Would you go with a 5.9HO or a 6.7?

[cerberusiam]

Anybody have an idea as to the cost of retrofitting to 3. 73s? and yes of course, it's a 4x4, so you get to do it at both ends:{

Around $1000 per axle to change gears, not really worth it.



Actually, 4. 10's with an auto and 33-35" tires would be almost perfect. The 35\4. 10 combo would be close to to the stock tire\gear. With 33" tires you would have a better ratio and not hurt the mileage as much. Plus, the auto would like the 4. 10's a lot better under load.



If I found an auto with 4. 10's for a decent price I wouldn't even think twice about it.

 

[Grinder1]

Around $1000 per axle to change gears, not really worth it.



Actually, 4. 10's with an auto and 33-35" tires would be almost perfect. The 35\4. 10 combo would be close to to the stock tire\gear. With 33" tires you would have a better ratio and not hurt the mileage as much. Plus, the auto would like the 4. 10's a lot better under load.



If I found an auto with 4. 10's for a decent price I wouldn't even think twice about it.

I was thinking the same thing as far as tire sizes go. Factory 265s look too small and kinda wimpy anyway.



Found a 2005 3500 QC SW 4x4 AT w/4. 10s for about 23k. Decent price? In a "dry" market for these trucks, I guess so. Always wish one could get for less $$.

 

[cerberusiam]

I am running just over 1800 rpms at 72 mph with 3. 73's and 33" tires. Towing I would prefer than to be around 2000 rpms because everyhting sounds and feels much better there.



I guess since they are selling 03's for 23k at times that much for an 05 is not out of line. If the SWB works for you and it will work for your trailer its probably a fair price. I would have to think for a while on an SWB but they have their advantages.

 

[Grinder1]

Test drive it and see what the RPM's are at 70 MPH, 2000 RPM is the sweat spot for the HO 5. 9. If you are going to tow more than getting the groceries, go with the 4:10.

I need to do another road test. I think it was turning about 2200 at 70. With 33" tires I should be able to drop it closer to 2000.



When I test drove truck, the overhead display showed 14mpg average. I have no idea how the truck has been driven since display was reset, or how long ago it was reset.



Any idea what the mileage difference would be between 3. 73s and 4. 10s?

 

[bcbender]

You are correct, I have 265/70/17s ( stock ) , and I run right around 2300 @ 70+ I will step up to 285/75s next to drop my 70mph rpm to ~ 2000, but I pull a 10,000 lb 5er and don't know its there:-laf, Ultimately a sound truck that uses a little more dsl is a lot cheaper than rebuilding / repairing one. .



my $0. 02

 

[JJPage]

I am running just over 1800 rpms at 72 mph with 3. 73's and 33" tires. Towing I would prefer than to be around 2000 rpms because everyhting sounds and feels much better there.

Yes cerb, this is real close to where I'm at in OD W/35" tires(70mph@1800rpm). I can just lope down the interstate with my toybox, hardly noticing the gradual pulls and wind, cruise on, it will almost never shift down.



If I do get into a hard pull and encounter sharp corners also, drop it into drive and I can run between 50/70mph never getting above 2000rpm. I agree, while pulling hard 2000rpm sounds better(but in OD your doing 80mph), but cruising at 70mph, 1800rpm in OD is more comfortable than 2000rpm in drive, imo.



Maybe with 4. 10's 70mph @ 2000rpms in OD would be smoother, than 70mph @ 2000rpm in drive with 3. 73's?

 

[cerberusiam]

Any idea what the mileage difference would be between 3. 73s and 4. 10s?

Too much is dependent on terrain, climate, and your right foot to say definitively. With a slightly larger tire on the 4. 10's and driving normally not much difference from what I have heard but its hearsay so who knows for sure.

Maybe with 4. 10's 70mph @ 2000rpms in OD would be smoother, than 70mph @ 2000rpm in drive with 3. 73's?

