I’m working on a radiator and transmission cooling upgrade for my E53 x5 and had to go to ZF to get a few numbers to help with my planning. Could have been poor google use on my part, or they may have actually been not well publicized. I thought I’d post them here for the handful of guys with this transmission. Specifically, I’m upgrading my radiator to a CSF Race E39 M5 dual pass unit, which will entail modding my tranny cooler to an air cooler since the M5 radiator doesn’t have the fitting for the tranny cooler hose (manual gearbox). I was trying to find the pressures and temps to make sure I came up with the right hose, fitting and thermostat solution.

zF reports that the 5HP24 operating temp is from 170 to 190 deg, and the fluid pressure is about 29 psi through the cooler, and as high as 290 psi at the pump at high rpm.