Ford: Fords are very common, parts are inexpensive, and there is a
lot of Ford parts that are very useful in Jeep vehicles. Many Jeeps
use Ford transmissions, so Ford trucks are a good source of heavy duty
transmissions for Jeeps.
GM: GM cars and trucks are even more common and
Ford parts. Since most Jeeps do not use GM parts though, it is a bit
harder to find uses for GM parts.
International Harvester: Most Jeep and IH trucks use Borg-Warner
transmissions. The T-18, T-98, T-15, and T-90 were all used in both
Jeep trucks and IH trucks. Some parts of these IH transmissions
interchange or the transmissions can be converted relatively easily
for use in Jeeps.
Dodge: Dodge trucks are fairly expensive and harder to find than
parts from other manufactures. Their use is limited in Jeeps.