I was checking out a sponsor's web site for some info when I ran across this.
Bad news is it only fits 03-06 trucks and cost is 149.95

Check it out, click click

 

most aftermarket gauge clusters have the trans temp gauge

 

For twice that, you can get a brand new escalade cluster. Look on eBay for Cluster gauges you can get them pretty cheap.

 

I can get the kits for under $100 for the 03-04, the only problem is that you may need to send it out to have a file programmed into the cluster. It is a hit or miss kind of thing. I needed to send mine out to have the file installed.

 

I installed that kit in mine couple years ago. Works great. Not that hard to do.

 

Can you post the installation instructions for that please? Or post how you did that?

Thanks!