The D100 probably has the 3 speed standard transmission. If so, it doesn't use gear oil in the transmission. It uses Dextron II or III. The fill plug is found on the side of the transmission about half way up.
Dextron 2
Should be an A727 tranny. I have an 1989 Dodge D100 3.9 v6 and the transmission in it is an 904 a lighter version of the 727.
Facing the front of the truck, it is located on the intake manifold on the right side of the carb.
On a 1988 Dodge D100, the fuel pump relay is typically located in the power distribution center (fuse box) under the hood. It can be found near the front of the engine compartment, usually mounted on the driver's side. Consult the owner's manual or a repair manual for specific diagrams and detailed locations, as it may vary slightly depending on the vehicle's configuration.
The firing order for a 1988 318 is: Right side: 1-3-5-7. Left side: 2-4-6-8. This is as viewed from the front of the truck.
The 1987 Dodge D100 truck typically comes with a fuel tank size of approximately 20 gallons. However, the exact size can vary slightly depending on the specific model and configuration. It's always a good idea to check the owner's manual or consult with a dealership for precise specifications.
== ==
Timing on this truck is at top dead center for both manual and automatic transmissions. If it is an original California truck with all the smog devises time it at 4 degrees before top dead center.
torque flight 727
There is none.
its under the steering column
7700