I don't know about smoother but 2000 rpms in drive at 70 mph should be more efficient overall with a higher OD. Would the better leverage make a difference? Good question.

 

[macdaddy]

Thanks for all the replies guys. The TDR boys are spot on as usual. One rig I'm looking into is an '05 with 4. 10s and 48RE. How's the mileage compared to the 3. 73s?

This is the set up you want. Friend and co worker had 3:73. 1 on a 04. 5 2WD dually 48RE. We switched it to 4:10. 1's on a swap. stock trucks with stock wheels and 48RE's love em



He tows 11K in OD and 13 mpg. About the same as mine.



70 mph 2100 rpm empty with the 4:10. 1's. didnt notice any real negative impact in economy when commuting.



Mac

 

[RVTRKN]

We know the 48re is weak, when considering the massive torque the Cummins has and history of breakdowns. With this in mind I would prefer the 4:10, making it easier on the trans, if I want better RPM vrs MPH, then oversize tires would help.

 

[JJPage]

Well, there you have it Grinder, everyone agrees 3. 73's are the way to go..... :-laf.



It's going to boil down to a personal preference, 4. 10's easier on trans, probably. Running across Montana, towing or empty, 75 mph speed limit... no doubt in my mind what I would prefer.



If you can find a good clean 3rd gen, and it has 4. 10's, auto or 6spd, it may be a "once in a lifetime" find. But we have provided some pro's and con's. Jess

 

[Grizzly]

I would agree that the 6 spd manual is much stouter than the 48RE. Only problem is that my left knee and clutches don't get along too well anymore.



Any way to improve the '05 headlights legally? I know they're WAY better than my '95s.

I drive with my fog lights on while on low beam. It does help, however it is illegal in some states including NM. I've never been stopped for doing so.



george

 

[Grizzly]

I'm sitting here thinking... ... ... ... ... ... . why can't you put a 68RE behind a 5. 9? That would be a sweet ride my friends. Anybody tried it? I'm sure all the computer carp nixes any possibility.

If you're going to go through all that expense and work to swap out for a 68RE why not go with an Aisin. It's better than an Allison.

 

[Grinder1]

Well, there you have it Grinder, everyone agrees 3. 73's are the way to go..... :-laf.



It's going to boil down to a personal preference, 4. 10's easier on trans, probably. Running across Montana, towing or empty, 75 mph speed limit... no doubt in my mind what I would prefer.



If you can find a good clean 3rd gen, and it has 4. 10's, auto or 6spd, it may be a "once in a lifetime" find. But we have provided some pro's and con's. Jess

OK Jess and everyone else, a great big THANKS to all the imput. JJ I take it you're fond of the 3. 73s. :-laf

I also take it that the low mileage 3rd gens are getting tough to find.



I'm thinking the 4. 10s may work out OK with some 285s mounted up. I used an online RPM calculator and came up with some numbers. Using a 33" diam tire, 4. 10s, a . 69 final drive ratio, it showed ~2000rpm @ 70mph. Hauling heavy up a slow tight curved mountain rd. those 4. 10s will be my transmission's best friend. Of course running empty on a long, lonely stretch of hwy... ... ... ... ... . I'll be a wishin' for those 3. 73s. Before I pull the trigger, I'm gonna take the rig on one last test drive tomorrow. Any last thoughts before I bring home a new addition to the fleet?

 

[HBarlow]

Grinder,

When you ask a question like the one that opened this thread the guys who have ISB5. 9s are naturally going to tell you all the good things about their 5. 9s because that is what they own. Some of them have never even driven a new ISB6. 7 with the new six speed automatics.

Thousands of us have bought and really appreciate the 6. 7s. Mine has 100k troublefree miles on it. At least two TDR members have around 350k working and towing miles on their '07. 5 6. 7s. Their trucks have been essentially troublefree also.

I owned a 24 valve '01 and a HPCR '06 before this truck. IMO the '08 is better in every way except fuel economy than my previous two trucks. Owners of the new Gen IV trucks say their trucks are even better. I have not personally even looked at one up close. I don't want the temptation.

