Tell me good/bad on a 2003 Cummins with auto trans

Looking to buy a 2003 Cummins 4x4 auto. 180,000 miles. Well taken care of clean truck.

I would use it for general truck use and hauling cars on open trailer. Max 2500 miles a year. I won’t use it for daily driving.
What can you tell me about these trucks. Don’t tell me to buy a hemi truck, not going there.
When does any trans problems show up?
When do they need fuel system or injector work
Anything’s to Look out for or problems they have. Thanks!

The automatics work hard until pushed too hard.

Look for one with a manual transmission and do not tow in overdrive, ever.

Is it a 2003 or 2003.5?

The 2003.5 has the 48RE, that trans is pretty good if maintained.
The biggest issue is keeping the front band adjusted. Let it get away from you and you will ruin the front drum and smoke the front clutch.

Don’t use anything but ATF + 4 in it. I’ve seen hundreds of 250K plus mile units in the Reman program, nothing wrong with them except that front band and drum.

Trans issues can happen anytime. If it has not been done yet, plan on a rebuild using better frictions, shift kit and a billet converter with a lower stall. Getting the trans redone with the low stall converter really gains some power to the wheels as it cuts way down on slippage and heat which kills the trans and loses efficiency. Injectors can need replacing anytime past 100k. Depends on how clean the system was kept and whose filters got used for replacement. Cummins had one that went down to 7 micron which replaced the oe 10 micron unit. I think Baldwin had one that went a little finer. Fuel cleanliness is a big issue on the common rail systems. Has the lift pump been replaced and/or upgraded to the in tank unit like what's used on 05 and later? Depending on power output sought, you can run that or an Airdog or FASS unit which can give you better filtration too. If you replace the injectors, do not use remans. Only new BOSCH or BBI units. New BOSCH can be had from injectors direct.com. You will need the feed tubes too as they have little filters inside them. BBI makes a really good unit if you plan on upping the power but they are not emissions legal. BOSCH does make a 50hp new unit which is what I have in my 04.5 truck. Different spray pattern from yours due to piston design. If you check out cumminsforum.com or the Turbo Diesel Registry, you'll find a wealth of info for the truck. TDR has a quarterly publication you can get a subscription to which is the bomb for information about the trucks. Only deals with Dodge/Cummins from 89 on. No fluff, just great info and no bs to make advertisers happy.

As t-man said…. 48RE mucho better…. and his advice spot on. IIRC the 47RE early builds still had the data plates on the timing cover, the newer it was a white decal on the valve cover.

I’d be very surprised if it still had the “walker pump” on it…. The OE lift pump was attached to the back of the fuel filter housing. I used to grab a small hammer to perform “cpr” on them when they’d come in on the hook as they’d fail often. Didn’t hurt anything in my experience, but obviously aggravating when it occurred (no start/eng dies). Around 05 they came stock with the lift pump in the tank and “retrofit kits” were made available for the older trucks and most I see anymore have been “upgraded”. If it hasn’t been upgraded I’d be carrying one under the seat

A/C will always be a few degrees cooler on drivers side…. Nature of the beast. Temp gets too different from side to side = low charge.

Injector life…. Sure swapped alot of sets around the 180-225k mark. If you free rev it and it comes down to idle nice and smooth that’s a good thing. Rev it and it hangs at rpm and tumbles back to idle unevenly that’s a sign of things to come. I’m not a huge “additive” fan, but I’ve seen CRC DIESEL FUEL THERAPY do some pretty amazing things.

Why not tow in OD? I tow EVERYWHERE in OD with my 47RE. Of course we’re only 18,600ish combined. Hauls quite well considering my 3.55 gearing

Mfg date 6-03 on the door sticker. The lift pump has been changed. It now has a unit under the fuel filler neck.

Looks like front cover on engine is leaking down low and has oil on the crank sensor and steering box. No dripping where it parks, just damp. Looks like the fan is blowing the oil around. The power steering is full and th cap has oil residue so it hasn’t been off in a long time. The PS fluid stinks.

