I recently rebuilt the 4r70w transmission in my 03 f150 supercrew. Realized later that I probably put the wrong fluid in (I just used generic atf, said it was good for dexron and mercon transmissions). I guess it's supposed to have mercon v. Is there anything I can do, short of having the tranny flushed, to make sure I don't ruin the brand new parts? It seems to drive fine, other than being late on the 1-2 shift. (That might be the accumulator spring).
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a 2003 probably does not have a drain plug in the converter, so you will leave 8 quarts of oil in the converter if you pull the trans pan and take that 5 quarts out........... one option is to remove the trans outlet tube that goes to the radiator and point it into a bucket.. start the truck and pump out 3 quarts... stop and refill 3 quarts.... start truck and pump out 3 quarts... stop and refill 3 quarts.... repeat a few times... This is not ideal, but you should get a good portion of the MERCON V into the system... If the ORIGINAL oil you put in is actually a MERCON equivalent, then your not in too bad of shape.. Earlier transmissions used the MERCON and was later upgraded to the MERCON V.