 4x4, crew cab, short box with LBZ 6.6L diesel.
   
3. 1999-2002.5 Ford F250 4x4, crew cab, short box with the 7.3L diesel.
   

What truck would you go with and why?

Being an engineer I over analyze everything and its making it hard to pull the trigger on one. It is also hard to find these trucks in good condition, with lower mileage in our price range. There are features on both trucks that I love. But again reliability is most important.

I want the motor as stock as possible.

I do not care about other makes or models, I have narrowed it down to these three.

[12bruckd]

I am a GM fan at heart so i am a little biased. But the Duramax is one of the best diesel motors around. I have driven the 7.3 and it seemed under powered to me. Reliability will be no problem with ether motor IMO. I would go with the newest one with the least miles at the best price you can find. Just dont get a 6.0 Ford, bad motors there...

[Hans Schmid]

#2 would be my pick due to the idea that the LBZ engines had all the injector problems fixed over the LLY engines. The LBZ engines were regarded as some of the best engines made combined with the Allison Transmission you couldnt go wrong. The LMM (08-10) IMO are the best due to not having to run DEF like my LML engine. Only 2 companies make tuners for my engine and both of them I have had problems with so I refuse to run them now. Stupid GMs and their "un-crackable" computers.

As for the 7.3l, great engines but they drove like a tank, were very loud and didnt get the best fuel mileage. The reliablity was there though........

Edit: I also own a KTM so what would I know!?

Edited December 5, 2012 by originalmonk

[k.g]

You want reliability, go with the Powerstroke. My 7.3 has 170k on it, I know the history of it since day 1 and NEVER had a single problem out of it. Most of those miles were spend pulling.

[firehunter]

Well, my wife and I both drive 7.3's that fit your description and are very happy with them. Mine just turned over 208K yesterday and I am still on the original clutch and u-joints. I have replaced the injectors in my truck but that was just to go larger and to replace them on my terms and not when they decided to leave me on the side of the road. I replaced them at 195K feeling that the new injectors would easily get me to 300K and beyond. I did the work myself and the truck was down a total of 6 hours. Of course my truck has a custom chip to go with the injectors

My wife's truck is an auto transmission which we also replaced at 190K before it went out, again thinking that the new Ford HD unit would easily get us to 300K. Otherwise, her truck just has a chip (with gauges) and has plenty of power to pull any of our trailers. She still has the stock injectors but I am getting ready to swap those out on my terms as well.

Both trucks get 17-19 mpg when empty and 10-12 when towing. My wife pulls a 4-horse GN all over the west with nary an issue. Both trucks have had the CPS go out suddenly but I carry spares (~$30) and can switch them out in 10 minutes.

We owned a GM one ton at one time and liked the power and was very comfortable but when it came time for repairs I found that I could not perform "simple" repairs on the truck without buying special tools. I have done ALL of my own repairs on the Ford's myself (including the injectors) with no special tools. I like that.

[joeprunc]

The LB7 motors were the ones with large injector issues (I think there was a class action lawsuit against GM for the issues), the LLY allowed easier access to the injectors for replacement, and helped cure the problem from what I've read. LBZ cured the injector issues, and upped the hp. The LBZ motors are more desirable, and go for more than the LLY, that is why I have the LLY in my list, I have found two LLYs in my price range with ~80K miles, all the LBZs have higher mileage and are more expensive.

I do really really like the history of the 7.3L, and love hearing first hand how much customers enjoy them, but its getting harder and harder for find one with lower mileage. The downside of the 7.3L is my wife does not like how noisy they are compared to the 6.6L.

Thank you for the posts, please keep them coming.

[Hans Schmid]

The LB7 motors were the ones with large injector issues (I think there was a class action lawsuit against GM for the issues), the LLY allowed easier access to the injectors for replacement, and helped cure the problem from what I've read. LBZ cured the injector issues, and upped the hp. The LBZ motors are more desirable, and go for more than the LLY, that is why I have the LLY in my list, I have found two LLYs in my price range with ~80K miles, all the LBZs have higher mileage and are more expensive.

