help me ID this 8.8 rear end

Can you tell me what vehicle this 8.8 rear end came from? This 8.8 is in my Mustang, but I'm having so many problems with it, it's unbelievable. Simple brake change? Not with this thing... I just want to check and make sure the collision center put the correct 8.8 in my '99 Mustang GT.

Here's what the tag on the differential cover reads:

S229H
3L27 88 1M17

I sure hope that 88 in the center isn't from an '88 mustang... Any suggestions what vehicle and year this thing is from? Thanks for any help!

Thanks for the replies, I appreciate it. Well, after having done the drivers side (which was a pain)... I had a problem getting the Caliper back on and aligned with the top bolt hole. I had to use a hammer and jam the bolt in a little bit. After doing the Passengers side, and noticing that both top and bottom bolts for the caliper mounting, were easily moved inward and outward for mounting the caliper. So, I'm guessing that the drivers side top bolt is messed up, and I'm not able to pull the mounting bolt/slider out (as so I've tried to)... Does that mean I would need a new caliper bracket?

With the passengers side, I couldn't get my tire off. I had to kick one side of the tire really hard & carefully so the car wouldn't tip over. The rim is kinda carved out now, where the rim connects to the axle (or is it the hub?) Well, that piece is rusted, but I don't really see how it could carve the rim like it had. It makes me furious to know that they forced it on there to begin with. I just cannot find a collision center who does honest work.. but then again, if you want something done right you've got to do it yourself. Lesson learned.

God bless, and good day!

Thanks, I'm guessing I'll need to replace it. I'll try and take it out and see what i've got. Any idea on how much that will cost?