On my 2008 and 2013 Buses with ISL's that hose goes to the hydraulic pump on the passenger side of the engine. I had a leak at the lower end where the hose connected to the pump that I could not fix with new and tighter clamps, so I replaced the hose. I got my replacement hose at a local hydraulic shop, and new, high end clamps at a local diesel shop. No special part number, just xx feet of hose and trimmed as needed. Since I had to drain the reservoir anyway, I replaced the Dextron fluid with Transynd. Since Dextron is no longer required to meet ANY testing/composition specifications, I thought it was a good idea, and after checking with Tom Johnson, the man who designed Transynd for Allison, (https://www.irv2.com/forums/f125/for...eer-89293.html
) I switched. Of course I also switched to clean filters. 20,000 miles so far and no problems.