Tranmission Question !!

[Already Gone]

I think I have found my keeper Burb. Its a 1990 Silverado C10 with the 5.7 litre, originally from Texas so it has the Rear A/C.. It also has Buckets, 3rd bench seat, barn doors, two tone Black with red center and red interior (haven't seen another with this color combo around here) and rallye wheels, although I'd prefer the buds. There is no rust and it has been maintained religiously by the older pastor I'm buying it from. He said he has done the rear end and put a new A/C compressor on last summer. My question is that the Burb has 198,000 miles on it and the trans has never been done,although it gets serviced every 2 years. It has pulled a smaller utility trailer a few times and the previous owner bought it 10 years ago with 75,000 miles on it, so I'm certain the trans hasn't been abused. Has anyone has experience with this trans getting lots of miles without a rebuild? I'm just trying to figure out how much to pay for it cause if I need to do the trans within the next 10 or 15,000 miles I have to factor that into the deal.