transmission problems typical?

I'm currently looking for a used 1500 and am finding that a lot of them (98-02) have had the transmissions replaced at low mileage (40-70k). I'm wondering if this is typical of the 1500's or if it's something to avoid?

i have serviced mine every 60,000 k, and it is still going strong 190,000 in 2000 chev 4x4

my 01 is still runnin strong.. 80,000 on it.

120,000 miles on original transmission, started to do the 1-2 bang so I put in the Transgo ShiftKit 'bout a month ago and now it's driving like new again.

Bert

http://tinypic.com/jkhhlf

I have a '00 with 93,000 and it hasn't fallen out yet!