Just sold my duramax and i’m looking to get into a cummins. I’m really set on either an 06/07 5.9 or an early 6.7. I know they will both be good trucks but i’m not sure what platform would best fit my needs. This truck will not be my daily driver and I would like to build it to make 500hp reliably for now and maybe more later on. It would tow a couple jeeps occasionally but mainly just be driven around town. The 5.9 coming with less emissions equipment is more appealing but “weight reduction” on a 6.7 wouldn’t be an issue for me, it does seem like parts are becoming more scarce though. I’m also not sure whether the 48re or 68rfe would be better in my application. If anyone has any recommendations or points about either truck it would be appreciated!
06/07 5.9 vs 08 6.7
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I would be open to both trucks and find one with a solid maintenance history and lowest mileage you can afford.
The 6.7 has a better highway transmission with the 68RE, the 2 overdrive gears are really nice. Real transmission tuning is also a stark improvement over the 48RE.
The 5.9 48RE is significantly cheaper to build up and hold power, but the gap from 3rd to 4th (OD) is pretty obnoxious.
The 5.9 has no emissions equipment from the get go, so values are already pretty high.
The 06 5.9s do have a fair amount of electrical gremlins, 1st year of CANBUS, so cluster and TIPM problems are common.
Rust will be a big issue depending on where you live. I wouldn't buy anything with fender flares unless you can take them off. Rockers rust from the inside out and are very costly to repair.
If you do decide on a 6.7, I would ensure you have access to the original emissions equipment. Just in case.
4WD trucks have awful front ends, whatever truck you end up looking at I can almost guarantee you some front end component will be worn whether it's ball joints, tie rods, track bar, steering box, etc. Parts are expensive and add up quick.
I would suggest paying a reputable diesel shop for a detailed inspection, it is well worth the hour of labour they'll charge, and can save you 1000s down the road.
The 6.7 has a better highway transmission with the 68RE, the 2 overdrive gears are really nice. Real transmission tuning is also a stark improvement over the 48RE.
The 5.9 48RE is significantly cheaper to build up and hold power, but the gap from 3rd to 4th (OD) is pretty obnoxious.
The 5.9 has no emissions equipment from the get go, so values are already pretty high.
The 06 5.9s do have a fair amount of electrical gremlins, 1st year of CANBUS, so cluster and TIPM problems are common.
Rust will be a big issue depending on where you live. I wouldn't buy anything with fender flares unless you can take them off. Rockers rust from the inside out and are very costly to repair.
If you do decide on a 6.7, I would ensure you have access to the original emissions equipment. Just in case.
4WD trucks have awful front ends, whatever truck you end up looking at I can almost guarantee you some front end component will be worn whether it's ball joints, tie rods, track bar, steering box, etc. Parts are expensive and add up quick.
I would suggest paying a reputable diesel shop for a detailed inspection, it is well worth the hour of labour they'll charge, and can save you 1000s down the road.
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If you can "mange" the emissions stuff properly, IE it falls off.. The 08 in a heart beat. Be very cautious if it's already deleted, chances are high your buying someone else's problems unless the owner will tell you all about what done and has a tuner in had with the truck. Personally, for me to buy anyone's deleted truck, I want to see it come with the tuner and all the original emission equipment in working order. You don't want to get stuck needing to put it back on and buying all those parts down the road.
Honestly, I just talked myself out of it, I'd buy the 5.9. Easier to deal with the 48RE than it is, all that emission stuff.
Honestly, I just talked myself out of it, I'd buy the 5.9. Easier to deal with the 48RE than it is, all that emission stuff.
That's a killer comment for a 6.7 that still has the emission equipment installed. Also, are you sure you're ok with 12-16mpg tops? It takes a lot of highway driving to get above that.
Thanks for the reply ! I’m looking for one as close to stock as possible. Thankfully rust isn’t much of an issue down here in Arizona. I definitely understand the whole keeping the emissions stuff, that’s what I did when i had my duramax. The 5.9 is really appealing to me just because it never came with any emissions junk so it’s never a possibility that it would be an issue (legally). Unfortunately the one i was eyeing looks to have sold so the hunt continues. I have been finding 5.9s cheaper than 6.7s interestingly though.
My situation and area would allow for me to currently have all those parts fall off of the truck but i’ve only found what looks to be a solid couple of options for intake horns and such for a 6.7. i wouldn’t buy a deleted truck from anyone, im looking for as close to stock as possible. Is that 12-16mpg loaded or unloaded? My duramax got 16-17 unloaded most of the time while missing parts.
