Hi 03XLT4X4!
I would do it. I would not push the trans service past about 50K miles. The tranny needs, or at least benefits from preventative maintenance service just like regular oil changes for the engine. I've tried stuff like this and paid the price. I once tried to save money on tune up parts and the distributor rotor [when I was much younger!] wore down so much it just quit running when I was on the freeway!
Your trans will go much longer than the engine without service, like mine has [I'm still guilty], but it does not help to continue to avoid the service. There is wear and the Trans fluid does deteriorate over time.
There are always stories about some guy whose engine or trans ran fine for years and then as soon as he changed the oil, it broke. I believe that these stories are the exception that gets reported and re-told just because they are such anomalies and are the exception that proves the rule and are just a coincidence. What usually really happens is that there was a problem with wear and it was going to fail anyway, it was just coincidence that it happened when the guy finally did the maintenance. Just as likely is that the part of the story that does not get told is that the guy either felt guilty about waiting so long, or actually began to hear a noise or felt a vibration or some such and then he did the service hoping that it would cure the problem. Don’t be that guy!
Do not feel like you are saving money by postponing the maintenance. There is wear and damage going on. You can delay for a while and it is Ok, but don’t push it too far, you are just asking for bigger damage and bills a little later, IMHO. It is like the laws of physics, if you try to get around them, they will smack you back.
Jake
01 XLT
66 GT-350