I had this same problem
First it was 1st and 2nd only ..then 4th and 3rd only. First time around it was the linkage...just came apart...once repaired it lasted about 2 weeks before the shift cable snapped in two...And lucky for me they dont make the 98 Shifter cable any more...so I had to go to a 99 cable...hope you fare better than I did. ($450.00 to get it back on the road)
E0 #4384 of 6535
Born Jan. 9 1998
My SVT from the ashes
147,466 miles, purchased Nov. 2002 @ 76,559 miles