simp5782,
I put the 7155 behind a Detroit Series
60 430/470 hp, 1650 torque a year ago now. I have somewhere around 60,000 miles on it with no problems other than last winter when the temp dropped below 20 degrees, I believe the rear clutch would slip a little near peak torque in top gear. I increased the air pressure to the rear clutch which seemed to help. The transmission is rated at 1350. Think I will heat the oil with coolant to avoid the problem next winter.
I have posted pictures of the install in a album under my profile here on SS. A couple of them have measurements of the drive ring fitted to the standard flywheel (simply removed the clutch) and measurements of the adapter on the tranny. The flywheel and housing will need to be clean and all openings sealed as you will now have oil in the housing with this tranny.
The Western Star has a AD-9 air dryer on it - a very good dryer. I did not install an oiler or a filter system nor a valve body heater and had zero problems with that part of the tranny. However, this truck is operated weekly and does not sit.
Got to get back to work, If I can be of any assistance, just ask and I will try and help you out.