48RE Vs Allison 1000

[olznut]

When I was in Tx 2 weeks ago, my bud was driving us around in his '05 2500 GMC Duramax. What I noticed, is that at the same speed, he's turning the same rpm's as I am with my 4spd. I thought the Duramax would be turning less rpm's than that. 65mph came in at almost 2000rpm, same as me with my 4. 10's. What's the big deal besides him shifting 1 more gear? Also, it liked to downshift going up hills that I know for a fact mine wouldn't downshift and just pull. It also shifted too soft for my taste. He also has trouble getting more than 13mpg around town, when I'm getting 16. I'd say about equal in the quiet department. Too bad he's die hard GM. I was too, until they killed Oldsmobile. Maybe I'm missing something.

 

[KBalzuweit]

My 06 Dmax turns about 1600 @ 65. Around town not towing I have no problem getting 16, overall its fuel economy is about the same as the 06 Dodge I had.

 

[DPKetchum]

The V8 diesels DON"T have the low end GRUNT the Cummin does. It really dosen't NEED a 6 speed trans. All the Ford Torgueshift does is SPLIT 1st and 2nd gear so it can get a load moving. The V8s have good power but in a HIGHER rpm range like a gas engine. All the going ons about MORE gears and these D. C. trucks never really NEEDED more gears.

 

[jimnance]

The V8 diesels DON"T have the low end GRUNT the Cummin does. It really dosen't NEED a 6 speed trans. All the Ford Torgueshift does is SPLIT 1st and 2nd gear so it can get a load moving. The V8s have good power but in a HIGHER rpm range like a gas engine. All the going ons about MORE gears and these D. C. trucks never really NEEDED more gears.

Hate to beat this horse, but a short while back there was much discussion about a magazine article about a tow contest between the D-Max, Ferd, and CTD. As I recall the D-Max was the winner, the Ford and Dodge lagging. It was a spirited discussion, and I believe the not unanimous conclusion was that the D-Max may have had an unfair advantage because of the extra gears. I'm not a racer, so I don't care.



I agree that four gears is all we really require , but a fifth gear would be nice.

 

[DPKetchum]

I don't think rear gearing was the same in all three. The V8s are FASTER period. But they don't (torque charts show it) build low end grunt like a inline does. Also their considered LIGHT DUTY diesel engines and the Cummins is a MEDIUM duty engine(based on hours at peak rpm between overhauls)

 

[steved]

My 06 Dmax turns about 1600 @ 65. Around town not towing I have no problem getting 16, overall its fuel economy is about the same as the 06 Dodge I had.

My buddy has a 05 Dmax and can get any more than 14mpg highway... he is sorta disappointed as he was getting 20 with his 91 CTD... he has 28k on it... any ideas?



He's really not happy since I get better than his truck, and I'm spinning 4. 10s.



steved

 

[brods]

The V8 diesels DON"T have the low end GRUNT the Cummin does. It really dosen't NEED a 6 speed trans. All the Ford Torgueshift does is SPLIT 1st and 2nd gear so it can get a load moving. The V8s have good power but in a HIGHER rpm range like a gas engine. All the going ons about MORE gears and these D. C. trucks never really NEEDED more gears.

Maybe, but with all that low end grunt it sure would be nice to have an extra top gear to turn less rpm at current highway speeds (70+ mph). And a lower first gear with the rest spread out so the torque converter can be tightened up some, would be nice too. If you think about it the 48RE is almost a 5 speed anyway, since the converter is so loose lockup acts like another gear. The downside is all the energy wasted by the torque converter (in the form of heat) until it locks up. That heat means shorter fluid and transmission life as well.



6 speeds sounds good to me! 68RFE Oo.

 

[steved]

I thought the new DMax's were a 6spd Ally???



steved

 

[COBRAJET]

More gears are always going to be better. There is a reason the manual is a 6 speed. Dodge is just a little behind, but will be there shortly in the automatic race for gears. The Dodge has more lowend torque but it is not that big of a difference to give up a gear or even two since the Torque shift behaves like a 6 speed and the Allison is. The PSD ratios are 3. 1/2. 2/1. 54/1. 0/. 71. The 48RE is 2. 45/1. 45/1. 0/. 68. The Allison is very close to the Fords with the 6th gear being a second OD at . 64. With the added HP and torque 350/650 of the new Dmax they felt another OD was a viable option for mileage. I would love another gear or two... spread them out like the competition for better acceleration empty or loaded and give me a deep overdrive for 75mph at 1600RPM and I would be happy. There are a ton of auto trannies now on the market with 6 and 7 gears now. There is a reason... I want gears.

 

[Foil Freak 1211]

I'd love to have a 7th gear in my manual. I towed the boat home today - 75 mph is almost 2500 RPMs in 6th with 4. 10.

 

[JUeckert]

cant speak for the duramax,but depending on years,and applications the 7. 3/6. 0 engines [mainly7. 3] could match or in some cases turn out more trq than a cummins. here again it depends on the application the engine is used in.

