Auto Trans shifting...

[SStandley]

Guys.



I just purchased a 2006 Dodge Ram 2500 Cummins 4x4 with the auto trans. It has about 1500 miles on it and I have noticed that when applying the gas (sorry diesel) pedal especially from a stop light behind a grandma that thinks you should take 1 mile to accelerate to 35mph.



The unloaded truck revs to 1500 rpm and goes from 1st-2nd with a hard shift then immediately from 2nd to 3rd with a softer but noticeable shift.



If I am pushing it through the 1500rpm range the effect is not noticed. It is also not noticed coming back down (of course autos don't downshift through the gears in coast). Should this be happening or is it because I am dwelling to long in the rpm range?



Anyone know what the shift points (rpm) are?





This is my first Diesel truck and am getting used to all the sounds and such of the vehicle.





Thanks for you help, steven

 

[HBarlow]

Steven,



My current truck is my first experience with the Dodge automatic and I'm still trying to understand it myself after almost 30k miles. The primary answer to your question is this: nothing is wrong with your transmission and nothing is likely to become wrong with it. Many may disagree but in my opinion it is a crude and awkward but tough and reliable device which is probably almost bullet proof under hard towing with good maintenance. The 48RE is basically the same old Torqueflight automatic developed to operate behind small and modestly powered V8 gas engines in the 1950s and upgraded to handle repeated drag racing competition behind the awesome high performance big block MOPAR V8s of the 1960s. It has an overdrive 4th gear now and a locking torque convertor and is managed by complex computer programming but is the same crude old automatic. Lots of things are going on with it. It is shifting then locking then shifting again and I'm not always sure what gear it is in or whether the torque convertor is locked or not. In time you'll understand better because under throttle if the convertor is not locked it seems to make a lot of noise and churn a lot of fluid but doesn't accelerate very much. When the convertor locks it lurches forward with enthusiasm. I find it not to be a very pleasurable automatic transmission for the driver but all indications are it will pull heavy trailers for several hundred thousand miles without rebuild.



Drive it and don't worry. It will be fine.



Harvey

 

[Suprmn]

I agree. I have several dodge diesels with automatics and currently have the 48RE. All of them seem to shift inconsistently and erratic at times. I have never found the trick for making it shift good every time and when I take it to the dealer they just say that is working correctly.

 

[KSHall]

My 05 does the same thing. It got real bad once when it would shift from 1st to 3rd then back to 2nd and then who knows what gear . The guys at Courts Motors installed a couple of sensors and a governor solenoid and has so far made it ton better, not what I would call right but the best it has been so far. It's got 22000 in the ticker.

 

[HBarlow]

The biggest disappointment or frustration for me is that it is a difficult transmission to drive smoothly or with skill. Sometimes if I want it to hold the current gear and accelerate it will slam the next gear or lock the convertor and lurch forward. Other times under heavy throttle it will smoothly but firmly upshift. If I simply put my foot in it the transmission will shift through the gears and lock the convertor according to some plan of its own. I find it very difficult to impossible to control shift points with my right foot if I want to "drive" it. I can't figure out if the computer programming logic is simply different than mine or if it is such an awkward device that is doesn't coordinate very well with the operating characteristics of the Cummins engine.



The PCM does do a good job of coordinating the engine, transmission, and Jake brake for deceleration and I do appreciate that so I guess I'll just accept the truck as it is and not worry about it. I talked to lots of transporters with high mileage Dodges, most with the 47RE. All told me that they were getting good service from the transmission and I heard figures like 400k miles before overhaul.



Harvey

 

[SStandley]

Thanks for the repplies guys...





It is doing good and I hope that I get 400K before rebuild... Just did that on a 150K DR1500.





I will keep going and keep a squinted eye on it.



Thanks again,Steven

 

[GaryCarter]

I agree the programming is not the best. That said, part of the issue here is the limited RPM range for the Cummins combined with just 4 gears. If you've ever driven a heavy commercial vehicle with a four or five speed Allison, it's sort of similar.



Notice that the other truck makers are going toward diesels with higher revs plus more gear options to smooth the transitions.



Personally, I hope for a Cummins six with a six speed auto some day...

Gary

 

[DOWG]

I am continually surprised with the performance versus cost of the Superchips Flashpaq. I drove a 1998 12 Valve with the 47RE and DTT, etc, modifications for 250,000 miles. Bullet proof transmission, mine was set up for firm (hard) shifts.



Anyway, the new 48RE in my 2006 megacab was a huge improvement over the 47RE. Superchips Flashpaq made a futher noticeable difference in how the 48RE shifted on a "driveability" basis.



I did not want a huge HP increase, just enough to make it fun (65 HP), which combined with the firmer shifting points, for a couple hundred bucks was pretty easy on the metaphysical, mechanical and monetary side of things.



I do not mean to suggest, my satisfaction with Superchips is the low cost. I am just pleasantly surprised it works so well, for so little money and no problems.

 

[PGreenleaf]

What is a superchip, and what does it do.

 

[CPG]

Seem to agree with most on this about the roughness of the 48RE transmission. My old "93" with the 37Rh or 518 seemed to be much more smooth and consistent. At 20K Ive already had it serviced but it remains the same. Its a heavy duty trans. and have to find the faults in inconsistent shifting due to the computor set/up on these trucks. Feather footing the throttle seems to not make much difference. As I mostly use this in hauling my trailer, it seems to do well. My advice is to "drive it ". Have not heard of many failures with the 48RE.

 

[Latenight6]

mine did the same thing wound up bein a vavle body

 

[TexBamBam]

Mine really does weard things witht the 37" tires changing the gear ratio... . need to chip this baby... but then what chip does it all... I guess if you stack 5 of them it would do it all... but hey. Which five to stack???

 

[tgrfan2]

mine did the same thing wound up bein a vavle body

Did yours show a code? The dealer checked mine for codes while in for the recalls. Nothing showed up. My friend's 03 HO 48re shifts much better than this 06 for sure. Tow/Haul is a joke on the 3-2 downshift. I have gone back to driving it with OD off and manually shifting to 2nd as it will try to stay in 3rd even below 30mph in T/H mode at light to moderate throttle.

 

[SSteffen]

Has anyone tried stacking the SuperChips programmer? It is supposed to allow to program your own shift points, I haven't tried it but i am surly thinking about it. I do get very irritated with shifting as well

 

[TexBamBam]

Someone needs to develope a fuel mileage and trans box... for cheep.