...and we fear the worst. 157K miles, the check engine light is on again, we smell something weird, we hear a whining sound when we are coasting and clunking occasionally the transmission is shifting. Any ideas anyone? Thanks.

 

Have someone check the drive line connection to the rear of the transmission. My 1999 XC v70 has a similar problem at 175k and the bolts to that u-joint( which is actually a cv-joint) were all loose. I put blue lock-tite on the threads and tightened the allen bolts down... problem solved. Good Luck!!!