- Author: Mike Riley, Technical Editor
- Unit: E4OD/4R100
- Vehicle Application: Ford trucks
- Issue: Component changes
A fair number of components in the E4OD have changed since it first launched in 1989, affecting virtually every area of the transmission. One key area that was altered was the pump assembly. A noticeable change occurred in 1995, when the output volume was increased. The big facelift, however, happened in 1998 with the release of the 4R100, which replaced the E4OD.
In an effort to standardize components, Ford switched to a common pump body and cover casting to accommodate three pump-assembly types: E4OD, 4R100 with on-off lockup and 4R100 with PWM lockup. The new castings were marked F81P to denote 1998. As an assembly, the new E4OD pump will retro to 1989. The OE part number is still F81Z-7A103BA.
The two 4R100 pumps were produced to accommodate model variations such as PWM/non-PWM and with-PTO/without-PTO applications.
Initially, pumps that were made to be used on vehicles with a PTO had a bearing in the stator-support bore for the input shaft. Almost immediately, however, the bearing was changed back to a traditional bushing as in E4OD. With that change, in effect there was just one concern: Did the model require an on-off lockup-clutch apply or a PWM apply? All diesel applications and certain gas applications used PWM, whereas few gas models had an on-off lockup. The original PWM part number was F81Z-7A103CA but was later changed to 8C3Z-7A103C.
The on-off pump part number, XC3Z-7A103EA, has now been discontinued by Ford due to limited application and usage. If needed, an E4OD pump can be used instead, by changing the stator support.
Pump identification is not too difficult. First, verify the F81P casting number on the pump body and cover. To distinguish E4OD from 4R100, just compare the stator supports. The E4OD stator support coast-clutch-drum sealing rings are positioned toward the pump cover (Figure 1). That puts the drum bushing journal away from the cover.
All 4R100 models are opposite E4OD due to the added feature of a PTO. The bushing (or bearing) journal needed to be forward to handle the extra load of a PTO gear on the coast-clutch drum (Figure 2). The journal diameter is the same whether the coast-clutch drum is equipped with a bushing or bearing, unlike in other transmissions that have had similar model variations.
The other identification concern is 4R100 with or without the PWM TCC-valve lineup. As indicated in illustrations 1 and 2, look at the TCC valve bore to determine end-plug depth. E4OD and non-PWM 4R100 TCC-valve end-plug depth is more than an inch from the pump-cover O.D. A PWM TCC-valve end plug is recessed only about 1⁄4 inch from the pump-cover O.D., because a PWM TCC-valve end plug is not just a flat plug. A PWM design is actually a long sleeve that contains a valve. Always ensure that the correct solenoid block is used, based upon pump design.
The other component that goes hand in hand with the pump upgrade is the coast-clutch drum. Initially, three coast-clutch drums were used to cover E4OD and 4R100 models. As expected, Ford could not leave well enough alone. Some things just needed to be tweaked.
At least the E4OD coast-clutch drum did not change. The E4OD drum is cast iron with the support bushing toward the back of the bore (Figure 3).
Two coast-clutch drums were released for the 4R100 in 1998. Instead of cast iron, the drums were stamped steel (Grob). With that modification, the coast-clutch steels were made with wider teeth. The drum that was produced for non-PTO applications had a support bushing like E4OD, although it was situated toward the front (Figure 4). Non-PTO drums had two friction plates and the part number was YC3Z-7G387AA.
Both E4OD and 4R100 non-PTO drums use a thrust washer between the drum and pump (Figure 5). Unlike in other transmissions, the washer is not selective.
The other 4R100 drum released in 1998 was for PTO models. The PTO drum was basically the same as the non-PTO type, except for a big gear mounted to it. The PTO drum will accommodate three frictions instead of two. In addition, there is a ball bearing that supports the drum instead of a bushing (Figure 6).
One other minor difference is that it does not use a thrust washer between the pump and drum, due to the bearing inner race extending outward to contact the stator support (Figure 7). The PTO drum part number was YC3Z-7G387BA, before more changes occurred.
For some reason, Ford decided to upgrade the non-PTO drum to increase capacity by changing from a bushing to a bearing design, like the PTO type (Figure 8). That also meant no more thrust washer between the pump and drum. The drum still uses a two-friction setup. The non-PTO drum part number changed to 1C3Z-7G387AA.
To further complicate things, a new coast drum was released for PTO applications. The modification is limited to the bearing area. The bearing inner race was changed to provide better bearing lubrication
A narrower inner race enables more fluid to enter the bearing from the pump bore. To trap fluid in the bearing, the inner race is now flush with the outer race and an oil dam (washer) with a slight undercut was added to control flow (Figure 10). The oil dam must be used with this type of PTO drum, but not with the previous PTO drums or the stack-up will be wrong. The new drum part number is 1C3Z-7G387BA. As an assembly, the new design will retro to 1998.
Anything to make life easy, right?