my fan looks to have significantly more than just three ball bearings, mine looks more like 10-15. If I spin the fan with the engine off, it spins one direction with resistance (fluid) and the other direction spins really smoothly. If I 'flick' it in that direction it will spin for at least 3 full revolutions with absolutely no noise.
I have a Superchips Traildash so I can see in real time what the engine and tranny are doing. In my 15 minute drive to work the jeep is approaching 220 degrees coolant temp and 170 on the trans. Yesterday early afternoon cruising down the freeway for about a 20-25 minute drive at 60 mph (103 degrees outside temp), the engine moved between 217-222 degrees and the trans hovered around 195. In years past this would have sent the fan into full speed mode but not now. FWIW, the fan currently has a new Ford solenoid with the Ford pigtail. If I shut the jeep down, then restart it, the fan will try to get to full speed (not nearly as fast as it use to) and the hydraulic motor has a crunchy sound to it. If you crack the throttle open, the fan shuts off (or slows way down). Power steering is not affected at all by this and is working great. This leads me to the fan motor itself, or maybe that integrated diverted valve in the fan motor that regulates the pressure going to the steering box vs. fan, but not the fans 'speed solenoid'.
As test, I unplugged the temp sender. After a few seconds on startup, the fan speeds up. It does not sound at all smooth anymore nor is it spinning as fast as it use to, but again, as soon as I crack the throttle to increase the engine speed, you hear an audible noise (pressure sounding) and the fan slows way down and the power steering pump 'relaxes'. After the jeep comes back down to idle, the fan resumes full speed. In my mind, if the pump was going out (it was replaced with a brand new Mopar Unit at 65K) the steering would be affected during all this, but it isn't. Any reason someone would suspect the PCM?
So my wife and I talked a lot. Aaron (narnmv) and Jeeples, thanks for setting my mind at ease a little more with the confirmation on the Valvoline fluid as well as future availability of decent used units. We added up what it would cost to get the AC line re-routed, the correct shroud with '04 4.0 fan motor (2-speed), fan clutch, fan blade, regular power steering line from pump to box bypassing the hydro setup, electric fan adjustable regulator, fluid and all, and we get within a couple hundred bucks of just using the brand new hydro unit I have in the garage. As well, I will have a second brand new spare 3-wire solenoid to hang onto as a back up. I can see that Napa has both the pump to hydro pressure line and hydro to box pressure lines so long term I can still get the lines. I plan on owning this for a really long time. Case in point, my '78 Cherokee Chief, parents purchased new, she has a tick over 326K miles and counting. This WJ should be the same assuming it doesn't get hit.
Aaron, you indicated you were wanting to convert...how will you be able to control the solenoid, will you need to get a different PCM? Do you want to convert due to cooling issues or fuel mileage issues or other?
Parts question, where can we find the rubber o-rings for the larger 1/2-inch pressure line going from the pump to the hydro unit? Is it a standard size that can be found in an ACE Hardware or something? Mine are hard and de-formed so a little tough to gauge against new ones. Anyone have a size (o.d. vs. i.d. and thickness) they found that works?
Gonna season on this a bit more but I am leaning towards sucking it up and installing the new hydro unit I have, new primary pressure line, flush the system and cross fingers. Any reason someone would suspect the PCM at this point? Thanks for all the replies and info. Much appreciated.
'78 Cherokee Chief: 360/TH400/NOS QT, '04 Grand Cherokee: 4.7/545RFE/242HD w/SYE, JK Rubi front axle, 4.56 gears, Protofab rear bumper/tire carrier