One problem related to transmission not engage has been reported for the 1998 Dodge RAM. The most recently reported issues are listed below.
Transmission overheated ,overdrive automatically disengaged. The odor of burned transmission oil was evident. This was a new transmission and was replaced with a rebuilt transmission by the dealer at $50 deductible. The rebuilt will only be warranted for the first 12 months or 12000 miles. I suspect the transmission is either undercooled or a failure to use the proper atf fluid caused this. Vehicle is under service contract and is serviced for all fluid changes by the dealer.