I do really really like the history of the 7.3L, and love hearing first hand how much customers enjoy them, but its getting harder and harder for find one with lower mileage. The downside of the 7.3L is my wife does not like how noisy they are compared to the 6.6L.

Thank you for the posts, please keep them coming.

I think a lot of people compare the 7.3 to the 6.0l engines too though. Comparing those 2, ya the 6.0l had its problems but was a very good engine.The 6.0l design came from europe where diesel is much much cleaner then anything in north america. Adding a variable vane turbo AND EGR to dirty diesel made for bad results. Thats another story though......The 7.3l just never had the problems though. But comparing a 7.3l to a newer 6.6l from GM, its like comparing a Ford Ranger to a Ford Raptor. The 6.6l are just so dam good. The smaller turbos allow the engine to build RPM quicker, the IFS can be a wash depending on your terrain but it makes for a car like ride on the highway. I dont feel the GMs/Chevys receive larger tires as well due to the IFS. The 4x4 system on the Fords are pretty bulletproof with the manual looking hubs but the turn switch system in the GMs are quite good for the lady when the going gets tough.

[firehunter]

I do really really like the history of the 7.3L, and love hearing first hand how much customers enjoy them, but its getting harder and harder for find one with lower mileage. The downside of the 7.3L is my wife does not like how noisy they are compared to the 6.6L.

Thank you for the posts, please keep them coming.

True story. If noise is an issue then your decision may already be made for you. Between the LLY and the LBZ, I would wait to find a LBZ any day. Find a nice one anywhere in the country, fly to it, drive it home.

[joeprunc]

True story. If noise is an issue then your decision may already be made for you. Between the LLY and the LBZ, I would wait to find a LBZ any day. Find a nice one anywhere in the country, fly to it, drive it home.

Noise and comfort are not a deal breaker for us (but I feel GM has the upper hand there).

How loud is the 7.3 when you are driving inside the cab? I know most say to just turn up the radio, but I do like talking to my wife on road trips. I'm use to driving my truck with mudders so we are use to some noise. I'm asking because I just found a 7.3L that is a few thousand $ below our price range and has under 100K miles.

[sniper_101]

I have a 7.3 at 200,000 miles + that I love, but if I had to go GM, it would be an LBZ.

Both great trucks, both have one positive point the other doesn't. Test drive both!!

[leafsrule16]

I can't personally speak for either but I know my father's 7.3 has over 250,000 trouble free miles on it as a tow truck. His 6-Blow (6.0) fared much worse but he has always had a few 7.3's troublefree in the stable. The 7.3 is a good motor in any form be it the IDI, the 7.3 non turbo or the newer turbo 7.3's and you can't go wrong with any of them. They did the truck in light duty tow trucks for the last 20 years no problems.

[firehunter]

How loud is the 7.3 when you are driving inside the cab?

Well, obviously I don't think the noise is to bad or I wouldn't have spent 200K miles in two different trucks in the last 12 years.

When kept stock the engines are pretty quiet. A lot of folks put an open element, free flowing intake system on the engine and that really increases the noise. I opted for an aftermarket intake but the filter is completely enclosed so the noise level is stock. On the various forums there are many folks that have done sound deadening of the cab with good results (Dynamat, weatherstripping mods, even the "beer coozy" mod? ). Cruising down the highway it is easy to have a conversation with all the passengers and my truck actually makes less noise when towing than when empty - but that is because of my modifications and tuning. I have A/T's on the truck right now but there were plenty of times that I could hear the M/T's over the engine noise so if you are used to mudders it shouldn't be too bad, IMO of course.

[souliog]

I am a CAD designer that works on full-size truck frames so I can give you some input.

