I bought the vehicle new, and it never did this until just recently (at about 70,500 miles). There was no evidence of metal in the original transmission fluid, but it was somewhat dirty, so I had it changed out to see if that would help. The new fluid has been in for several weeks now (about 500 miles). It appears clean and clear red, but didn’t help with the slippage. Again, no visual evidence of any metal contamination. The vehicle has been well maintained, with all scheduled servicing. It has never been used to tow anything, and until now, has given good service as a typical suburban family sedan. Thanks.