I have an 03 HD 4X4 and I am having a hell of a time getting the right HP numbers on the engine. Some say look at the engine data plate and it says it is an ISB 250 but is that the engine class or the horsepower output. I had the dealer plug the VIN into Chryslers site and the build sheet says the numbers are 305/555, just trying to get in the ball park cuz I pull a 38 ft Cypress 5er and want to have sufficient power, if I need to do some adds other than the Banks intake, 4" turbo back no cat and FASS, am thinking Smarty 6 with a Jasper and triple billet or just a better converter and a valve body.

 

ISB 250 means that you have the 250hp/465lbft standard output engine. How much does that Cypress weigh?

 

Cypress weight is 14,400 dry, GWR is 16,600 have pulled it all over the west coast since I got it and have had no problems with the truck at all.

 

Don't be confused by all the go fast parts you will see around here and think you need to put them on a truck that is a dedicated work truck. The more go fast/big power parts you put on, the more you will stress the vehicle and risk breaking stuff while on the road. That being said, you seem aware of that as you are concerned about the transmission needing upgraded.

It sounds like you've already pulled your 5er with the truck and its done well? Are you wanting it to do more, or have you not pulled it with this truck yet?

A Smarty will get the HP level of the truck up, you have an exhaust so the truck should basically be ready for it. Since you pull a load with the truck, you will want to invest in at least a Pyro and probably a real trans temp gauge so you can keep track of things when you start adding power over the stock design limits.

Keeping the smarty on lower power settings while towing will make sure it stays happy longer. The trick is to add enough power to tow safely, but not going overboard . . . going overboard requires a lot more parts.

On a tow vehilce, an upgraded transmission is never a bad thing. Its not a necessity, but it does make for good peace of mind. The transmission is technically a wearable item, so they will need rebuilt after they get some miles on them (like over 150-200k typically). Most just wait till the stocker gets tired and then upgrade when they rebuild. Just keep an eye on tranny temps and let off the throttle a little at gear changes to let it engage the next gear and then throttle back in is always a good recipe to make a stocker last long.

Simple mods like a valve body/shift kit will also go a long way to making things last but don't expect them to make the transmission operate like its been "built". VB mods are not a replacement for upgraded internals, increased clutch count, and a built converter.

 

Thanks for your input Route66Diesel, yes I have and intend to continue pulling the 5er with this truck. The only noticed wear when I had the tranny serviced was some clutch powder on the filter, tech said to keep a watch on it. Do you have any input on the hp output for the '03 ISB 250 model, I read online that there were two output ratings for the '03-'04 models the California model was the 250 hp while the other model was the 305 hp.

 

If the engine plate says ISB 250, i would have to guess that is actually what it is, the SO engine which is rated at 250HP. The engine plate on my '03 HO specifically said 305/555.

There are a few small changes to the motor internals (mostly piston oil cooling related), but 99% of the parts are the same between the 250 and the 305. The big difference is in the programming in the computer, so a Smarty will bring your power levels on par with the HO motors.

Regarding the clutch bits in the transmission . . .never a good thing, but the damage has been done. There are a few things you can do to help stop the damage and extend the life . . . and in a worse case scenario, they are good upgrades which can be transferred to the new trans if you ever have to upgrade.

If you have a "C" in the 8th vin number location you have a 48RE, a "6" in the 8th vin location is a 47RE . . . just so you know. A "Shift improver kit" (typically run $70ish, if you want more info shoot me a PM) is available for either transmission to help increase the pressure and decrease the slip time to keep everything happy (a definite must if you plan running more HP).

My #1 goal in setting trucks up is to retain the driveability and reliability when looking at upgrades. More HP is easy to achieve w/a quick tune, but the transmission is generally the 1st weak link in the system. Simply adding HP w/o adding capacity to the transmission is a recipe for troubles and possibly being stranded along side the road (not to mention a pretty stout bill for rebuilding the trans) which is never fun. You already have signs of trans wear, so i'd be really conscientious of the strain you are placing on the trans. A shift improver is a solid upgrade when adding a tuner to a truck w/an auto trans, but isn't necessarily a silver bullet. The trans is most vulnerable while shifting and anytime your rpm's are really low and you put a big load on it . . .that much torque can actually cause the trans to slip. If you are easy while its shifting and you don't let the truck bog down and load up, you should be in really good shape on the stock trans for a while. Just remember, the trans (just like a clutch) is a wearable part and only has a given life . . .the more HP you make, the shorter you make the life of the stock trans.

 

There are actually 3 output models for the '03...the California model is a detuned ISB 250 with a power rating of 235hp.

 

I learn something new every day! Thanks for the info.