Threw the code in July on my 2000 3.9L V6 Mag with 90,000 miles, most places told me I needed a transmission rebuild for around $1800-2200. Decided to take to dealer to have TCC and OD sensors checked first. Replaced A31 (TCC) sensor, was good for 1-1/2 weeks, then check engine light again with P1740 code. Back to dealer for more investagation. Found bad ground in PCM, dealer wanted $1300 for NEW unit. Checked around and ordered one from E-Bay ($164) with lifetime warranty. Waited 10 days for unit to arrive, plugged it in and have not had the code reapear for the last 350 miles of city and highway driving. Note: researching PCM units, found autoparts and web dealers need, year, make, mileage and serial number of old unit to program chip otherwise junkyard replacement will throw another code and dealer will have to reprogram the replacement. So far so good, truck is running good .