No, the slop you should be detecting is between the bull gear and the pinion.
When eying the sprocket teeth, what is your estimate of the movement? There should be some. Not something I routinely measure about 1/4 to 3/8 inch or so is what I'm thinking for a reading off the sprocket teeth and still be ok. Got one I can go check.
Don't panic yet:)
Is there anybody near you that might be able to lend some over site to what you are doing? Pretty hard to do it all via remote;)

I'll check tonight. I'll get back to you this evening. No qualified 9U mechanics around here that I know of. Just me. Yeah right Ha Ha Ha!

Also, as a next step, clean up the sprocket and hub splines and put the sprocket back on (without pressing) and measure where it comes out compared to that diagram I sent you. If it slips on beyond spec. then we know it's a no go. If it looks like it will make press and still stay in range it may be usable. The splines don't look terrible but I can see the wear step on the inner end of the hub.

In the drawing you sent me, is the thing labeled nut the large nut that I uncranked pushing off the tapered bearing? So I would put the sprocket back on and then recrank the large round nut- then measure?

That is correct:D

Well, my thinking was way off on that one:rolleyes: Went out and measured the back lash on the final gears of my well used parts D6 and for what I felt was good is actually 0.026 on one side and 0.028 in. on the other as measured at the tooth tip. Guess you'd have to get near 0.040 in. or so to get concerned. Don't recall seeing a spec for this.

Wow you've got good eyes! I did some measurement.

On the sprocket hub- I left out the tabbed locking washer and used a feeler gauge to measure between the hub and nut. I get right in the ballpark of
.020.

On the backlash- Without doing any measurement (going by eyeball) it is less than 1/4 inch. It sounds like I need to do some closer investigation if you are getting .026 or .028. After dinner I will go back to the shop and push the sprocket all the way forward hold a feeler at the tip of the sprocket and then move it. I assume that's how you did it.

Well I've got a whole lot more backlash than you. With my dial indicator at the top of the sprocket tooth I'm getting about .086

I don't follow your measurement procedure.
What we're looking for is the distance from the end of the splines to the face of the sprocket hub. You can use the nut to push on the sprocket but then you would have to back it off to measure. Doesn't matter if you use the lock tab or not. Is that what you are doing?

The spec range is the 0.060 to 0.190 in. so if you have 0.020 now your not within limits and pressing would only make it worse.

I measured the back lash with a magnetic base dial indicator set up.
Using a feeler gage and fixed reference will work also.

Sorry, in looking back I misquoted the 0.060 as a 0.006.

I have them.

Just junked a bevel gear housing and final drives that had a set of sprockets that was worn out on the teeth, but still in place and tight on the hubs as far as I can tell. Anyway, that set is gone, but there's others.

I could ship you some, but anything for a 9U should be available in your county Maybe

My idea on this is that if it ran while it was loose, it won't last if you press it back on. Replacing the sprocket might do it, but as OM says, a good hub AND sprocket would be a sure thing.

I'll help however I can.