TowRig.com - Diesel Discussion and Tow Tech

I am going to get a diesel in my next truck. I currently have a 2500 Dodge Quad Cab 4x4 with a Hemi, which, apparently, is junk for towing, according to some people on here. I have not had any problems towing anything with it. OK, now back to my question. I am planning on getting a diesel within the next year or so. I am looking at the Cummins and Duramax/Allison. Powerstroke is out of the question, not a Ford guy. Which one, in the real world, is stronger, better, more fuel efficient, etc? In other words, give me some of you experiences with both. I'm leaning toward the D/A in a GMC because of the smoother riding IFS 4x4 versus the straight front axle Dodge, and they look better than the Chevys, but, I like the Dodge trucks, too. My last 4 trucks have been Dodge. Since I am on the subject, has anyone heard of Chevy changing the grille/headlights on the new Silverados, like the '07 Tahoes/Avalanche/Suburbans? BTW, I tow a 1000 lb ATV/trailer combo, a 3500 lb ski boat, a 5000 lb tractor occasionally, and I am getting a 9000 lb bumper pull travel trailer within the next 6 months. waytogo

If your wanting a manual, either would be fine. Id prefer the dodge if I was gonna get a manual. If you want an auto, the Dodge dosent even compete with the GM. I had a Dodge, my parents have two, and my Duramax tows better honestly. My trucks an 02, my parents have an 03 Dodge with the auto. The Cummins has alot of power, but with that auto, it just doesnt perform well. Only has 4 gears compared to the Allison 6, and the shift points on the Dodge just dont feel right. Having a 03 Dodge compared to the same setup on an 02 GMC, the duramax wins hands down. juts my $.02

Thanks DMAXRIG, I also like the 6 spd Allison. One of my bud's has an '06 GMC, D-Max, Allison, and it is bad a$$. I love to drive it, just have not towed anything with it. I have yet to drive a new Cummins.

Fuel mileage wise, the Dmax and ISBE are about the same, but if I had to choose one the Cummins has historically beat up on the other two with mileage.

The 48RE is a fine transmission.:rolleyes: It handles a 610 cummins no problem and for what small towing you are doing that shouldn't be a problem either. Something else is that the 48RE costs a lOT less to modify than the Allison. You can make 47/48RE laugh at the Allison with about $1,800.

The Allison has 5-6 gears, definantly an advantage, but if you waited a while longer you could get a 6.7 Cummins with an Asin 6 spd auto.

Inside and out I like the Dodges better, better looking and a cool looking and comfortable interior.

I am not a fan of IFS. It has a better ride, but I like the stability the beam axle and it's stiffness that makes it feel like its stuck to the road. Also I think the Dodge and Ford D60's can hold up more weight.

I am going to get a diesel in my next truck. I currently have a 2500 Dodge Quad Cab 4x4 with a Hemi, which, apparently, is junk for towing, according to some people on here. I have not had any problems towing anything with it.


BTW, I tow a 1000 lb ATV/trailer combo, a 3500 lb ski boat, a 5000 lb tractor occasionally,

Thats why. 5K isn't much, most small gas engines like the Hemi can easily handle this weight, and really doesn't fall much short of the cummins in both in town acceleration and in the hills, because there is no weight there.;)

Hook that 9K RV trailer to your Hemi Ram and you will see a big difference that extra 4K over the tractor makes. Fuel mileage will fall through the floor and you will take hills with patience.

The Cummins on the other hand wouldn't be able to tell much, or care about the extra 4K. Fuel mileage wouldn't drop more than .5-1.0 mpg and wouldn't hardly slow it down up grades.

Does this make the Hemi junk in a 3/4 or 1ton? No, just inferior. I think they are great engines in the magnum and the throw back small 2wd pickups. They work fine in a heavier truck as long as you don't tow big weight.

Yes, the trannsmission isn't the best for towing, and it doesn't compare to the Allison. With that said, the Cummins is strong enough to keep up with any other truck with two less gears and an inefficient torque converter. If you think you will put money into the truck and transmission, then the Dodge can't be beat when the 48re is built. They will both pull fine, but the Dodge is the best for low end torque. It's gonna make your hemi seem like a 4 banger.

They are both fine trucks, each with strengths and weaknesses. Stock for stock the DMax/Alli combo currently provides more power, torque, and transmission strength than anything else available. And an Allison with nothing but a converter and Trans-go shift kit will easily match ANY <$2000 Dodge auto build for less money. But the GM manual has serious issues with the dual-mass mistake that GM continues to force on the public. So if you want a manual, I would lean to a Dodge or figure in an upgrade to the wheel/plate/clutch within the first 20k or before heavy work or performance upgrades.

