Axle Spider Gear Play?

For reference, my truck is a 2001 DBL Cab, open diff.

The truck was geared with 4.88's prior to me purchasing it. There has been a clunk when shifting into drive or reverse since I bought it. Also, when at speed on the highway and I lift off the throttle, there's a noticeable amount of play I can feel in the rear-end. It seemed like there was play between the drive and coast side of the ring gear. Thinking that either the ring, pinion or both were misaligned, I tore it apart to check. Well, the pattern is perfect and the dial indicator showed that everything is perfectly within spec. While reinstalling the axles, I found the culprit.... The splines on the axles have TONS of play against the spider gear splines. It seems like there's no way this can be from wear. Possibly axles or 3rd member out of a different year that doesn't quite match? I would have thought that any set of Toyota splines that fit into each other would fit tight and correct regardless of year.. Hell, I don't know! Any thoughts?

Thanks!

 

Low gears big tires are super hard on axles. Might want to consider upgrading the axles.

 

Splines can wear over time, are you sure it's the spline and not the spider gears themselves that have play?

 

Damn, I guess I hadn't thought about the spider gears themselves, instead of the splines, being worn. It's hard to imagine anything being worn because it's been doing it since the truck has had 99,000 miles on it (when I got it) and there have never been any particulates in the oil.. The guy who had the truck before me was kinda an idiot, so anything is possible. Might be in the market for a new rear end! Thanks!