All of the Dodges with Cummins engines are good trucks. Only you can decide what is best for you.

 

[RVTRKN]

I've owned both, look at sig, and 5. 9 would be my first choice but they are hard to find. The DPF sucks in any way you look at it, mostly fuel economy, but there are other issues as well that have been posted before. Its a personal choice, HBarlow is talking about the C&C which has less trouble than the reg 6. 7 mostly due to the 305 HP programing. The regular pickup 6. 7 has been improved since 07, but fuel economy still is a disadvantage, and at $4. 00a gallon its a no brainer.

 

[HBarlow]

The actual fuel mileage penalty of a new ISB6. 7 is actually pretty small, regardless of all the outrageous claims of some.

My '01 with manual six speed and 3. 54 gears could occasionally show 21 mpg on the overhead indicator but realistically it did about 18 mpg. Towing a heavy fifth wheel it got about 10 mpg.

The '06, a 48RE with 4. 10 gear would do about 16 or maybe 17 running empty on the interstate and about 10 mpg loaded.

My '08 will do about 14 or 15 at steady cruise, about 10 loaded.

Big deal. A couple of miles per gallon may give some bragging rights but it hardly effects my cost of operation enough to worry about it.

The comfort and convenience of the '08 are much better and the reliability of the Aisin is tremendously better.

 

[EGroeneveld]

I currently have both. I daily drive my 2005 and its been a great truck. My 2011 sits with the slide in camper on it for the next 7 months at least.



If you cann't afford a new truck and like working on stuff yourself, get the 5. 9. They are great trucks.

If you can afford a brand new truck a 6. 7 is awesome. The 6 speed Auto, interior refinements, real CrewCab, and much better ride offset the mileage penalty. For me the mileage appears to be about 2 or 3 less with the 6. 7 verses the 5. 9. The trucks are both 4 door, dually 4*4s. The 5. 9 is 3. 73gears and the 6. 7 is 4. 10 gears. They turn the same rpm (about 72/73 at 2,000 rpm).



You cann't go wrong with either one, get what you can afford.

 

[Prairie Dog]

Have to agree on some points with Harvey. FE of 5. 9's went down the toity on later 3rd gens with the cats, third inj event and all the other crap they loaded them up with. By many reports I've read, the 6. 7 gets at least the same mileage as the later 5. 9's and many times it's better towing.

 

[Grinder1]

Thanks for all the input guys. I came very very close to pulling the trigger on a super clean 05 4x4 tonight. The 05 had 4. 10s, auto trans, and was pretty peppy around town but on the freeway it didn't feel quite like you'd want to drive it cross country. Wondering if maybe I'd better test drive a newer rig yet again, I decided to check out an 09 at another dealer. Naturally it's over $10k more but I gotta tell you, that 6. 7 coupled up to the sweetest 6 speed AT ever put in a Dodge truck, wins hands down IMHO. The gearing in the 68RE along with the 3. 73s seems to be a perfect combo. I will put up with all the extra emissions crap in order to have a more driver friendly rig. So for now I think I'll just keep looking for a great deal on a newer 3rd Gen with the 6. 7.

Harvey you are wise to not drive a 4th Gen, because yes, you will be very tempted. They are by far the most comfortable, driveable new trucks out there. I just wish they weren't so much money! :{

__________________

 

[DogramTD]

Grinder1, if you bought that '05 and we lived closer I'd offer an axle swap. I'm looking for 4. 10's but the boss wont approve the funding. If youre pullin heavy and have tires larger than 33", you'll want the 4. 10's. Since we cant turn overdrive off in the 05, we have to travel 75 to stay in the sweet spot. With the 35" tire/4. 10 gear it puts you right back at stock rpm/mph as if you still had the 3. 73 (agreed that is the best ratio if all were to stay stock)



Good luck on your new purchase... Personally... if i had the cash... the 2010 is one purdy truck!