2000ford f150 lariat 4x4 5.4 4R70W. Transmission trans is slipping I been told I need to rebuild or new one. But others said I couldn’t do it myself because it would lose its memory or may need to be reflashed. Then other said the truck was old and was no problem doing it myself . Now confused my truck is sitting in the driveway .
Ok, replace the trans yourself and IF it needs to be reflashed, have it towed to the Ford dealer for just that. But I don’t think you will need a reflash.
Yes it will.
A major automatic transmission rebuild isn’t a diy’er job. At least not for 95%+ of diy’ers. Replacing the trans, yeah, a lot of diy’ers could do that. But even that is still a very big & complex & heavy-lifting job. Good idea before going down the diy’er path, ask a Ford dealership how much the re-flash is going to cost. I doubt the fee for that is going to be a show-stopper. But you need to know that info up front to make your decision.
How many miles on the transmission and how long has it been slipping? These transmissions are somewhat finicky about fluid life and there’s at least a possibility that a fluid and filter change could fix it IF the slipping hasn’t been too bad and it hasn’t been going on for very long.
The 4R70W is a good solid transmission and with regular fluid changes should outlast the vehicle that it’s in. So has the transmission been serviced (30 to 35k miles) regularly? My gut feeling is not.
We used to have lots of Ford F-150s of this vintage . . . with the same transmission . . . in our fleet, and they weren’t particularly finicky. When serviced as per the severe service schedule, they held up just fine
As for software flashes . . . take care of any mechanical problems first, whether that involves an overhaul or repair, then deal with re-learning the gear shifts. It might be called “re-adaptation” . . . . every manufacturer has their own terminology . . . and this involves the use of a professional level scanner. Flashing means installing updated software, but that’s not going to fix a mechanical problem on a nearly 20-year old truck. The original software should be just fine, provided the mechanicals are taken care of and all the gear shifts are re-learned, as stated above
It probably doesn’t make economic sense to fix the transmission on this particular vehicle
But the truck might be in otherwise fantastic shape . . . or there may be an emotional attachment of some sort