Dodge teamed up with Cummins to deliver the best all-around package in passenger truck history. The Cummins 6-cylinder has remained essentially unchanged, despite a gradual evolution. Pump/injection styles and a switch to 4-valves per cylinder are the only significant changes. We’ll break this down by generation:
1st Generation Dodge Diesel Trucks – 1989 – 1993
First gen Dodges are tough old trucks, powered by the venerable 12v, 5.9l engine. These early trucks used a mechanical, rotary-style pump, known as the VE Pump. This setup is hard to get huge power number out of, but some simple–and cheap– modifications can make them great drivers. Here are some of the things to watch for:
- Steering shafts. These are terribly designed and fail on a regular basis. Good news is that Borgeson has an updated unit that you can get from Summit. A Must-Have upgrade
- Auto Transmissions. These are crap. This is on consistent issue with all Dodges. They work OK behind stock power for a while, but expect to rebuild every 100k or so if they are used heavily or turned up
- Steering box mounting. The frames on the early trucks are not boxed up front and have a LOT of flex in them. This flex can fatigue the metal where the box mounts and cause it to crack. Be sure to inspect this well if buying a used 1st Gen.
- Injection Pumps. For the most part, these pumps hold up well. They can develop leaks which require pump removal. When this happens it may be advisable to simple replace the pump, as rebuilds can get more expensive than an exchange.
2nd Generation Dodge Diesel Trucks – 1994 – 2002
The Second Gen Dodges are still among the most popular. This body style was powered by two different iterations of the Cummins powerplant, the 12-valve from 1994-1998 and the 24-valve from 1998.5-2002. The 12-valve versions are the most sought-after as they P-Pump system allows for easy and nearly unlimited power modifications. The 24-valve saw the introduction of more extensive electronic control systems and some subsequent problems.
- Front Ends. In general, the front end in an second gen will need something every 60k or so. Balljoints are especially problematic. There are better, aftermarket units available that should be permanent fixes.
- Auto Transmissions. Same as above. Although the 47 RH/RE transmissions are better, and feature both overdrive and lockup, they still crumble behind the torque of the Cummins. They can be rebuilt with much stronger components and they will handle 6-700 HP on a daily basis for many miles.
- 12-Valve Engines. VERY few issues with these in general. Biggest issue is failing fuel shutoff solenoids. They can cause a no-start condition. Leaking feed/return lines can also cause no start issues. Cranking up the power will require the installation of headstuds.
- 12v Engines also suffer from the KILLER DOWEL PIN. Not all trucks have a problem, but when they fall out, they tend to grenade the timing gear case. Repair includes removing the camshaft, so it gets expensive quickly. Do yourself a favor and immediately do the KDP fix on any 12v you add to your stable.
- 24-Valve Engines. Fuel pressure is the problem…crappy electronic lift pumps fail without warning and starve the expensive, fragile VP44 injection pump. Look for code p0216 and others for confirmation. Dead pedal on the freeway and no-start hot conditions are also signs that the injector pump is a goner. When you replace the injection pump, ALWAYS replace the lift pump, and you should do so with a better, geroter pump from Airdog or FASS. Other issues include flaky TPS sensors that can cause problems with overdrive.
- Cross-Tube o-rings are also an issue with the 24v trucks. These tend to dry out over time and can swell if you Bio. Either can cause a no-start condition when the truck is parked, especially nose-up.
3rd Generation Dodge Diesel Trucks – 2003 – 2009
The Third Generation Dodge facelift modernized the interior and exterior of the truck line, and saw the introduction of usable rear seats and even the MegaCab. The 24-valve engine lost the problematic VP44 pump and replaced it with the quieter, more reliable Common Rail injection system. But, like with any change, some new problems did arise.
- Injectors. Although the system itself is pretty reliable, the electronic injectors fail around 100k miles.
- Injection Pressure Regulators (The FCA). These things can fail and cause erratic idling issues and other woes.
- Valve Seats. 03-04 trucks don’t have issues, but the 05+ trucks seem to have problems dropping valve seats at high RPM in high EGT conditions.
- Intercoolers. In 2005 only, Dodge used a plastic-tank intercooler. They fail. That is all.
- #4 and or #5 injector lines. The vibration isolators come loose and the resulting vibration causes the fuel line to crack. Cummins has an updated line/hold down.
- Wheel hub assemblies tend to fail around 100k, especially with bigger tires
- Steering linkage. Basically the factory stuff is pretty weak. By 70k expect play in the tie rod ends. The good news is that the 2008+ steering is a direct replacement, the kit from Dodge is pretty reasonable and it is WAY beefier.
- 6.7-powered trucks have the 68RFE transmission. Unfortunately the double overdrive drops the rpm so low that the trucks tend to lug, especially with larger tires. The OD section of the trans has really small clutch packs and they don’t like extra power. Suncoast has beefy upgrade kits that are now pretty well dialed in. They do cost a bunch more than a comparable 47/48 to rebuild.
4th Generation Dodge Diesel Trucks – 2010 -
The fourth generation Dodge Trucks have a complete make over of the body and interior style. Engine is the continuation and refinement of the 6.7 liter 6 inline cylinder Cummins, and 2011 Auto models introduced the High Output version with 350hp and 800 ft lbs of torque. All of the same issues as the Third Gen trucks, with the exception of better steering.