68 rfe p0740 07 6.7

[Lunadog57]

3500 4x4 with 68rfe bought and told it has new torque converter, turbine, clutches, and valve body, and aftermarket e fan trans cooler. P0740 and p0700 came on on drive home trans temp over heat light came on 3 times. Guy i bought it from aint helping. So how do i go about diagnosing. Im seeing its either torque converter or valve in the pump. Looking to do work myself. Did instsll temp gauge when i first installed drove around town and after an hour went home and when i stopped at idle went up to 220. I havent seen it get tbag high again only up to 180 not towing.