Firmer shifts and reduced slippage can
greatly extend the life of a Ford E40D or 4R100 automatic transmission.
By
C.J. Baker
For
the last several decades light trucks, vans, and motorhomes
have gained incredible popularity. Now we can add SUVs
to that list. Many families use a light truck or an
SUV as their daily transportation. Pickups and SUVs
have become socially acceptable. As a result, trucks
and SUVs have become less utilitarian and more “car-like”.
This transition has included softer suspension, interiors
that are more luxurious, numerous creature comforts,
and automatic transmissions that have soft, unobtrusive
shifts. In an effort to please their customers, Ford
designed their light truck tranmissions and control
systems to provide smooth, car-like shifts. It is the
quality of these automatic transmission shifts, particularly
in the E40D that Ford has used in light trucks, vans,
and motorhome chassis since ‘89, and later, beginning
in ’99, the 4R100, that concerns us in this article.
While some people find the softer shifting to be pleasing,
others have complained that the shifts are mushy, lazy,
loose or slippery. The car-like shifts from these truck
transmissions are accomplished by reducing the hydraulic
line pressure in the transmission, which in turn slows
the speed of the shifts and allows some slippage to
soften the transition from one gear to the next. While
this tactic results in velvet-smooth shifts, it does
nothing good for the automatic transmission, and in
fact, Ford has had substantial warranty exposure from
both of these transmissions. Slippage during the shifts
is hard on the clutch packs and it increases the transmission
fluid temperature – the biggest enemy of an automatic
transmission. The harder the vehicle is driven, the
more the transmission slips on shifts. The problem
is further aggravated if the vehicle is called upon
to haul or tow a heavy load, such as an RV. Heavy motorhome
chassis using the Ford automatic have the same problem.
The
basic design of the transmission is not at fault, but
rather the way the shifts are controlled. Mechanically,
the transmission is sound, strong, and durable. If
the vehicle is driven with moderation and light loads,
the transmission life expectancy is good. However,
if the vehicle is driven aggressively, or with heavy
loads, used for trailer or RV towing, or operated with
increased power, such as from a Banks power system,
transmission problems can begin.
At
Banks, we are acutely aware of this situation with
the Ford E4OD and R4100 transmissions. You see, the
substantial gains in torque and power from Banks power
systems also tends to promote transmission slippage
and increase transmission fluid temperatures unless
the transmission shifts are suitably upgraded. Since
reliability of the entire drivetrain is a primary concern
when we design any Banks product, it was apparent that
we needed to address the E4OD and 4R100 transmissions
as well.
Both
the E4OD and the 4R100 are electronically controlled
four-speed automatic transmissions. They use two shift
solenoids and a third solenoid to control torque converter
lockup. They also use an EPV (electronic pressure valve)
to control hydraulic line pressure. The solenoids and
EPV are controlled by the Ford on-board EEC (electronic
engine control) processor. Gear selection is made by
the combination of the two shift solenoids that are
or are not actuated. The EEC monitors throttle position
and vehicle speed to determine the load on the transmission
and varies line pressure accordingly for the shifts.
Light throttle and a rapid change in vehicle speed
(acceleration) mean a light load, heavy throttle and
rapid acceleration indicate a moderate load, as does
a light throttle and slow acceleration. Full throttle
and slow acceleration mean a heavy load. The heavier
the load, the more transmission line pressure is directed
by the EEC to firm up the shifts, albeit still in compliance
with the car-like shift design. Unfortunately, the
EEC does not recognize additional power output when
the engine is upgraded with a Banks system. Consequently,
the EEC may recognize a light throttle opening and
fast acceleration as a light load when the additional
power output at light throttle with a Banks system
is actually generating a moderate to heavy load on
the transmission. Such situations increase clutch slippage
and damage will begin to occur.
The
solution to the problem is the Banks TransCommand,
an automatic transmission management computer that
overlays the stock EEC control of hydraulic line pressure.
The TransCommand also monitors the throttle position
and vehicle speed to sense vehicle load, progressively
increasing line pressure above that signaled by the
EEC up to the maximum Ford specification of 190 PSI.
Pressure is never increased beyond the Ford spec or
beyond the capacity of the transmission pump. This
protects the pump and the transmission seals.
Essentially,
the TransCommand accelerates the rate at which line
pressure is increased. For example, at idle, in neutral
or in gear, the TransCommand has no affect on the line
pressure. However, when the EEC commands increased
pressure, the TransCommand automatically increases
that pressure by a calibrated percentage. The more
the EEC increases the pressure, the more the TransCommand
will add pressure until maximum pressure is attained.
At increased pressure, clutch pack “slip time” is
decreased. Light throttle shifts remain smooth and
firm, while full-throttle or heavily loaded shifts
are solid and decisive. The line pressure is always
proportional to the load to avoid any harsh or jarring
shifts. Interestingly, when the “slip time” is
decreased, the vehicle also accelerates faster, which
is a side benefit of the TransCommand.
The
Banks TransCommand was originally developed for turbo-diesel
applications. Without the TransCommand on a turbocharged
vehicle, the transmission would be likely to experience
premature wear and excessive fluid temperatures. The
TransCommand worked so well in turbocharged diesel
applications that it became apparent that it would
be equally effective in gasoline engine applications.
In fact, virtually any vehicle equipped with an E4OD
or 4R100 transmission will benefit from reduced slippage
and lower transmission fluid temperature with the installation
of a TransCommand. This extends transmission life.
It isn’t necessary to add a power system to the
vehicle to use the TransCommand. Numerous fleet owners
have added the TransCommand to their Ford vehicles
to reduce maintenance time and expense.
The
TransCommand is easy to install. Installation can typically
be done in ten to fifteen minutes. For diagnostic purposes,
there is a “bypass” plug supplied with each
TransCommand that can be used to return the system
to the original stock Ford configuration in minutes,
should there ever be a problem. The TransCommand carries
a two-year limited warranty, and it is designed to
last the life of the vehicle while enduring temperature
extremes, dust, moisture and vibration.
Do
you really need a TransCommand if you have a Ford E4OD
or 4R100 automatic?
Not
all failures of these transmissions are related to
clutch wear, but the majority are. Therefore, any vehicle
with one of these transmissions will benefit from the
installation of a TransCommand by reducing slip time
during the shifts. If the vehicle is used to carry
moderate to heavy loads, such as towing applications,
van to motorhome conversions, Class-A motorhomes, tow
trucks, or even ambulances, the TransCommand should
be considered mandatory. Moreover, if power output
is increased by any means, the TransCommand is a must.
In fact, the TransCommand is included with the PowerPack®,
Stinger-Plus, and Stinger power systems for all 7.3L
PowerStroke turbo-diesels, and with the Sidewinder
package for the ’89-93 6.9L and 7.3L diesels fitted
with the E4OD transmission. For all other Ford applications,
including 6.8L (V-10) and 7.5L (460) motorhomes, the
TransCommand is highly recommended.
If
you’re still not convinced that a TransCommand
is a great investment, consider the cost and inconvenience
of replacing that automatic transmission. You’ll
be glad you did.
|
