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Discussion Starter · #1 ·
Hi everyone. I just picked up a 2003 2500 Cummins. Truck was first sold in Idaho. After some years there it went to Washington. And now to Cali.
Best I can tell is that it is a standard output engine.
Tranny is a 47re and the clock is showing 204k which I believe is accurate.
I owned a Duramax prior to this truck and thought it was the best thing ever. Until I drove this dodge.
Wish I would have bought one sooner.
Anyhow was hoping that some one could help me out
The truck is 100% stock with the exception of the flatbed that the previous owner put on.
Best I can tell the HP is a paltry 230hp.
Far cry from what it needs to be.
It runs like a top but won't get out of its own way.
The truck struggles to pull
An empty trailer that weighs about 4700lbs up a hill that would barely affect my old truck.
Even with that I love this truck.
I guess my question is is this normal?
I know 230hp is low but I figured it should do better.
I haven't had a chance to check compression or fuel pressures bit when checking for blowby it show absolutely ZERO blowby. I would expect a little at the filler cap but it shows none.
Can someone tell me if this is how they run when stock? Remember she's only cranking out 230hp.
 

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California (carb) trucks 2003-2004.0 were 235 hp.
Yup, there dogs stock. I had one.
Unfortunately the thing holding you back the most is the 47re. Beef that up first is what I'd do, then add a smarty Jr.
It brings the 235 rating up to the standard 305 rating. From there you can opt to add power on top of the 305 if it's not enough.
 
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Discussion Starter · #3 ·
California (carb) trucks 2003-2004.0 were 235 hp.
Yup, there dogs stock. I had one.
Unfortunately the thing holding you back the most is the 47re. Beef that up first is what I'd do, then add a smarty Jr.
It brings the 235 rating up to the standard 305 rating. From there you can opt to add power on top of the 305 if it's not enough.
Previous owner had a shop do some work to the tranny. He mentioned things like machining something to add more clutch discs and changing the shafts and stuff.
He admittingly didn't know anything about trucks but he did pay the bill for the tranny work.
Can you tell me more about the smarty? Is this the MM3 tuner?
I plan on upgrading the tranny to a 6 speed Allison. Just waiting on ATS to release the 2003 kit.
If for any reason that doesn't work out can I just upgrade to the 48re? If so is it a plug and play swap?
 

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I'm sure someone will chime in that has more experience with transmission swaps than me.
But my understanding is that a 47 to 48 swap is not a hard thing to do.
Google smarty Jr. 30, 70, 100 horse options, minimal smoke, great tuner for the beginning enthusiast. Very popular tuner with guys who know the Cummins well.
Mm3, hp tuners are more refined options for when you want to fine- tune your truck. But they are expensive.
Correctly built 48s are a very stout and well- performing transmission.
 
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Discussion Starter · #5 ·
One more thing. The tag on the engine says ISB250 or 255 can't remember which now.
Someone told me that this represents HP ratings. Does this nu.ber mean anything?
 

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Discussion Starter · #7 ·
One more thing. The tag on the engine says ISB250 or 255 can't remember which now.
Someone told me that this represents HP ratings. Does this nu.ber mean anything?
That year had 3 ratings: [email protected]
[email protected] and HO @305. Both of the SO motors are the same, meaning no piston gallery cooling, 10.25 rear end, etc.
Thanks for the info.
Have to be honest. The smaller rear end kinda bums me out more than the fact that my truck is only pushing 250hp.
In time I will deal with all of it
My tentative plans are to go with a firepunk 48re towmaster with the mm3 tuner.
If I can find a 11.5" rear end at a reasonable price I will get it as well
 
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I wish you well with the new truck.

For your 18 year old 2003 truck, who knows what engine and trans are in it.
Or what parts are in the engine or in the trans.

The trans could already be upgraded with full 48RE parts or already with full aftermarket parts.

Don't worry about the SO engine rating. It's super easy to bump that up.
You will have other issues to address 1st!
 

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Discussion Starter · #9 · (Edited)
I wish you well with the new truck.

For your 18 year old 2003 truck, who knows what engine and trans are in it.
Or what parts are in the engine or in the trans.

The trans could already be upgraded with full 48RE parts or already with full aftermarket parts.