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If you’re driving around “town”, with stop signs, red lights and traffic, yea 12-16 REAL hand calculated mpg is very likely yes. That’s kinda worse case tbh. There is a ton of variables there.
I mean if you me duramax for 16-17, I’d bet the Cummins would be in the same range.
I’m in the 18-19 range? But I go a good 20 miles drive down the highway to the office pretty often often not. Not a lot of spotting here I’m at. I’m actively keeping my eye out for a commuter car at this point still.
Right, i already have my commuter car for school (100 mile round trip) so mpg on the truck isn’t a huge issue. Whichever i get won’t stay stock, just trying to decide which would be a better starting point for my goals.
2007 Laramie 3500 5.9L DRW Crewcab LB 4x4 48re 4.10 FASS165 G&R Sump Pacbrake PRXB 31k miles
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To get and hold 500HP reliably and with better stock steering, the '08 6.7 and 68RFE. I won't address losing weight.
It's going to cost some bucks to do it right with the 5.9 and 48re, not just adding a tuner.
Just curious if you've driven a 5.9, and does it feel like it can haul a couple of jeeps? You may not need that extra HP. Admittedly, I'm a 16 month old newbie to diesel and still honeymooning with my 5.9, and my upgrades, so have never sat in anything else RAM nor feel I need to. I'm in CA, and stick my tongue out at every make and model with full emissions. With the 3500 DRW, and all that rubber on the ground I don't feel any limitations nor would I worry about hauling a couple of jeeps. It's got more power than I will ever use.
It's going to cost some bucks to do it right with the 5.9 and 48re, not just adding a tuner.
Just curious if you've driven a 5.9, and does it feel like it can haul a couple of jeeps? You may not need that extra HP. Admittedly, I'm a 16 month old newbie to diesel and still honeymooning with my 5.9, and my upgrades, so have never sat in anything else RAM nor feel I need to. I'm in CA, and stick my tongue out at every make and model with full emissions. With the 3500 DRW, and all that rubber on the ground I don't feel any limitations nor would I worry about hauling a couple of jeeps. It's got more power than I will ever use.
My power goal isn’t really intended for towing mainly for fun. I’ve driven an older 24v and my last duramax and even with the stark power difference i know a 5.9 would be able to do what i need when it comes to towing.
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100% incorrect.
You make it seem like the 68 won’t need attention at 500hp (which is absolutely nothing for a CR). I assure you, a stock good condition 48re will hold and last longer than a stock good condition 68. And it’s cheaper to build and will ALWAYS hold more power than a 68.
Simple facts.
2007 Laramie 3500 5.9L DRW Crewcab LB 4x4 48re 4.10 FASS165 G&R Sump Pacbrake PRXB 31k miles
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Can't tell you how much I appreciate your conviction and experience especially as I am a 5.9, 48RE owner and glad about it. I am absolutely convinced that a built 48 is among the best there is. I'm not convinced that a stock 48 or 68 will hold up to 500hp while stock. That's not from experience that you may have though. Just my research from places like here and reading a lot of other experienced folks.
Be sure that I was not comparing the two trans side by side. I was responding to the OPs question of which may be the best combo to make 500+ hp. Given a blank check I would stick with my 5.9 and 45 all day long.
Please correct me if I'm wrong but isn't it a long and expensive road to reliably get there though?
From the OP:
"I'm really set on either an 06/07 5.9 or an early 6.7.
This truck will not be my daily driver and I would like to build it to make 500hp reliably for now and maybe more later on."
Since the 6.7 has about 45 more hp with greater displacement, a vgt, etc, wouldn't it be a less expensive starting point to get to 500hp?
So the real question is not which is the best trans but which is the least expensive route to get to 500hp. Trust me, I'm all ears, as I too may be interested down the road,
Thanks!
Be sure that I was not comparing the two trans side by side. I was responding to the OPs question of which may be the best combo to make 500+ hp. Given a blank check I would stick with my 5.9 and 45 all day long.
Please correct me if I'm wrong but isn't it a long and expensive road to reliably get there though?
From the OP:
"I'm really set on either an 06/07 5.9 or an early 6.7.
This truck will not be my daily driver and I would like to build it to make 500hp reliably for now and maybe more later on."
Since the 6.7 has about 45 more hp with greater displacement, a vgt, etc, wouldn't it be a less expensive starting point to get to 500hp?
