The Ford E4OD and 4R100 four-speed automatic transmissions were essentially the same transmission with different names. However, Ford slightly beefed up the 4R100’s internal components to solve some lingering performance issues with the E4OD. Ford also matched the 4R100 with larger diesel-powered engines. The E4OD replaced the venerable Ford C-6 automatic transmissions. Both the E4OD and 4R100 were electronically controlled, replacing the C6’s hydraulic-controlled transmission technology.
The E4OD four-speed automatic transmission debuted in the rear-wheel drive 1989 Ford F-Series pickup trucks, and E-Series full-size cargo and nine-passenger vans. A year later, Ford offered the E4OD in the Ford Broncos. They were available on the Broncos until 1996. The Ford Expedition received the transmission for the 1997 and 1998 model years. The E4OD marked a major shift by Ford from the hydraulic controlled technology to computer controls to shift gears. However, it did have some reliability issues. It had weak seals that allowed moisture inside the case, and occasionally the gears inexplicably shifted into neutral while the vehicle was in motion. The overdrive light also tended to light up while accompanying hard shifting or slipping. In 1998, the 4R100 replaced the E4OD.
The 4R100 reflected Ford’s new identification system for its transmission lineup, but it also solved some problems associated with the older E4OD. While the E4OD’s problems were not major or widespread, the Ford eyed the new 4R100 with the plan to solve these bugs. The 4R100 also matched Ford’s big 7.3-liter Power Stroke diesel engines from 1999 through 2003. Yet even the 4R100 had its own problems. It often failed to keep up with the increased torque output of the bigger engines. Aftermarket 4R100 versions solved the problem by increasing its torque capacity to 1,000 foot-pounds. Among the aftermarket improvements were a high-performance shift-kit and power valve, and heavy-duty clutch. When the 6-liter Power Stroke engine replaced the 7.3-liter version for 2004, the 4R100 disappeared with it.
Ford reserved the 4R100 for its performance trucks and heavy-duty sport utility vehicles. It matched engines in the 1999 to 2004 Ford SVT Lightning performance truck, the 2002 to 2003 Ford F-150 Harley-Davidson Special Edition, the 1999 to 2003 Ford F-250 and larger Super Duty trucks, the 1999 to 2003 Ford Expedition SUV equipped with the 5.4-liter V-8, the 2000 to 2003 Ford Excursion and the 1999 to 2004 Ford E-Series vans. The E4OD and 4R100 were huge transmissions at 27.25 inches long and not easily applicable to non-Ford trucks and vans. Shoehorning the transmission into another vehicle requires extensive modifications.
The gear ratios for the E4OD and 4R100 transmissions were identical: 2.71-to-1 for first gear, 1.54-to-1 for second, direct 1.00-to-1 for third and 0.71-to-1 for fourth.