Two Letters Re: Diesel Engine Vehicles

Hi Guys,
Even if those who are skeptical read your blog, they will come back for more. I am very impressed and moreover grateful!

Quick comment on G.O.O.D. Diesel Variants: You have pointed out the great benefits to Diesel power plants,…it is very important to know that you are looking at a SUBSTANTIAL weight increase on the front axle [versus gas engines]. This should be known not only for adjusting the way you execute a maneuver, but the huge disadvantage that you will have in soft, or bottomless soil, (i.e.- sand/mud). If not weighted sufficiently equally on both axles, you will find yourself spinning circles around the front end that has just dropped in. I recommend the widest tires you can fit on the front end to help out anyway possible. Also, diesels operate at a much lower RPM than gasoline engines. When stuck, Low Range or Low Gear will not sufficiently “clean out” the tread lugs. So [briefly] put it in High gear and let the sufficient torque spin the tires and work up a higher speed at the wheel if necessary to get “un-stuck.”

Forever Grateful, – The Wanderer

Mr. Rawles,
I would like to suggest a few links for anyone wanting to know more about Cummins engine equipped trucks. They are:

These links will give everyone a good feel for the differences in these trucks. To summarize them, the Cummins Turbo
Diesel engine placed in Dodge Ram trucks starting in the 1991 model year went through 4 phases to the present day.
Generation I engines were all 12-valve direct mechanical injection engines with a turbo charger. Generation II engines were
introduced when the body style changed in 1994. The Gen. II engines were essentially the same as the Gen I except the
injection pump was changed for higher output. Mid-way through the 1998 model year, Dodge changed to a 24-valve
electronically controlled engine (You can tell the difference by looking at the door-mounted data plates–and the distinctive sound of the engine.) These are the Gen III engines. The fuels system on the Gen III engines is weak due to a faulty transfer pump design causing premature failure of the injection pump. This is very expensive to replace. (I know from personal experience.) The engines changed once again in 2003 when the newest body style came out. These Gen IV engines are much quieter than their predecessors but they are also electronically controlled.

Transmissions in the Gen I and early Gen II trucks were mechanical, and many of the Cummins trucks had manual
transmissions. The Gen II trucks used a NV4500 5-speed manual transmission, and this tranny continued to be used
through the 2003 model year. Beginning in mid-2001 Dodge introduced the NV5600 6-speed manual behind their 24-valve high-output engines. These trannies can be retrofitted to the 12-valve trucks and offers a nice gear split with the extra gear. These manual transmissions feature a PTO access panel on the passenger side of the housing for running equipment if desired. The transfer case was a constant, the NV241HD manually-shifted transfer case. This t-case features a 2.72:1 low range, and coupled with the granny low of the transmission offers some really great [ low] crawl speeds for off-roading. The front axle in 4×4 models was typically the Dana 60 and the rear axle was the Dana 70 (single wheel 2500 models) or the Dana 80 (dual wheel 3500 models.) A limited slip rear axle was offered as an option.

Over the years, power levels steadily rose, and turbo chargers changed slightly, but all-in-all they are extremely reliable, very fuel efficient, and much sought after. Finding a 12-valve Cummins truck in decent condition is next to impossible in my area, and I imagine the same holds true elsewhere. – B.B. in Louisiana