I have an 02 SD w/ an auto. Couple days ago going around a turn it shifted to 2nd. It was a mean hard shift not loose just hard. The next day it was wanting to go but not keeping up w/ the rpms in the same gear. Seems to be a low rpm problem, if I let off then gas it it takes right off. Then yesterday, it started flashing the OD light on the shifter arm. Any ideas? Also, I changed the fluid and filter about 5000 mi ago at 130,000 and added an SCT programmer, but have not been abusing the truck. All of these problems occured w/ in 50 miles. Thanks in advance.