Hi, I'm in the market for 3500 DRW 4X4 Mega cab and will be stretching it. I didn't see an applicable category for my question so I'll post in both year categories.

I'm trying to decide between an '06/early'07 with a 5.9/48re, and the '07.5 6.7/6 speed auto. Probably can't afford anything later than this.

I've heard there were "teething" problems with the first 6.7s. Have these been (easily)worked out with re-flashes? Looking for some experienced advice on what you would look for - the 5.9/48re, or the 6.7/6 speed; and why? I'm going to have the truck for a long time.

Thanks!

 

since nobody has said anything... guess I'll give ya something.

you're in cali.... smogging diesels now. The 5.9 has a cat.... that really doesn't cut the flow down much.

if you can stand just having a legal intake and chip... you can just pull the chip come sale time or smog time and be happy. a stock 48re isn't great.... if you chip up and add some meat... and still pull a lot, you'll want a built unit. I like the 5.9 as a result. I'm not sure what the did in late 06 early 07 w/ the 5.9.... but I had a buddy w/ one that was a ULSD badged motor... not sure what that does for it positively or negativley... (i'd rather use 2stroke oil)

the 6.7's have proven themselves worthwhile..... probably will have more frequent issues because there are more moving parts. removing those parts is a significant improvement. I have a buddy w/ a 5500... ditched the communist parts... chipped up.. it torches off the duals and has seen 19mpg hwy w/ 4.88's even. once again it's cali... did you want to spend 30 mins swapping to smog.. or 2 days. Not to mention the commies up in sac use rolling smog stations to entrap those rejecting al gore's faggoty.

The 6auto in stock form beats up on the 4auto. (but consider a 5.9 w/ a 6spd manual...rad)

just some stuff to chew on. watch out for prius's writing down your license plate number regardless of smoke or not....

 

Thanks for your reply. I can live with not breathing on the motor heavily, but we may not be staying in CA either. The fascists are getting really hard to bear. I was planning on a reprogramming kits and billet low stall TC to begin with.

I don't understand you comment about 2 stroke oil. Do you use it in lieu of diesel additive? How much per gallon, and does it accumulate any carbon?

What did your buddies do to the motors to get better mileage, especially with 4.88?

Thanks.

 

I just got my mega, and I had the option of the 07 in a 5.9 or the 6.7, I chose the 5.9. I think it boils down to preference, but I know guys making more power with better milage with the 5.9. And I have a dr. perf inline module off my last 06 left over, so that was a perk.

 

If I had to make a choise, I'd say the 5.9L w/ a 68RFE 6-speed tranny. However, they never made them that way.

The 68RFE is by far superior to the 48RE, in my opinion. And since the 5.9L is so much more user friendly and accomidating to bombing, I'd say that it is vastly superior to the 6.7L, again just in my opinion. So, what did I get? An '06 5.9L Megacab w/ a G56 6-speed manual. By far the best combination of anything out there, again, in my opinion. The South Bend Dual-Disk is in the mail, and once it's in and done my days of modding the tranny are pretty much over. I get FANTASTIC fuel mileage with a 5.9L/G56 combo, and it's so freakin' easy to buy mods for it that will kick it up way higher in HP/TQ when the time comes. I DID ditch the cat, but I went with a 4" MBRP that will easily re-accept my cat should I ever have to move to somewhere like Socialisticommiefornia!

 

the 5.9 is more friendly to modifications because they only have the Catalytic converter and the camshaft is designed to where it functions as an egr system without the actual need to recirculate any exhaust back through the motor, the 6.7 is a towing monster, there's no replacement for displacement, however you have to deal with an external EGR system and the diesel particulate filter which is a pain in the ***, if you can ditch the parts you'll have the best truck on the road, 68RE is a better transmission than the 48RE in stock form, built is another story from what i've been told, and the 6.7's turbo has the factory exhaust brake function which is nice if you tow alot or just wanna save wear and tear on the brakes, i know i'd like to have that ability with the 40" tires i have, and the solution to the prius's writing down your license plate number is to put hybrid stickers on the truck, that'll send em for a loop

 

Bobcat67, how heavy do you tow with your Goerend trans, when did you rebuild it, and how has it been? What kind of custom TC lockup switch do you have? If you tow heavy, do you think 2 more gears (6 speed vs. 4 speed) would be advantageous?

Do you mean the camshaft is designed by Cummins with a lot of overlap to purposely contaminate the intake charge (thus functioning like an egr system)? Is this why I've seen people replacing the camshaft in 5.9s with a different grind? Do you know if this makes a big difference in torque or mileage? Thanks!

 

Here's a link to show you what Diesel Power (and their collective wallets) come up with when dyno-ing both the stock and modified 5.9L and 6.7L Cummins engines. This is with the EGR and DPF installed as they are a California-based organization. Also, with the money it would take to buy a 68RFE and transplant it into/onto a 5.9, you could have one sick, over-engineered, and extremely worthy modified 48RE that could handle WHATEVER you might throw at it. I read in a post on here earlier that Top-Fuel guys use the modified 727 Torque Flight (the basis for the 48RE) in their 1/4 mile monsters. That says a lot. They kinda know what they're doing, ya know!

Enjoy the read:

6.7L Vs. 5.9L Cummins Diesel Engines | Diesel Power Magazine Article at Automotive.com

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With one exception, I believe. When it comes to only 40 ft/lbs of torque being the difference, there is, in my opinion, one replacement for displacement. And that would be a little thing called "Fuel Economy".

 

I don't tow to heavy with my Goerend, I have 40" tires, but when i do tow it is amazing, 2 extra gears could be advantageous i suppose, but one thing i've noticed when towing the 68RE searches around for the right gear a bit much, whereas the 4 speed rarely shifts down, if ever, my custom torque converter switch is a $5 radioshack resistor and switch, i just say it's custom cause it makes people think and in regards to your camshaft question i believe you hit the nail on the head