If you want 4x4, then which is better depends on your intended use. IMO, SFA wins this point ONLY if you want to run big tires/lift and/or do significant off-road explorations. If your primary interest is in towing and road use with support for the occasional camp grounds, fields, snow, and so on; then the IFS GM wins in every category. And that is based on physical laws and established facts, not opinion and seat of the pants evaluation. And also note that “ride” in the typical sense has nothing to do with IFS vs SFA, though the much higher unsprung mass in SFA can contribute to ride quality issues and definitely (according to EVERY book or authority on the subject) contributes to handling problems. These things are often mistakenly attributed to “ride”, which is for the most part a function of spring rate and dampening rather than suspension design which is only a secondary contributor along other factors (chassis rigidity, mass, tire composition, etc.). For those who prefer anecdotal support, consider this. If IFS was superior for some reason, what are *all* 2WD front suspensions (other than MD and heavier trucks) and most handling oriented rear suspensions implemented as more expensive and complex independent designs? SFA has its benefits and uses, but trying to claim SFA superiority for street use does not stand up to rational/logical examination. Heck, 2 out of 3 of my 4x4 trucks have SFA, and they each work best for the application! For me, SFA certainly does not eliminate a truck from consideration, but give the “point” where it’s due. Some people simply prefer SFA for whatever their reasons may be, but then again, some people also prefer to believe that a whirly thing in the intake, or magnets on the fuel line, or K&N filters increases power and fuel mileage. ;) :stir:

I would suggest doing like I did when I chose my Silverado. Go to several dealerships and drive each one. Not just around the block, but arrange to take it for an extended trek. I drove each one for several hours, and the Silverado for a full day, before making my decision. And even arrange to do a test tow with your heaviest config if possible so that you can see how it handles under load. Only then can you really know what it best for you. I would never trade my Silverado for any other truck I’ve seen to date (even the new GMs for what that’s worth) but I spent a fair amount of time evaluating the options in detail before I committed to this truck. The effort has been well worth it.

Good idea, drive both and decide for yourself. Worst thing to do is decide on a truck because of being biased towards one. I always thought nothing compared to the Cummins, but I tired to be opened minded and actually found what I thought was a better truck. Let us know what you decide.waytogo Oh, by the way. You never mentioned what you prefered, auto or manual?

And an Allison with nothing but a converter and Trans-go shift kit will easily match ANY <$2000 Dodge auto build for less money.

A quick look at Suncoast's website....

Dodge,
$1,295 for converter
$395 for valve body.

Allison,
$1295-1,495 for converter
$749 for valve body.

Plus I doubt the Allison is much, if any at all, stronger than a 48RE with both transmissions having the two additions listed above.

RJF is right, you pay to play. I doubt the Allison could stand up to an aggressive chip for very long. Sure, we can argue that it might last longer than the 48re, but you're still buyin new parts in the end.

Look, the Allison is a better transmission than the 48re. Even if you built them both up, the Allison still performs better. Why? Because of the shift points. The Allison keeps the engine in the power band better. The worst thing about the Dodges autos, besides the fact the dont last, is that they fall on their face in OD. If any one else here has had both trucks, a newer Dodge and a GM, and thinks the auto Dodge performs better than post it. If you have not had a GM with the Duramax, then dont compare and say one is better than the other if youve never had a fair comparison between the two. Like Ive said, we have an 03 Dodge automatic and an 02 GMC auto, the GMC out performs the Dodge. Will the Cummins out last the Duramax? probably so. Does the Cummins get better mileage than the Duramax? Actually no. I can get almost 20 mpg onloaded on the freeway. The Cummins get between 17 and 18 on the freeway. I like the Dodge plenty, there are a few things I like about it better. But, if someone asked me if I were to buy another truck what would it be? I'd buy another Duramax based on the comparison Ive had between towing with the two.

The Cummins/48RE falls on it's face in OD?rotfl It's locked up in OD at anywhere from 1,500-2,100RPM's, right where the Cummins rolls in massive torque. Falling on it's face and those RPM listings with a Cummins is an oxy moron.