I have a 2000 F250 with 235k on it. Reliable engine but it has it's problems. Oil pan is rotting out because it was e-coated and not galvinized. Same issue with the Rear Diff cover. Small parts got replaced like alternators, water pump and glow plugs with relay. Trans is also all original with Amsoil fluid since 200k. Cam Position Sensor has been recalled and I haven't had that issue again in 65k. Sheetmetal on the Ford is much thicker than the GM because Ford has a unique design truck. Same goes for the glass. GM is carry over 1/2 ton BIW and interior. The 7.3l is a powerful motor it is just the truck is very heavy. Brakes are beefy and you can get 50k between pad changes. No issues with warpped rotors. Watch out for the caliper pins. They like to seize up and require a torch to free them up. Interioir is spacious and only needed to replace the power door lock motors.

All 3 of the vehicles are "Old" technolgy frame design. Box sections in the front transitioning to open "C" section rears. Everything designed for duability, not for stiffness. We refer to it as "bend but don't break." The gauges are much higher everywhere for the super-duty Ford. This helps the GM feel much faster than the Ford. Weight is a big deal and that's why most people feel the super-dutys feel and drive like a tank. I would not recommend tailgate mounted salt spreaders or the bigger 8' snow plow for the GM. I designed a Patch Kit 2 years ago for the GM that should be available if you want a plow but it is just a welded on patch peice. (The UCA rear bracket was shearing off the top of the front rail)

With that I would say.....1. Buy a gas engine and 2. Buy a 2010 or newer GM. The frame is decades ahead of everyone else in the market for heavy trucks. Diesel is expensive, stinks, noisy and hard to start.

[GNARVAN]

235K on my Powerstroke van with only a transmission rebuild. it will be hard to find a low mileage 7.3.

I want a low mile 7.3 Excursion !

[Sheebanman57]

My dad's 2000 7.3 F-250 has somewhere in the 450,000 mile range right now, and still going strong. He had to replace the motor at 320,000, but that truck gets worked hard. And still if you can get 300,000 miles out of a vehicle, your doing pretty good especially with how much hauling he does with it. One issue we had is it's automatic, and the tranny went out 5 or 6 times. it would've never done that so much, but the guy he kept taking it to, in my opinion, is the worst mechanic i've ever seen. Any reputable shop should've fixed it right the first time, or maybe the second time, not five tries later. Also the original tranny didn't go out until 175,000, and after the botched "fixes", it would go out at least once a year. One year it went out three times. Finally it hasn't gone out for quite some time now. So i don't really think it's the truck fault on that. These engines are a bit down on power, that thing was a dog until he chipped it, after that it pulls everything with ease. Another time you might want to look into is i believe the glow plugs are known to go out on these engines a little more often that most diesels. Other that that she's a great truck and my dad is still extremely happy with it. Also i don't notice the noise everyone says, maybe I'm just deaf.

And my brother has an 07 duramax, and that's a nice truck. Lot's of power and that alison tranny is just smooth as butter... yummy... But i can't tell you too much on the duramax, he's only had it for about eight months. But i think with either truck you won't be disappointed, good luck!

[joeprunc]

I am a CAD designer that works on full-size truck frames so I can give you some input.

I have a 2000 F250 with 235k on it. Reliable engine but it has it's problems. Oil pan is rotting out because it was e-coated and not galvinized. Same issue with the Rear Diff cover. Small parts got replaced like alternators, water pump and glow plugs with relay. Trans is also all original with Amsoil fluid since 200k. Cam Position Sensor has been recalled and I haven't had that issue again in 65k. Sheetmetal on the Ford is much thicker than the GM because Ford has a unique design truck. Same goes for the glass. GM is carry over 1/2 ton BIW and interior. The 7.3l is a powerful motor it is just the truck is very heavy. Brakes are beefy and you can get 50k between pad changes. No issues with warpped rotors. Watch out for the caliper pins. They like to seize up and require a torch to free them up. Interioir is spacious and only needed to replace the power door lock motors.