The ATF is red and smells good, some black came off the stick on the white towel. Pan is barely damp and dirty, hasn’t been off recently,

my 2003 never had transmission problems after i upgraded to BD Diesel Converter- Valve body with pressure loc. Deep pan. Pulled 28ft enclosed no problem in overdrive. Now i did have the bottom of the Axle rot out and had to replace it but got the better 3.73 gear, bed sides had to be replaced typical rust through, and rack and pinion but that is about all in 150000 miles.

Just don't let me drive it, no more 48RE's for me! LOL Be sure to change the injectors around 200K miles and get some good ones! Biggest issues with the common rail are the injectors, killed two of them one when an injector went wide open and hydraulic'd the engine and another when one went dead and burned a piston. Both had around 250K on them...

I have 2003 non HO. Did injectors at about 220,000 miles. Upgraded to FASS pump and filters at that time because I don't want to buy injectors again. Keep an eye on the trans temp. I added a deep trans pan as well. If you don't have gauges, then get some or an Edge or something that lets you see what's happening. Nothing wrong with watching your EGT either. The dash will crack if it isn't already. There is an airbag recall and some have a front end recall.

The late 2003 HO cummins has more power, so that would be a plus. Its easy to make these engines make a lot of power, but then you start breaking stuff, starting with the trans. And the "bulletproof" trans is $$ unless you built it yourself. Its been a good truck and I've got about 270,000 miles on it now.

Look at the front band adjustment stud. If it is even with the locknut then the band is on its last leg. Could be fine for a long time but keep an eye out for 2-3 flare.
If it starts doing that I would drop the trans and re-clutch it with new front band.

As for hauling, you mention hauling cars. More than one at a time? If no, the production converter is fine. The 48RE has more controller logic than the 47, it is capable of going in to lockup in 2,3, and 4th based on temperature of the trans fluid. The Mopar Reman converters have improved stators and stator clutch components not found in other Remans.

Single car open trailer 3800-4500 lb cars.

So is this 6-2003 production date going to be the better equipment as mentioned on some prior posts?

Here is a pic of the band adjuster, shows 3 threads above the nut, trans works great on a test drive.

Free rev the engine and it returns to idle smoothly.

PRNDL switch leaking through connector…. Eventually rots wires. See that happening already

A truck 18 years old and 180K on the clock. Grow some big ones and buy it and be prepared to suck it up when it fails. Its always a mixed bag.

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Gee thanks for your help mr cocky!

I never owned one or been around one so I’m asking questions. I’ve learned a lot From this thread, but not from you. I’ not scared just want to be informed if that’s OK with you.

I personally liked the 305 555 common rail, seemed to get the best fuel mileage and towing an open trailer you won't even need to take it out of OD...

The 8th position in the VIN code should be a "C" or a "6"
"C" = HO
"6" = SO / HP depends on a Fed or California truck.

2003 S.O. Federal Emissions: 250HP/460lb.ft. Available with NV4500 or 47RE
2003 S.O. Calif. Emissions: 235HP/460lb.ft. Available with NV4500 or 47RE
2003 H.O. Federal Emissions: 305HP/555lb.ft. Only available with NV5600
2003.5 The 47RE was replaced by the 48RE automatic transmission and available with the H.O.

Post a pic of the pan rail that shows the PK number - that’s the best way to figure out what you have - 47 or 48.

Band adjuster doesn’t look too bad so I think you are ok in the respect.

Throw the last 8 of the vin up I could tell a ton

The valve cover sticker is white and it says 305 horsepower. 6-18-2003

Last 6 of VIN 850585. 8th digit is C

Trans looks like PK52854003AA but those dots are tricky to read.

The A/C is chilly on the drivers side and cool on the pass side.

Good info so far, thanks guys!

A search found this,

https://ptsreman.net/products/2003-dodge-pickup-3500-5-9l-4wd-52854003aa-ps360-5675

So it is the 48RE trans which is a good thing.

Does the torque converter have a drain plug in it?

No drain plug in production.

I have a 2003 with 48Re and have towed 11K with it for 11 years now. The injectors are weak on the Cummins engine that year. I had to replace mine at 100K miles. Water pump started leaking around the same time. Other than that the engine has been fine. I put the servos and a goerend valve body in the trans and as long as I am easy on it I can run it with a 75hp tune without slipping. The torque converter is the weak link imo. Plan on replacing it here soon.