Yes, the Allison has an extra gear (ok, now two, but it's barely out) that does help keep the motor in it's powerband. Does it make that big of difference? Not in my opinion. My "inferior" 4 spd does just fine. I haven't driven a Dmax personally but I have driven a 6.0 Ford with the nearly identical Torque shift. It holds the motor up in the higher RPM range just like my auto with one less gear does. Dmax guys make a big deal because they have an extra gear, having a 4 spd doesn't mean it shifts at 3200RPM's and drops all the way down to 1,500 and has to lug back up. It's called converter efficiency and lockup. At WOT my 4 spd holds the RPM's between 2,600 and 3100rpms, and drops to about 2,300 when lock up hits. The "so much better" 5 spd Ford that I drove and the Dmax's I've ridden in didn't feel that different.

Would I like an extra gear in my trans too? Yeah, it helps winding through roads that are too sharp for full speed.

Bottom line my point was it costs less to modify a 47/48RE than the Allison and I doubt the Allison is all that much stouter when both have different converters and VB's.

Yeah, our truck feels like a geo metro going up a 8% grade with 5 people in it when its in OD.:doah: Actually, it can pull our 6k trailer up to Eisenhower tunnel (elev. 10000+) in OD at 65 mph accelerating and pass anything else with the box off. Oh, and this was before we built the transmission. Just cruising, no foot through the board with the truck screaming at redline. You should get that other truck checked out.

A quick look at Suncoast's website....

Dodge,
$1,295 for converter
$395 for valve body.

Allison,
$1295-1,495 for converter
$749 for valve body.

Plus I doubt the Allison is much, if any at all, stronger than a 48RE with both transmissions having the two additions listed above.

Where did I say "valve body"? I said "trans go shift kit". IIRC, the SC vb is only needed for the top line Stage 5(?). And Suncoast is only one converter producer. Plus, there have been guys running 200hp VA boxes pushing 900+ dyno'd torque with nothing more than a good single clutch converter and a transgo kit. And that is running 4WD stalled launches in a quarter mile.

Even if we allow that cost of upgrades is a wash, the Allison internals are rather massive compared to the 48RE. The Dodge boys like to tout those pics of connecting rods comparing Cummins to DMax/PSD, but don’t take into account radically different design changes/needs from I6 to V8, but now they ignore the MUCH more massive internals of the Allison which *does* map directly? I don't recall any upgrades for Alli hard parts even on the full boat trans, but (and I'm going out on a limb here, may be wrong) I believe that the typical 98RE rebuilt to handle those numbers and survive under race conditions requires upgraded hard parts. Anybody? Is that correct or am I confused? :confused:

Also, and this is an honest question, will the 98RE with the cheap buildup (converter and VB) tow in OD with the wick turned up? How far? My *stock* Alli has been doing it at +90 on the Edge Juice for several years and 50 odd thousand miles, no problems (yet). However, I will note in the interest of honesty that I turn it down to level 2 (+60?) in the mountains to help control EGT even though I have it set to auto defuel to keep below 1350. But still, I can tow at 15k gross and hold 80 in OD going up a 6% grade. I’m not sure the 98RE in moderate trim could handle that...

But I will agree, either way, you pay to play hard... Question is, how hard DO you want to play?

The *stock* ’02 vintage Alli can handle +90 (level 3/4) Juice (dynos around 400hp/750tq typically IIRC, long time since I paid attention to the dyno day results) and a led foot with sporadic racing/playing. Can the 98re do that? I think we can all agree the answer is no. The 98re needs the ~$2k upgrade to get into that territory. How far will it go like that? Another honest question, I don’t know what it would take. But the Alli with that same ~2k budget upgrade is known to push on up to near 500/1000 territory on trucks that actually drag race frequently. Here I’m just repeating what I read, no idea how absolutely accurate this is, but it should be ball park. But again, for all practical/typical “road warriors” that want a bit more “oomph” than the factory config, they can easily do so with nothing but a stock alli and single chip/programmer, and the new Alli is supposed to be even stronger. With the Dodge 98re, I don’t think anyone would be advised to do much of anything for power adders without upgrading (or planning to upgrade *when* it goes out). It’s a much better trans than given generally credit for, but it’s no Allison...

Also, the extra gears mean it does not need to slip the converter (as you mentioned on the re) but can stay in lock up more. That both improves efficiency and reduces heat and wear.

Oh, and when I was looking (quite a while back) at upgrading my Alli so that I can actually (safely) use my upper 2 settings on my Juice/Attitude, it was well under $1500 for the recommended/popular/proven major name single disk converter and trans-go kit.