Don't worry about the SO engine rating. It's super easy to bump that up.
You will have other issues to address 1st!
Other issues? The engine is bone stock.
I bought the rig from a farmer whos knowledge of trucks was where to put the key and how to fuel it up.
He said he replaced the tranny 2 times and finally had a shop rebuild it. He said they added new shafts and clutch discs but didn't fully understand all the lingo of what was done.
What I took away from it was that the applied pistons were machined to add clutch discs to the packs and that maybe the input and output shafts were replaced with billet shafts etc
 

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Other issues? The engine is bone stock.
I bought the rig from a farmer whos knowledge of trucks was where to put the key and how to fuel it up.
He said he replaced the tranny 2 times and finally had a shop rebuild it. He said they added new shafts and clutch discs but didn't fully understand all the lingo of what was done.
What I took away from it was that the applied pistons were machined to add clutch discs to the packs and that maybe the input and output shafts were replaced with billet shafts etc
I take it that what was done to the tranny as: billet input and/or output shafts, I would guess a new valve body as that is a pretty standard upgrade, and finally a new torque converter ( what stage 1, 2, 3, etc. who knows).These are pretty standard upgrades to the 47re and they give you horsepower breathing room on the tranny depending on who made the parts, I did the same thing (suncoast transmission) to my 03 47re, it gave me about up to 600 hp breathing room. The question to ask the farmer is what shop he took it to and then call them up. They will have the records of the work done and who's parts they put in
 

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Discussion Starter · #11 ·
I take it that what was done to the tranny as: billet input and/or output shafts, I would guess a new valve body as that is a pretty standard upgrade, and finally a new torque converter ( what stage 1, 2, 3, etc. who knows).These are pretty standard upgrades to the 47re and they give you horsepower breathing room on the tranny depending on who made the parts, I did the same thing (suncoast transmission) to my 03 47re, it gave me about up to 600 hp breathing room. The question to ask the farmer is what shop he took it to and then call them up. They will have the records of the work done and who's parts they put in
Great advice. I will do that.
I just ordered an 11.5" rear end cause the 10.5 was starting to howl a bit. I will get the shop info and see what that yields me.
Then onto an mm3 or smarty.
 

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Great advice. I will do that.
I just ordered an 11.5" rear end cause the 10.5 was starting to howl a bit. I will get the shop info and see what that yields me.
Then onto an mm3 or smarty.
Before you go swapping rear ends, check the fluid level and condition in the transfer case, should be bright red and clear. If you're 2wd then disregard that, but more times than not an under-filled transfer case or stretched chain will cause a real noisy howl in the cab.

After that do a fluid change in your rear end (and front too if 4x4). If there's glittery oil in either one then that's a solid indicator. If you got the 2pc driveshaft with the crappy AAM hanger bearing, those things like to howl right out the box. The 10.5 is not a weak axle, just an improved 14 bolt. I'd be more interested in narrowing down the howl rather than throwing (expensive) parts at it
 
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Discussion Starter · #13 ·
Before you go swapping rear ends, check the fluid level and condition in the transfer case, should be bright red and clear. If you're 2wd then disregard that, but more times than not an under-filled transfer case or stretched chain will cause a real noisy howl in the cab.

After that do a fluid change in your rear end (and front too if 4x4). If there's glittery oil in either one then that's a solid indicator. If you got the 2pc driveshaft with the crappy AAM hanger bearing, those things like to howl right out the box. The 10.5 is not a weak axle, just an improved 14 bolt. I'd be more interested in narrowing down the howl rather than throwing (expensive) parts at it
More great advice.
Do you know what oil the t case takes? What about the gear oil?
 

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Great advice. I will do that.
I just ordered an 11.5" rear end cause the 10.5 was starting to howl a bit. I will get the shop info and see what that yields me.
Then onto an mm3 or smarty.

When it comes to the 47re (This is my opinion so if yours is different that is fine) its greatest strength is also its greatest weakness: It is essentially a mechanical speed transmission with an "aftermarket" overdrive attached to it with some minor external electronic sensors and controls on it. While it does not have all the flash (ie smoothness) an Allison or a 68re and on up have when it comes to gearing and components it is a simple tranny that I can take to any backwoods tranny shop and they will repair it not only quickly but cheaply. Sure to handle huge numbers (800+ HP) It needs to be completely redone, but for the average owner with those previously mentioned upgrades it will be just fine. The transmission shop I live by took the tranny out rebuilt it with the afore mentioned parts and and reinstalled it in less than a work day. They are that simple and easy. The one major upgrade needed besides what is mentioned is an auto-loc or similar controller to lock up the torque converter for when you are hauling loads uphill and when/if you have an exhaust brake. I see that the 47re gets a lot of hate which I don't get. Anyways off my soap box and back to work....
 