All 3 of the vehicles are "Old" technolgy frame design. Box sections in the front transitioning to open "C" section rears. Everything designed for duability, not for stiffness. We refer to it as "bend but don't break." The gauges are much higher everywhere for the super-duty Ford. This helps the GM feel much faster than the Ford. Weight is a big deal and that's why most people feel the super-dutys feel and drive like a tank. I would not recommend tailgate mounted salt spreaders or the bigger 8' snow plow for the GM. I designed a Patch Kit 2 years ago for the GM that should be available if you want a plow but it is just a welded on patch peice. (The UCA rear bracket was shearing off the top of the front rail)

With that I would say.....1. Buy a gas engine and 2. Buy a 2010 or newer GM. The frame is decades ahead of everyone else in the market for heavy trucks. Diesel is expensive, stinks, noisy and hard to start.

Thank you for that great response. I actually don't need a diesel for my towing/hauling, and a 1/2 ton would probably work just fine for 95% of the trucks life, so I'm not really that worried about the frame as much as the powertrain. The reason I'm looking at a diesel is because I've always heard that a diesel motor will outlast any gas motor, and longevity is a major criterion in my purchase.

I would love to get a 1/2 ton 4x4 gasser, with 4 full doors & a 6 1/2' box in my price range, but you have to jump to a 3/4 ton to get the full box (unless its a new F150, which I can't afford). So then with the 3/4 ton you are stuck with the larger motors, which get worse mpg that the diesel and are not known to last as long as the diesels. And buying used there isn't that much of a price difference between the gas motors, and diesels.

[souliog]

Thank you for that great response. I actually don't need a diesel for my towing/hauling, and a 1/2 ton would probably work just fine for 95% of the trucks life, so I'm not really that worried about the frame as much as the powertrain. The reason I'm looking at a diesel is because I've always heard that a diesel motor will outlast any gas motor, and longevity is a major criterion in my purchase.

I would love to get a 1/2 ton 4x4 gasser, with 4 full doors & a 6 1/2' box in my price range, but you have to jump to a 3/4 ton to get the full box (unless its a new F150, which I can't afford). So then with the 3/4 ton you are stuck with the larger motors, which get worse mpg that the diesel and are not known to last as long as the diesels. And buying used there isn't that much of a price difference between the gas motors, and diesels.

OMG...if a 1/2 ton is within your needs, then get one. an 04 or newer F150 will have a modern frame architecture. Sadly, GM will not be up to par until the new 2014. Also the 2010 or newer F150 will have the latest "shear" mount bushing technology between the frame and BIW. GM will have it as well in 2014. This is why the 2010 got rave reviews and accolades in ride and handling with the latest F150.

ENgine wise, You can replace a worn out gas engine with 300k on it for less money than the fuel pump and injectors on any diesel. Our local school district replaced our entire school bus fleet with gas engines because:

1. The reliability of a modern gasser is much better than even 10 years ago.

2. Diesel is up to $0.50 -$1.00 a gallon more with very little improvement in economy.

3. far less maintenance cost

4. Quicker turnaround and less man hours to repair gas.

5. Catastrphic engine failure is a fraction of the cost vs diesel.

If 1/2 ton is not available or affordable and 3/4 ton is the only option, then I'm leaning towards a 6.0l gas 2500 GMC/Chevy. Good reliable truck especially since you won't be abusing it too much. The 6.0 gas has a lot of power with much better fuel economy than a 5.4l triton ford motor. And the 2500 series GM trucks ride far better than any super-duty.

[Hans Schmid]

OMG...if a 1/2 ton is within your needs, then get one. an 04 or newer F150 will have a modern frame architecture. Sadly, GM will not be up to par until the new 2014. Also the 2010 or newer F150 will have the latest "shear" mount bushing technology between the frame and BIW. GM will have it as well in 2014. This is why the 2010 got rave reviews and accolades in ride and handling with the latest F150.

