1999 D 5.2 L 318

my check engine light came on...it read 3-4 shift malfunction im thinking the solenoids would that affect the actual gears/internal parts..etc.....

also said somthing about TCC torque converter circuit shift malfuction or soomthing? any info etc....any at all..

im selling this vehicle and have to have it tip top...ive already rebuilt the whole front end added shocks,tires etc...tune up all that good stuff now this...[:@]

any help any at all would be much appriciated