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Discussion Starter · #15 ·
When it comes to the 47re (This is my opinion so if yours is different that is fine) its greatest strength is also its greatest weakness: It is essentially a mechanical speed transmission with an "aftermarket" overdrive attached to it with some minor external electronic sensors and controls on it. While it does not have all the flash (ie smoothness) an Allison or a 68re and on up have when it comes to gearing and components it is a simple tranny that I can take to any backwoods tranny shop and they will repair it not only quickly but cheaply. Sure to handle huge numbers (800+ HP) It needs to be completely redone, but for the average owner with those previously mentioned upgrades it will be just fine. The transmission shop I live by took the tranny out rebuilt it with the afore mentioned parts and and reinstalled it in less than a work day. They are that simple and easy. The one major upgrade needed besides what is mentioned is an auto-loc or similar controller to lock up the torque converter for when you are hauling loads uphill and when/if you have an exhaust brake. I see that the 47re gets a lot of hate which I don't get. Anyways off my soap box and back to work....
While I have zero experience with the 47/48 slush box I have heard and read good things when built.
Simple is good too.
I would love to do the Allison swap but $7500+ the Allison is a grip of money. I would all but do that swap buty worries are what if the companies that provide the electronics are out of business I. Ten years. Could be a problem.
Anyhow I will likely just buy the Firepunk 48re and get a tune with something that offers tranny tuning as well.
Thanks again for the great info.
 

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Lift pump may be weak. Cheap to replace with new. Change fuel filter & air filter as well.

HP isn鈥檛 a problem with these trucks, that鈥檚 a child鈥檚 鈥減roblem鈥. Making SURE everything is operating CORRECTLY is what matters.

鈥淟ow power鈥 is also:

Brake Drag?
Alignment (and tire pressure)?
Charge Air Cooling system leaks?
Wrong tire size and type?
Exhaust pipe collapse?

Do these simpler things as you do ALL service requirements

Valve lash done?
Harmonic balancer failing?
Motor mounts disintegrated?
Leaf bushings rotted?
Shocks more than 60k?
Front sway bar bushings replaced?
Steering not updated (4WD) to MY-2008?
CP-3 tested?

This is all stuff you would have to get to anyway.
Save trans till later.

Start an account on FUELLY, Record EVERY SINGLE GALLON used.
Record engine hours at same time.

Average MPH and Average MPG are how to play the game.
Adjust DRIVER to truck. NOT the reverse.
It鈥檚 all about being smooth

Or go back to rice burners.
 

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Discussion Starter · #17 ·
Lift pump may be weak. Cheap to replace with new. Change fuel filter & air filter as well.

HP isn鈥檛 a problem with these trucks, that鈥檚 a child鈥檚 鈥減roblem鈥. Making SURE everything is operating CORRECTLY is what matters.

鈥淟ow power鈥 is also:

Brake Drag?
Alignment (and tire pressure)?
Charge Air Cooling system leaks?
Wrong tire size and type?
Exhaust pipe collapse?

Do these simpler things as you do ALL service requirements

Valve lash done?
Harmonic balancer failing?
Motor mounts disintegrated?
Leaf bushings rotted?
Shocks more than 60k?
Front sway bar bushings replaced?
Steering not updated (4WD) to MY-2008?
CP-3 tested?

This is all stuff you would have to get to anyway.
Save trans till later.

Start an account on FUELLY, Record EVERY SINGLE GALLON used.
Record engine hours at same time.

Average MPH and Average MPG are how to play the game.
Adjust DRIVER to truck. NOT the reverse.
It鈥檚 all about being smooth

Or go back to rice burners.
First thing I did was replace the lift pump with a fass. New air filter as well.
Helped less than I thought it would as the original air filter was one of the dirtiest that I have seen. Fuel filter was equally dirty.
Not sure if you missed it or not but my engine is the ISB 250. She purrs like a kitten but lacks power big-time. My former truck pulled with authority at a rating of 300hp.
I will do the tranny upgrade and either the mm3 tunes or an EFI live tune. I'm sure this will fix the lagging power
 

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More great advice.
Do you know what oil the t case takes? What about the gear oil?
T case takes atf+4, same as the trans. I run whatever cheap 80w90 I can get my hands on in my axles, but I'm sure that's probably not correct, IIRC the manual calls for 75w90 synthetic. My axles have 390k miles on them and the front pinion is just now starting to growl, but it leaked previously and lord only knows how many underfilled miles it saw.

The 47re is not a bad trans, and it sounds like yours has had the usual reliability upgrades done. I'd try to get in contact with that shop and figure out what you got first. You may have a 400hp ready unit in there. Most important thing on any 47/48 no matter how built they are is keeping them cool. Unless you see any sub-zero temperatures then get rid of the heat exchanger and get the biggest external cooler you can fit behind the grille. You likely have a lot of life left in that trans.
 

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either the mm3 tunes or an EFI live tune. I'm sure this will fix the lagging power
No EFI for 2003, if you're just after a bump in power a Smarty jr or Smarty S06 will easily do so without any issues or hassles.
 
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