'03.5 w/48re here with 230k. Keep up on the fluid changes (inc diffs), replace lift pump, keep band, ... etc. Regular check and fix Stuff. Might mention the ac blend door. Sometimes the plastic breaks and diverter will blow hot air. Either need to remove the dash, or now there is a fix. I peruse turbodieselregister.com on occasion good site.
Regarding the 48re operation.
It has a lock-up torque convertor. Lock it out when towing on anything but downhill or flat with tailwind. Always strive for under 2,700 rpm for longevity and economy, when you hit a hill towing, drop her back to 45 and into 2nd and stick in the truck lane. Hi RPM and heavy loads is the killer.
Do get the deep trans pan and good temp gauge on it. I mounted ours down by the transfer case shift Used a spray paint can for a cup and just jammed it there, friction holds it and it's eary to train the brain to look at the trans to niote the temp.

I have an 05 with the 48RE. Original transmission went 250,000 miles, and wasn't bad when I had it rebuilt (put a triple disc converter and a billet input shaft in). I have been pulling a 24ft box trailer from Seattle to Phoenix and have no issues (and never had) towing in overdrive. I now have 282,000+ and am still on the original injectors. I have the oil sampled at most oil changes and have never had any issues. The A/C is another story, still working on it.

I have an '04 with 311,000 miles on it. I bought it in a similar position that you are wanting to use it for. Low miles per year, use it as a truck when needed, but not a daily. The trans was rebuilt around 280,000 or so, and the injectors were replaced then as well.
Other than that work, there have been occasional electrical gremlins that have never left me stranded, but are annoying. My truck is a 1 ton dually 4x4 with a dump bed on it. If I take it out of OD when towing, i can only go about 60 mph before the rpm's are singing- so once im up to speed, i switch back into OD to maintain 70 mph. I dont see a problem with that, and it has not been a problem.

I think this generation of truck is an acceptable vehicle for what you are planning for it. It is also relatively easy to work on and get parts for.

Last 6 of VIN is 850585 what can you tell me about it?

Something like this kit to mount a CAT fuel filter will help tremendously with injector life. Cat filters down to 2 microns.

https://www.dieselfuelfilterkits.com/03_12_cummins_fuel_filter_kit.html

Kevin

Fumble fingered 6 instead of 8….. corrected too late. Basically I could pull up the build data.

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It has an electric lift pump and two filters mounted under the fuel filler area. I haven’t been under there to see the name or numbers on it yet. Pump runs with key on engine off, it is fairly quiet.
I saw a different for sale truck with that CAT dual filter set on it.

Last 8 digits of VIN are 3G850585.

07 here. 326k, trans serviced religiously. I have no threads showing after the last band adjustment. Just finished hauling my 52 Dodge Down from WA state. Had a injector service done before my trip. The thing ran like a new truck. I got an average 16mpg going up and 15 mpg coming back. That has never happened.usualaverage was 13 mpg. With the miles on those injectors I really keep an eye on the EGTs.

As said above, the difference in AC temp is a blend door issue. The dealer fix is to remove the dash and replace parts - and $$$. Good issue to raise when trying to negotiate a good deal. If interested, there is a cheaper fix you can read about here: https://heatertreater.net/dodge-ram-02-08

3.73 gear, 48RE (yeah we figured that out already), trailer tow, 34gal tank, dual zone temp (failure prone, done a lot of door kits. Door kits come with revised part to take load off door stop), steering wheel radio controls (don’t laugh… I had a friend that drove his like a year before I brought that up , HD snow plow prep group, HD eng cooling,

Thanks for the help and info everyone!

What is different on the snow plow prep group? This truck was sold new about an hour from the Canuck border.

Not sure about 3rd gens, on 2nd gens the upgrade was a 5200 lb axle vs. the standard 4800 or 4850, can't remember which. IIRC, the smaller one was at or near capacity without adding anything.

very interesting post.
i miss my 1996 3500 x cab 12 valve P pump auto dually! maybe the best, trouble free, dependable workhorse truck ive ever owned.