well i have a 2.9 not a 3.0 but theres no place here for a 2.9 so heres my problem

got an 88 ranger xlt extened cab 2.9 m5 4x4 motor runs good if i pull start the truck so i figured id check the selonoid first 11.48 volts on both sides with key on so i pulled the starter checked it with a jumper box and nothing so i picked up a remand starter popped it in... nothing so i tryed it on the jumper box and the starter would turn very slow so i had a 4.9 spare starter for my other truck tryed it on the jumper box and worked fine so i know it wasnt the box so i took the wolt meter under the truck with me n i was gettin 11.24 volts at the end of the cable so i replaced the cable from the battery to the selonoid then the selonoid to the starter then i replaced the ground from the battery to the motor then replaced the smaller ground wire from the battery to the core suport then i made a cable to go from the starter bolt to the frame and cleaned a section of frame b4 putting the wire on then i took that starter back the put it on there tester and it worked so i told them i still wanted a diffrent start so i got it put it on n nothing so i took it off hooked it to the jumper box and same thing. so i pulled the cable from the seloind to the srater back to the top of the engin n i hooked up my 4.9 starter and grounded it on the intake the selonoid clicked and i could hear a struggle but wouldnt kick over

also the battery and all relays are new

im stumped