Gents, I bought a '17 Runabout and I don't have any service history on it. My rear axle play is 1/16" or less when I pull on the rear wheels. I know there isn't any way to know inside without a rebuild...what would you do? Stop the cruising and rebuild or is that minimal play probably worth waiting until it gets colder to rebuild?
2 factors: how much are you realistically going to drive it the next 2 months and can you afford to buy any/all parts you need or do you need to save?
If you are going to put less than 1,000 miles on it in the next 2 months and you'd have to save a bit before having enough $ for parts, then I say drive it for now, it's going to snow 10 feet soon enough. Especially if you aren't zipping around fast (always under 40 mph). Then when it gets cold you can get the rear out and rebuild it.
If you have the money to just get whatever you need (which, you can spend several hundred really fast depending on what you find) and want to drive it a lot, then just go ahead and rebuild it - it can be done in about 10 days: Fri-Sun you rip it apart and find anything and everything that you might want or need to replace. Order all parts Monday, and then after work get everything cleaned up and painted and ready for re-assembly starting the next Friday. Saturday you finish assembly and get it back in the car, and Sunday go for test drive.
That's just my 2 cents, YMMV.
The amount of end play is not an indicator of when the Babbitt will fail, only if it has or not.
What you're seeing may be caused by a missing fiber washer that usually separates the two axle ends where they meet in the middle. In a well used rear end those sometimes "go away". They're about 1/16" thick.
Do this. While you're pushing & pulling on one of the wheels, have a helper look into the differential filler hole to see if the 1/16" end play is causing the ring gear to also move 1/16". I believe if their finger is small enough, they may be able to touch the gear. If not, insert a pencil or wire until it touches the gear, (or any other part of the differential for that matter), in order to judge if the whole differential assy. is moving, or just the axles within it. If the ring gear & diff. assy. move with the same end play you're seeing at the wheel, then it's worn thrust bearings, (babbitt?). If the diff. assy. does not move side-to-side, or does so to a lesser extent, then the issue is probably a worn away fiber washer and not a big deal.
If it doesn't leak too bad at the axle ends you can put lined emergency brake in place without full disassembly - then you'll have a brake even if the babbitt thrusts fails. Modern seals can also be put in place without full teardown.
As Hal said "The amount of end play is not an indicator of when the Babbitt will fail, only if it has or not."
Here is a picture of the thrust bearings from my rear end - there was minimum end play but one was very close to complete failure -
Don't do a Mickey Mouse job when you go through it, make sure you rebuilt the driveshaft also.
Turns out, once I did the pencil evaluation suggested by Jerry, the carrier doesn't move at all when the axle gets pulled/pushed. The only part allowing play is the center fiber washer (or lack thereof). So my diff is not moving at all from side to side. I realize that doesn't prove thrust washer reliability or condition, but it doesn't indicate awful deterioration. On both axles in which I had to do rebuilds- the play got worse and worse.
Could be the axle gear is loose on the axle and the hammering on the half round keepers has worked up a 1/16 inch slop. I've seen a lot of loose axle gears.