Ok, did I read this right, he just had the coolant system flushed and changed, not the transmission fluid?

If the transmission fluid hasn't been changed, then it would be super easy to get a sample of the current fluid and send it off for testing to be sure.

I waited and waited to do the bypass on my wife's 2005, which I shouldn't have. When it was time for a new car for her, and time for me to sell my older truck and adopt the X, the only way I was keeping it was with an analysis of the transmission fluid. I did the bypass, and in doing so got enough old fluid drained out to send in for a sample. I used Blackstone Labs and highly recommend them, They will also mail you out free sample containers, although you would probably be in a pretty big hurry so you could put the sample in your own clean/new container and send it in UPS NDA. I can PM you my report so you can see a sample of what kind of data you would get from them.

 

if he didn't flush the transmission then any symptoms would be in the transmission still. Check the transmission fluid...5k should be enough miles for everything to mix real well again.

I also think that the factory service manual calls for the transmission drain(or flush) at 100K.

 

I agree that 5000 miles would be enough to see evidence of contamination.

I'm not sure about Grease Monkey chain, but we got our radiator flushed at Jiffy Lube a few years ago and the coolant looked only slightly better - they often use a pump to drain out the old fluid, but only gets "most" of it - there is usually enough dirty old stuff to mix with the new fluid, greatly reducing the effectiveness - sometimes even knocking loose scale or creating blockages. Just my $.02

You can take it to a independent mechanic familiar with xterras for a pre-purchase inspection. It may save you several thousand dollars.