 

[Jong]

???

Not quite sure about that statement, but one thing I am sure of is the torque curve, or better yet plateau of the Cummins motor. A V8 diesel may produce a higher torque peak (usually at a higher RPM), but the Cummins produces about 90% of its peak torque right off idle. That is the main advantage the Cummins has always had over V8 diesels, in addition to less moving parts and lower necessary operating RPMs leading to better overall reliability.

 

[RVTRKN]

cant speak for the duramax,but depending on years,and applications the 7. 3/6. 0 engines [mainly7. 3] could match or in some cases turn out more trq than a cummins. here again it depends on the application the engine is used in.

Yes it is true, however the RPM's have to max out to overcome the V8 design causing overheating in extreme temps losing what is gained with the clutch fan on at all times pulling grades and especially with the DMAX which will overheat even with the clutch fan on. The test grade which is talked about in a early post was with a short grade at 60* ambient temp (by design, favored to GM). My cummins has never even been over 200* pulling 5ver all over the NW in 110* temps even in the grades at 65MPH (passing both brands along the way), and as the RPM goes in the V8's your MPG goes with it. I'm a Dodge man I'll admit but you cant beat a cummins in a light truck with a medium duty engine.

 

[COBRAJET]

Back in the 47RE days the Cummins was detuned quite a bit with the auto... . around 420lbft if memory serves me. The 6 speed got the real deal. My 01 and 03 were sticks because of this. The PSD's and Dmax's with auto's got the same motor as the sticks... 500lbft. I never had overheating issues with 3 Ford auto's... just less mileage empty or towing... 10-15%. The clutch fans only engaged on "big" hills just like my 06 Cummins which will climb to 210-215 according to the gauge and the Edge monitor which is nothing but a duplicate of the factory gauge.

 

[MCrossley]

I was at a horseman's bbq yesterday talking with a lady who has a d-mac and she was telling me how her beloved d-max gets 14mpg at 65 and she has had it in the shop for the last month trying to figure out why the thing would just die for no reason at a light; she loves the truck but drove a buddy's megacab for the duration of the repair and well she is selling the d-max she said it pulls her trailer better overall not in every way but overall and she said it is actually quieter than her d-max under load so I thought that was a pretty fair analysys since you she likes her chevy and was being honest.

 

[jjdiesel]

Yes it is true, however the RPM's have to max out to overcome the V8 design causing overheating in extreme temps losing what is gained with the clutch fan on at all times pulling grades and especially with the DMAX which will overheat even with the clutch fan on. The test grade which is talked about in a early post was with a short grade at 60* ambient temp (by design, favored to GM). My cummins has never even been over 200* pulling 5ver all over the NW in 110* temps even in the grades at 65MPH (passing both brands along the way), and as the RPM goes in the V8's your MPG goes with it. I'm a Dodge man I'll admit but you cant beat a cummins in a light truck with a medium duty engine.

Well stated!!

 

[JUeckert]

like i said i cant speak for the duramax,other than the fact that i have three different connections who have and happily own them. one man was a hot shotter who hauled boats as well as steel castings all over the country,only [major]repairs i recall in a nearly 500k odo reading was one ally,and 3 injectors. the guy replaced it with a 06 dodge rigged exactly the same way and his biggest complaint after 20k miles is the fuel mileage and claims it here recently may have a bad injector. i'am by no means a duramax fan,the aluminum heads being the biggest reason as to why. however as i first posted on the v8 not being able to match a cummins in low end trq,thats a misconception. futher more ,there is no free ride with any of these trucks when it comes to doing work at low rpm 's. put the same drivetrain specs in all of them,and they will turn similar rpm's at any given speed. the only way one is going to turn less rpm's than another is to have a difference in gearing,or driven speed[mph].

 

[JasonCzerak]

I'd love to have a 7th gear in my manual. I towed the boat home today - 75 mph is almost 2500 RPMs in 6th with 4. 10.

When I first got my truck, there were PLENTY of times I went for the "7th" gear.

 

[steved]

When I first got my truck, there were PLENTY of times I went for the "7th" gear.

After 86k, I still try for 7th and eighth sometimes... :-laf



I sometimes get confused and think I'm in 4th when I'm actually in 6th... and then I realize there isn't an extra slot between "3rd" and reverse...



All this, then I drive my dad's 5spd every blue moon... then I'm almost completely lost... no 6th?! Your 1st is in the wrong spot... so is your reverse!! :-laf



steved

 

[JasonCzerak]

After 86k, I still try for 7th and eighth sometimes... :-laf



I sometimes get confused and think I'm in 4th when I'm actually in 6th... and then I realize there isn't an extra slot between "3rd" and reverse...



All this, then I drive my dad's 5spd every blue moon... then I'm almost completely lost... no 6th?! Your 1st is in the wrong spot... so is your reverse!! :-laf



steved

kinda like getting into an automatic and looking for the clutch while putting your foot though the floor.