If my trans really needs a rebuild, I am going to try and tackle it myself. I've got the space and the tools as well as being pretty mechanically inclined. My question is whether or not the torque converter is actually the issue. Could it be a valve body issue with a worn valve letting pressure through to the torque converter causing it to unlock and slip at high rpm? Could I use a 4.6 torque converter in my 4.4 if the torque converter is the root of the problem?

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2001 4.4i E53 172k 01/01 Mfg

Mods: Led interior lights, rear footwell lights, black powder coated rims, carbon fiber wrapped interior trim, matte black ecs kidney grilles, arnott air springs(rear), rear console-quad usb chargers, K&N air filter, akebono ceramic brake pads & zimmerman rotors, black painted calipers, 5% rear window tint over factory tint, 50% front window tint, rear airbags activated, 4:3 nav head unit auxilary input, diy trans rebuild at 160k, spyder led tailights, hella horns