10lemonsk

Thanks for the help, guys. I found some additional information that may be helpful if someone else is curious. QCC (who distributes the aftermarket Sauer Danfoss CP series hydraulic pumps) says that with the standard seals "the system temperature should not exceed 180° F (82°C) except for short periods to 200° F (93° C)", see attached and CP180_0601512.pdf (qccorp.com). I'm going to look into ways to monitor temperature and pressure for this system to make sure I'm not exceeding these limits. Also, Chad, I'm concerned about the transmission temps too. I came across the below post that may be of interest to you. This guy installed an external cooler for his transmission that seems to have helped keep temps down and wasn't terribly expensive. I'm planning on looking into this further soon.

I have a 2003 Monaco Signature with the 525 ISX and an Allison 4000. A few months after purchasing this motorhome, I experienced a severe PTO failure that left me stranded, so I've recently replaced both the transmission-driven PTO and the hydraulic pump on the motorhome. I have also drained and replaced the hydraulic fluid with Dexron III (per owner's manual), completed a full servicing on the transmission, and installed a source engineering wax valve kit among other things. My engine now stays below 205 degrees, and my transmission usually stays in a 200 - 230-degree range. However, after completing the aforementioned servicing and taking the motorhome on a 1-hour test drive in the 100-degree Texas heat, I shot my hydraulic pump & fittings with a laser temp gun and they read around 190 degrees. A quick google search for hydraulic systems in general would lead me to believe this is running wayyy too hot, but can anyone else here with a similar set up shed some light on the normal operating temperatures of their hydraulic systems? I'm very concerned about a repeat of the PTO and pump failure, so I appreciate any help. Thanks.