Transmission Shift Noise

This is a tough one but I think your transmission is just beginning to wear out. Your S10 is now 27 years old and while the mileage isn’t excessive for a vehicle of that age, just the fact that it is so ancient (I don’t know what the equivalent of car years is to human years, but, given the stresses that vehicles have to live with it’s probably on the order of a dog, 7 years. That makes your truck 189 human years old. It’s not youngster that’s for sure.)

All kidding aside, it just sounds like parts are wearing out. More than likely, when you have it opened you’ll find the bands are living life on the edge right now. They are neither quite failing nor are they working correctly. I suspect that they are stretching far beyond whatever their limits may have been.

You do indicate you perform regular upkeep on the tranny, however, I suspect that you never had the clutches and bands replaced or, if you have had them done, it was so long ago, that you aren’t thinking about it. With that said, take your S10 to your service shop and have a trained tech take a look at your transmissions. The chances are pretty good that the problem lies there.

One other suggestion that just came to mind is this: take another look at the tranny fluid level. It is entirely possible for a transmission to read full when it is cold. Did you let your S10 warm up thoroughly? If not, then, it is more than certainly either the bands or the transmission fluid level. And, though I honestly thing the problem is with the bands, it, equally as well, could be with the fluid level.