So the real question is not which is the best trans but which is the least expensive route to get to 500hp. Trust me, I'm all ears, as I too may be interested down the road,
Thanks!
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Transmission is the ONLY factor in what will reliably hold 500+hp. Because literally, 500hp, at the tires, is nothing more than a tune. It’s not expensive, nor long. It’s 5-7 minutes to program….
But with a 6.7, you have to do exhaust work for reliability because the non-DEF system is a joke. So, that’s even harder to do nowadays since that isn’t as open as it used to be.
So, 5.9: a tune. That’s it, that’s the build. 500+ at the tires
Now, 6.7: a tune. Exhaust. 500+ at the tires.
That’s easy enough, no? Now let’s talk reliability: that VGT on the 6.7 won’t last as long as the non-VGT the 5.9 has. Ever. The motor will fail at some point, requiring either a whole new turbo, or a new motor (assuming the collar isn’t coked so much it can’t move). And that calls for calibrating the motor so off to the dealer or a shop.
Transmission: the 48re is way stronger than given credit. The worst part is the converter, but a $73 shift kit will do wonders. The 68, the valvebody will absolutely leak pressure at some point. That’s why billet bodies exist, to add beef and have a perfectly flat mating surface and reduce that chance. Some are putting a gasket between the body and plate. Shafts and clutches to really hold for both.
But with a 6.7, you have to do exhaust work for reliability because the non-DEF system is a joke. So, that’s even harder to do nowadays since that isn’t as open as it used to be.
So, 5.9: a tune. That’s it, that’s the build. 500+ at the tires
Now, 6.7: a tune. Exhaust. 500+ at the tires.
That’s easy enough, no? Now let’s talk reliability: that VGT on the 6.7 won’t last as long as the non-VGT the 5.9 has. Ever. The motor will fail at some point, requiring either a whole new turbo, or a new motor (assuming the collar isn’t coked so much it can’t move). And that calls for calibrating the motor so off to the dealer or a shop.
Transmission: the 48re is way stronger than given credit. The worst part is the converter, but a $73 shift kit will do wonders. The 68, the valvebody will absolutely leak pressure at some point. That’s why billet bodies exist, to add beef and have a perfectly flat mating surface and reduce that chance. Some are putting a gasket between the body and plate. Shafts and clutches to really hold for both.
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I ran the stock 5.9 HE351 with 200% injectors on a 6.7 swap for about 2 years before it finally let go in grand fashion while passing an RV. The fuel combined with the air volume of the 6.7 had to just be torture on that little guy. Truly was a sad day, the little turbo that could
2007 Laramie 3500 5.9L DRW Crewcab LB 4x4 48re 4.10 FASS165 G&R Sump Pacbrake PRXB 31k miles
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LOL! The little turbo that could! That's a great story even if a sad outcome. So you ran the HE351 stock, no wastegate or other adjustments? I have a lot to learn yet.
I'm no fan of the vgt either. Question: If you had upgraded the HE351 would it have better matched the fuel and air intake of the 6.7?
Final question, besides the tuner, on the 5.9 would it be best to upgrade to head studs, larger valve springs, push rods, larger injectors, more air in and out, to constantly and reliably push 500+ hp?
I'm no fan of the vgt either. Question: If you had upgraded the HE351 would it have better matched the fuel and air intake of the 6.7?
Final question, besides the tuner, on the 5.9 would it be best to upgrade to head studs, larger valve springs, push rods, larger injectors, more air in and out, to constantly and reliably push 500+ hp?
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Yeah stock HE351. I didn’t intend on running it that long, it was temporary until I got my trips rebuilt. And that didn’t work out for me.
Evem stock would be fine on the 6.7, the 6.7 comes stock with the same compressor side but obviously variable exhaust side. Yeah a modded HE351 would likely have been better, but not with that large of injector.
I’m reality, none of that stuff is needed. 500hp really isn’t much, the engines are overbuilt from the factory as-is. Lots of coin to be spent for no real reason.
Evem stock would be fine on the 6.7, the 6.7 comes stock with the same compressor side but obviously variable exhaust side. Yeah a modded HE351 would likely have been better, but not with that large of injector.
I’m reality, none of that stuff is needed. 500hp really isn’t much, the engines are overbuilt from the factory as-is. Lots of coin to be spent for no real reason.
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Or a newer 6.7, 13+
i don’t wanna deal with def
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