Rear wheel bearing? - 99 Suburban C2500

[92GMCK2500]

On the C-clip semi-float axles like Pinger's 9.5" ring-gear unit, in-and-out play on the axle shafts is common. I'm not saying it's desirable.

The C-clips can get worn, the ends of the axle shafts can get worn, and the pin through the differential housing is often worn.

I'm thinking that with G80 or other "posi" or "LSD" differentials, excessive clutch wear can cause the axle shafts to float in 'n' out, because the side-gears in the differential have excess play due to the reduced thickness of the worn clutches.

While too much side-play on the axle shafts isn't good, it's not a huge problem until there's so much play that the C-clip falls out. Then the axle shaft works it's way out of the housing, and into the car in the lane next to you. Eventually, the wheel breaks off the shaft or the shaft bends, and either way you've got a 3-wheel vehicle.

I'd expect the service manual would have specs for the amount of axle side-play...but I've never noticed them.

I've got a couple photos, but they're not ready for publication yet. Maybe tomorrow. Maybe not--gotta cram an alternator onto a Ford Fookus 2.0L, and I've been putting that off since Sunday.

Cheers.

I did search briefly in the manual, as did Pinger, but no dice yet.

Pinger mentions 0.2" or 5.1 mm as the C clip thickness. I have the old ones out in the garage somewhere, Ill try measure them next time I am out there

 

[92GMCK2500]

I found another GMT 400 forum thread where it said 1/4'' was OK!

I'll check the GM manual later for a figure.
My concern (one of them!) is what will happen in the MOT (annual safety inspection) test. Generally, any movement at the wheel will be attributed to a defective wheel bearing and fail the test.

Ahh inspection, that's a bummer. No testing where I am at, just my own perfectionism to worry about

 

[stutaeng]

I've got a 2015 12 bolt 9.5" G80 axle I'm working on currently. I believe the carrier and some other stuff is similar or same to the older 14 bolt/9.5". I didn't recall having a lot of play in/out of the axle shafts when I tore it down, but I didn't really check. The C-clips have tiny bit of wear, just enough to catch your fingernail. When I put the C-clips on the actual axle shaft groove though, there wasn't much slop there. I don't believe you can get much thicker C-clips on this one.

I was looking into the actual differential and at that center block. Maybe some shims can be inserted there against the axle shaft end to reduce excessive slop, but I'd be curious what the specification even is. I was thinking of taking more photos, but got sidetracked, just got this one of the C clips...

What is the actual term for this? Axle end play?

On a different note: On the 14 bolt 10.5" full float version (or any full float for that matter), that axle end play is zero, correct? The axle shafts are bolted directly to the hubs and don't get captured with the C-clips.

 

[JWOK]

I found another GMT 400 forum thread where it said 1/4'' was OK!

I'll check the GM manual later for a figure.
My concern (one of them!) is what will happen in the MOT (annual safety inspection) test. Generally, any movement at the wheel will be attributed to a defective wheel bearing and fail the test.

Play in a C-clip axle is common like already stated, but 1/4” is definitely not OK. The clips are retained by a step in the differential side gear whose depth is approximately equal to the thickness of the C-clip (the differentials I can remember off the top of my head anyway and I don’t recall the 9.5 being any different). Play equal to the thickness of that clip would allow it to fall out and release the axle shaft. I don’t recall a spec, but I personally wouldn’t be concerned about 1/16”. As stated already, wear on the center pin at the point the axle shaft contacts is common. G80 is difficult to check wear on side gears, but pin is easy to remove and check.

Edit: @stutaeng - correct on 10.5”, play is not related to the axle shaft. Good pic of worn clips!

 

[92GMCK2500]

A few members have noted a small amount of end play or axial movement (in & out) is common on these trucks. Do not exceed the C Clip thickness dimension!

I will definitely recheck mine just to be sure!!

 

[Pinger]

You have to think of how a c-clip works. What limits its movement is the pinion cross shaft that holds the spider gears in place. If you're pulling the rear axles, you pull the pinion cross shaft first, and that alone is what allows you to push the axles in and drop the c-clips out. Nothing but the pinion cross shaft limits the movement. You can check the ends of the axles and the pinion cross shaft for wear, but a significant speed differential between the axles only occurs when you're turning.

'Nothing but the pinion cross shaft limits the movement' - in the inward direction only - yes? Outwards, the C clip bears against the pinion that the half shaft is splined into?
If I've got that right inward movement would be limited by the (removable) cross shaft even if the C clips weren't there. (Obviously, the C clips have to be there to prevent the half shaft walking straight out of the axle tube in the opposite direction).

 

[Pinger]

I can see how wear can occur during tight turning (which I have to do - particularly reversing uphill). Is that possibly why I have play. It is on the wheel that is on the outside of the turn - the inner one is barely turning.

I'm kinda concerned that once there is play, then the hammering will worsen it.
Are these the pinion cross shafts here >>

1999 CHEVROLET C2500 PICKUP 5.7L V8 Differential Cross Pin | RockAuto

RockAuto ships auto parts and body parts from over 300 manufacturers to customers' doors worldwide, all at warehouse prices. Easy to use parts catalog.

www.rockauto.com

 

[Erik the Awful]

Yup. Re-reading the thread shows me my reading comprehension and logic took a little while to wake up this morning.

The cross shaft limits inward movement. The spider gears and c-clips limit outward movement. A worn c-clip or spider gear could also allow slop.

 

[92GMCK2500]

Interesting. Replacing my C clips reduced the end play dimension for me. I didn't measure but it was visually noticeable, I compared before & after videos which helped determine.

Didn't check check the cross shaft but maybe replacing that would reduce end play even further...

 

[JWOK]

'Nothing but the pinion cross shaft limits the movement' - in the inward direction only - yes? Outwards, the C clip bears against the pinion that the half shaft is splined into?
If I've got that right inward movement would be limited by the (removable) cross shaft even if the C clips weren't there. (Obviously, the C clips have to be there to prevent the half shaft walking straight out of the axle tube in the opposite direction).

Correct, pin limits inward movement while C-clip acting against side gear limits outward movement. I have seen one diff that I can remember with chewed up mating surface between gear and diff case, but not common in my experience. I have seen broken pins and broken retaining bolts cause problems as mentioned by @HotWheelsBurban which could require a special drill bit to remove.

You can check the ends of the axles and the pinion cross shaft for wear, but a significant speed differential between the axles only occurs when you're turning.

Don’t forget the heavy right foot and one-legged burnouts. We have probably all been there.