ALL vehicles made in 1996 and later are OBD II, even Yugos. I have never seen a 3 speed anything with 5.2/5.9 in 20 years of taking them apart. I will admit, we avoid vans so not as many taken apart. I have never heard of any Chrysler V8 using a RH after 1995. Not saying its not possible for 3 speed, but I wouldnt believe it unless I saw one. How did you determine they were 3 speeds?