Can I swap the tranny out of my 95 Chevy silverado 2wd 5.7 litre motor with one out of a 99 2wd silverado

No

You could stop at a good transmission shop and ask that question. Some GM transmission's have stayed the same for years. I have a Suburban trans in my '89 Caprice. Had to only shorten the Caprice's driveshaft at a driveshaft place. The trans bolted right up even though both vehicles had different size engines and transmissions.

The older one in the caprice is most likely a 700r4. It's hydraulically controlled. There were design changes but as long as you hooked up the detent cable you were good. In 92 they became the 4l60e which is electronically controlled. And the way they were controlled varied between different years. The early ones changed the most. The key with this question of a 95 trans is obd1 and the 99 is obd2. They had completely different computer systems. The trans will physically bolt in place but it will be in limp mode and most likely stay in 3rd gear