A Google search led me to the thread on this forum, but the links provided show that the files have been removed. The Mod was "Realistic Engine Sound Fx v0.9." This added a start up sequence to the diesel upon surfacing, based on a real Fairbanks Morse engine. I believe forum member Wilhelm Tell was the mod's author. The thread here on Subsim dates way back to 2007, and I had the mod at one time, but apparently didn't save it

. If anyone has this sound file, I'd appreciate it. Thanks.