I dunno, we towed on level 4 with the EZ for a long while with no slipping or anything. Then with the juice, it could be driven on any level, and didnt slip, but it was inefficient. With the hot juice it slipped pretty bad, too much power. We got an aftermarket TC, about 1350 bucks, and their stuff isnt cheap. The VB was about 350, so thats well under 2k. The truck could have run any level but the 180 hp 440 tq setting before building it up. I think ANY tranny will have a bad day with that much power.

Oh, and its a 5 disk converter, for what it's worth, so you know it's good stuff.

The Cummins/48RE falls on it's face in OD?rotfl It's locked up in OD at anywhere from 1,500-2,100RPM's, right where the Cummins rolls in massive torque. Falling on it's face and those RPM listings with a Cummins is an oxy moron.

Actually, our 03 Dodge feels like it does fall on its face once it hits over drive. I like the Cummins, dont get me wrong. It performs alot better with a manual. But, having both trucks, the Dmax just flat out out performs the Cummins in an auto option. Like it or not, thats the truth. Put a manual behind both, maybe different story.

Beeram: You used the top levels on a Juice with no slippage and a stock RE? That's pretty amazing to me, what are the "HP" ratings for the levels on EZ and Juice for the Dodge? With all the 47/48re failures I've seen (and heard) behind mildy warmed and even stock Cummins trucks it's hard to believe it would take those levels unless someone were very gentle with them or you got lucky with the best stock RE ever made. ;) :D Even the Alli won't take level 5 on a *standard* Juice without risking "limping" it on a full throttle launch, even non-stalled. I've done it only twice and man what a ride, but scared to death I would kill my tranny.

Where did I say "valve body"? I said "trans go shift kit". IIRC, the SC vb is only needed for the top line Stage 5(?). And Suncoast is only one converter producer. Plus, there have been guys running 200hp VA boxes pushing 900+ dyno'd torque with nothing more than a good single clutch converter and a transgo kit. And that is running 4WD stalled launches in a quarter mile.

Even if we allow that cost of upgrades is a wash, the Allison internals are rather massive compared to the 48RE. The Dodge boys like to tout those pics of connecting rods comparing Cummins to DMax/PSD, but don’t take into account radically different design changes/needs from I6 to V8, but now they ignore the MUCH more massive internals of the Allison which *does* map directly? I don't recall any upgrades for Alli hard parts even on the full boat trans, but (and I'm going out on a limb here, may be wrong) I believe that the typical 98RE rebuilt to handle those numbers and survive under race conditions requires upgraded hard parts. Anybody? Is that correct or am I confused? :confused:

Also, and this is an honest question, will the 98RE with the cheap buildup (converter and VB) tow in OD with the wick turned up? How far? My *stock* Alli has been doing it at +90 on the Edge Juice for several years and 50 odd thousand miles, no problems (yet). However, I will note in the interest of honesty that I turn it down to level 2 (+60?) in the mountains to help control EGT even though I have it set to auto defuel to keep below 1350. But still, I can tow at 15k gross and hold 80 in OD going up a 6% grade. I’m not sure the 98RE in moderate trim could handle that...

You used the top levels on a Juice with no slippage and a stock RE? That's pretty amazing to me, what are the "HP" ratings for the levels on EZ and Juice for the Dodge? With all the 47/48re failures I've seen (and heard) behind mildy warmed and even stock Cummins trucks it's hard to believe it would take those levels unless someone were very gentle with them or you got lucky with the best stock RE ever made.



You under estimate a 47/48RE. Oh, and it's a 47 or 48RE, not 98. Come on Russ, you should know better than to believe how bad a certain part is just because you hear about it on the internet. Most 47RE and 48RE transmissions live a long life when treated right.

Take a stock 10,000 mile 48RE. Throw away the converter and valve body. Add a Suncoast or any other name brand valve body and converter. You are now good for 500/1000 power. Driving, racing, towing.

After my whole experience I do not trust a shift kit. I have a hard time believing a simply kit is enough to satisfy the Allison. I would definantly go with a full valve body that has been completely machined for better flow, not just different springs.

The Allison does have a leg up when it comes to hard parts, as the 47/48RE's need a billet input shaft, intermediate shaft, output shaft, and a different "certain" drum. All of this isn't needed for moderate power, but all of this would be needed for some of the pullers and racers making 800-1,100HP. Most of the time if you are going to make more than about 450HP a billet input is the only thing you need.