ENgine wise, You can replace a worn out gas engine with 300k on it for less money than the fuel pump and injectors on any diesel. Our local school district replaced our entire school bus fleet with gas engines because:

1. The reliability of a modern gasser is much better than even 10 years ago.

2. Diesel is up to $0.50 -$1.00 a gallon more with very little improvement in economy.

3. far less maintenance cost

4. Quicker turnaround and less man hours to repair gas.

5. Catastrphic engine failure is a fraction of the cost vs diesel.

If 1/2 ton is not available or affordable and 3/4 ton is the only option, then I'm leaning towards a 6.0l gas 2500 GMC/Chevy. Good reliable truck especially since you won't be abusing it too much. The 6.0 gas has a lot of power with much better fuel economy than a 5.4l triton ford motor. And the 2500 series GM trucks ride far better than any super-duty.

I owned diesels up to 09 where I bought a 09 GMC 3/4 ton gasser. Though gas has all the power behind it as a diesel, the fuel economy was the shits. The best I ever got was 15.5mpg, downhill, wind at my back. Loaded, 7-9mpg same driving. I have a new GMC diesel and after putting 70,000km in it in the last 8 months, I WILL NEVER GO BACK TO A GASSER. The fuel economy alone is up 3-5mpg and easily the same when loaded. Though I see the initial cost savings owning gas 1/2 tons (I own a construction company and have 3 1/2 GMs for employees), my diesel does the hard work. The GMs 1/2 tons just pull apart after enough hard towing so the initial saving becomes a wash if I have to replace either the trans or the running gear after 150k. Buy heavy duty, buy diesel........

[souliog]

I owned diesels up to 09 where I bought a 09 GMC 3/4 ton gasser. Though gas has all the power behind it as a diesel, the fuel economy was the shits. The best I ever got was 15.5mpg, downhill, wind at my back. Loaded, 7-9mpg same driving. I have a new GMC diesel and after putting 70,000km in it in the last 8 months, I WILL NEVER GO BACK TO A GASSER. The fuel economy alone is up 3-5mpg and easily the same when loaded. Though I see the initial cost savings owning gas 1/2 tons (I own a construction company and have 3 1/2 GMs for employees), my diesel does the hard work. The GMs 1/2 tons just pull apart after enough hard towing so the initial saving becomes a wash if I have to replace either the trans or the running gear after 150k. Buy heavy duty, buy diesel........

I agree with you because you work your vehicle. Sounds like the OP is using it for personal use only.

My friends 2013 GMC 1/2 ton with the 5.3 gas gets 21-23 mpg Highway depending on outdoor air temp. 70-75 mph with the cruise and no more the 500lbs in the box. 18 mpg communting back and forth to work. Dodge's latest 6 cylinder gas with 8-speed trans will do 18 city and 25 highway.

[Hans Schmid]

I agree with you because you work your vehicle. Sounds like the OP is using it for personal use only.

My friends 2013 GMC 1/2 ton with the 5.3 gas gets 21-23 mpg Highway depending on outdoor air temp. 70-75 mph with the cruise and no more the 500lbs in the box. 18 mpg communting back and forth to work. Dodge's latest 6 cylinder gas with 8-speed trans will do 18 city and 25 highway.

Yup, your about right in mpg on the GMs. But hook a 5000lb trailer behind a half ton and it pretty much cuts that fuel mileage in half. The only other thing I hate about half tons that unless you special order, they only come in short box form......

But back to the OP question, the newer the GM the better. Nothing against the 7.3l but it is quite a bit louder inside and outside the cab when compared to a newer GM and you will never get the ride quality or fuel mileage.

EDIT: And you cant have a 3/4 truck and ask for great fuel economy either. 7-8000lbs rolling down the road and the abilty to pull 12,000lbs+ doesnt allow you 30mpg. I have personally seen trucks diesel trucks do 25mpg but it is VERY rare. My GM is babied has gotten 20.1mpg hand calculated but that was on it very best day and me driving better then normal.

Edited December 6, 2012 by originalmonk