[whiskyb]

They are prone to a mechanical diode failure. You can go to thedieselstop.com and find out all kinds of stuff on them. The trm1620 hd replacement from ford was around 3500 and that is with me doing the labour. Then they will not warranty it unless you put in a new ota cooler. Since heat is a problem with that tranny the recommended upgrade is the cooler from a newer 6 ltr. Up here in Canada the dealer wanted nearly 750 for that. Good thing for the internet as I found one in Rhode island for half that. I have about 350000k on my truck and it is my daily driver. I would not trade it for a new one. DPTUNER makes a great programmable chip for it that really brings it to life.