Jeez, where did that "98RE" come from? Maybe because I owned a 98 Ram? Strangely, I must have done that twice since I remember correcting one just like that. :confused: Or maybe the correction didn't get applied? <shrug> But at least it looks like I got the rest of them right...

That's interesting, I didn't think the RE would go that high without more than converter and VB. Thanks for the info.

And on the "kit", it may not have been enough in your RE, but lots of guys pushing major power and drag racing are touting the transgo kit for the Alli. All trans are not created equal, so I have no problem believing the RE (notice I avoid the numbers now! ;) ) needs a VB while the Alli gets by fine with only a kit. But I am only repeating common (very common at that) "hear say" since I have not done this myself...

I wonder how a Cummins with an Allison would perform. I'm being serious, has anyone done it?

And on the "kit", it may not have been enough in your RE, but lots of guys pushing major power and drag racing are touting the transgo kit for the Alli. All trans are not created equal, so I have no problem believing the RE (notice I avoid the numbers now! ;) ) needs a VB while the Alli gets by fine with only a kit. But I am only repeating common (very common at that) "hear say" since I have not done this myself...
Maybe the factory Allison valve body can flow a lot more oil than an RE VB, I don't know. I just know that the big names make a huge deal about how they enlarge all the oil passages for more flow, and so on, for all three brands.

I wonder how a Cummins with an Allison would perform. I'm being serious, has anyone done it?
Probably close to the same, except that you'd hear it shift one extra time...;) I don't see how the Allison converter is any better, or tighter.

The main thing I'd like to have, much more than an extra gear, is the grade braking and simple spin on filter. I can't believe it's taken this long for a factory auto to finally have a spin on filter.

I wonder how a Cummins with an Allison would perform. I'm being serious, has anyone done it?

Not sure, probably would run good though no doubt.

Probably close to the same, except that you'd hear it shift one extra time...;) I don't see how the Allison converter is any better, or tighter.




In my experience, the Allison just feels like it shifts alot smoother and faster. RJF, I recomend that you try and pull a trailer with the Dmax/Alli and see for your self. I honestly use to trash the Dmax cause it was a V8, but once a buddy of mine let me pull a trailor with his truck I was totally taken by suprise. The Cummins is an INCREDIBLE engine!!! With the auto they work fine, but compared to the Dmax/Alli, I truly belive it is just a better combination and will out tow the Cummins with an Auto.

The Allison has 5-6 gears, definantly an advantage, but if you waited a while longer you could get a 6.7 Cummins with an Asin 6 spd auto.


The Dodge 6 speed auto will almost definitely be an 68RFE for regular pickup trucks (ie: not chassis cabs). Iirc it is based off the 48RE so hopefully they beefed up some of the weaker parts. I am all stock, but don't like how the 48RE is shifting lately, only 20K too:confused:

I have never driven a Duramax, but they make it sound like the most trouble free of the big three?
If you want a truck to modify, the Cummins is easy to modify for big power, but the stock transmission needs help. I'm ready to replace my stock converter, it's just too loose after adding 140+ HP over stock.

On my 2001 CTD I put a DTT VB and TC in at 80,000 miles +-. I put a total of 423,000 miles on that truck and I never -REPEAT - never rebuilt the tranny. I used and abused that truck. It had 360 injectors, edge race box, and a few other goodies. The Allison is a great tranny, but there were sure a lot of dodge re trannies spankin their a$s at the DHRA in Houston last month.

On my 2001 CTD I put a DTT VB and TC in at 80,000 miles +-. I put a total of 423,000 miles on that truck and I never -REPEAT - never rebuilt the tranny. I used and abused that truck. It had 360 injectors, edge race box, and a few other goodies.
That is encouraging haha.

im sorry, i really just dont like the duramax, but i agree the allison is a much better tranny than the 48re, all the auto dodges ive driven are worthless! the duramax would run circles around em, but put a 6 speed behind the dodge and wave good bye to the duracrap. i own a 6 speed cummins and have waved bye to plenty of duracraps, but if mine was an auto id be watchin the tailgate of the duramax or powerstroke getting smaller and smaller. well actually alot of powerstrokes beat me now...hmmmm :( o well!

Ever driven a Duramax? :pimp:

i sure have. ive driven about 6 of em. including an 06. and it just doesnt seem to pull as good as the other two. maybe i just happen to find 6 bad ones, but i dont know. ive never drivin a cummins or powerstroke that had a problem with a hill. but i sure liked that tranny. except in tow mode, it jerks u bad.