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Bone stock 1989 Trooper S 2.8.
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Discussion Starter · #1 ·
Question for the trail guys out there:

During the few moments when my Trooper was actually running, I tried to test the transfer case and front axle at a friends house. Sometimes, in both 4 hi and low, there is a sound/feel like a gear skipping a tooth. But very subtle. It FEELS like it’s coming from the back, but it never does it in 2 wheel drive. I swear it feels like a gear somewhere is missing a tooth. But that makes no sense because it’s NOT rhythmic. It’s not like it happens every 10 feet or something. And it doesn’t get worse.

Could I have a bad transfer case?
 

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I may be way off, but I had a weird thud sound at random times only when in 4WD, and it did sound like it was coming from the rear. Turned out to be a bad manual hub in the front. What a relief it was that replacing the hub made this go away. I hope yours is a simple solution also.
 

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Discussion Starter · #3 ·
Oddly, a bad hub as the cause keeps tickling the back of my brain. I would think that a bad gear in the transfer case would quickly lead to exploding gears.

I have the automatic hubs - which I love - but maybe they need repacked with grease or cleaned or something? Do they go out often?
 

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Sounds like a bad hub or popped circlip. You've probably seen my comment on those in your other thread, I'll leave it at that.......ed
 

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Discussion Starter · #6 ·
Is this the clip that’s the problem? It fell out when I took the hub apart.

Sculpture Art Artifact Statue Wood
 

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Yup, that's the one! And it can be a real pain to reinstall. There are usually shims behind the clip to adjust free play in the axle. So it's a quite snug fit.

The end of the axle is threaded, so you can screw-in the appropriately-sized bolt and pull on the axle while you're pushing on the clip. A deep socket, sized such that it'll fit into the I.D. of the auto hub, and clear the axle tip, might help you get an even push on the clip. You can run the axle-end bolt right thru the end of the socket.

BTW your pic clearly shows the groove for the manual hub circlip; both grooves seem to be in good shape. Be sure to test fit that clip before reassembling, to make sure it fits the groove snugly and is the right thickness, etc.

Good Luck!!
 

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Tires... make sure your TIRES are the same size and relatively new. (unless you have TOD which is more forgiving for diff tire sizes)
 

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Discussion Starter · #9 ·
Put the clip back in after crimping it a bit to make it more of a tight fit. You mentioned a bolt on the end of the axle - mine already had one in there with a concave washer on it. The head of the bolt and the inside of the hub were shiny where they touched, but not worn. Just shiny. Also, there weren't any shims behind the clip, so putting it back in was pretty easy.

It's still skipping - but less. I'm going to pop off the other hub. I suspect I'll find another clip flopping around in there. Maybe someone replaced the CV axles and didn't properly shim them? Would the lack of shims (or the BOLT) cause the problem? I wouldn't think so, but my confidence is zero right now.
 

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Sounds like a P.O. had problems with the clips popping off. They might have left the bolt in there as a way of limiting inboard movement of the axle.

I've always thought that if one had the right combination of spacer washers and shims, that the clip could be done away with. A bolt at the end of the shaft is a much more positive way of retaining the axle than that flimsy clip. All you'd need is a stack of flat washers and maybe a wavy washer, to take up the extra space in the auto hub. Then use the shims that are usually between the face of the hub and the inboard side of the circlip (or in your case buy or make some), to get the axle free play set. There'd be no possibility of the axle ever backing out of the hub. Maybe use a star washer on the bolt/axle interface, to keep the bolt from ever moving.

I bet you'll find something wonky on the other side, too. Usually, the clips popping off are the biggest problem with auto hubs. Other than the mechanism breaking or just flat wearing out, with lots and lots of use. I'm still on auto hubs after 19 years of ownership with the latest Trooper, and they still work great.

IIRC I serviced them in 2012 after doing the Big Brake Mod. Which, BTW is an excellent upgrade in the front brakes, using Gen II Trooper rotors, calipers, brake shields, and Rodeo brake hoses. Search "Big Brake" and you'll find plenty of threads on that.

Keep at it, you're slowly but surely on your way to ZuZu Expert, as you work your way thru the typical Gen I problems!

Cheers.........ed
 

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Re-reading your last post brings this to mind, re: your question about shims, I suppose if the clearance was excessive, the axle might slam in-and-out and maybe that would cause a noise, hard to say. The clearance spec is .0039" so that's not a lot.

One thing to try with the axle clip in place is to pull/push on the bolt screwed into the end of the shaft and see if there's a significant amount of play. If so, it needs to be shimmed to spec.
 

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Discussion Starter · #12 ·
Well, poo! Got my cheap manual hubs from Amazon, waited until it wasn’t raining, took apart the passenger hub…

And discovered that the splines are all worn off from the manual hub retaining ring groove out. Looks like my only option is automatic hubs until I replace the CV shafts.

And I’m still not 100% convinced it’s the hubs. For one thing, they are in perfect shape. No wear at all on the surfaces that I can see. And it FEELS like the clunk is coming from the center of the vehicle. I checked the center carrier, but it seems okay. I can move it slightly by shoving sideways on it. There is a definite loss of motion, too. It’s not just a noise.

Not sure what to do next. Go to Uhwarrie and hope it doesn’t break permanently, I guess. Because that always works out well when 4 wheeling. 🤪
 

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The main concern now is whether there are enough splines at the end of the axle to even drive an auto hub. Pretty evident that the retaining clip has been off a long time, and the axle has been pulling in when in 4WD, enough for the splines to grind themselves upon the inboard side of the hub.

You may be forced to replace the pssgr's side axle in that case. You can release tension on that side's torsion bar, then pop the upper ball joint, and there's just enough room to slide the axle out of the spindle without breaking the lower ball joint.

Heck, maybe the ball joints are worn-out already anyway. Then you can use a number of techniques and special tools (available from Autozone and O'Reilly, free rental with full-price refundable deposit). With the entire spindle out of the way, it's a ton easier to work on the axle. And as long as the inboard joint is in good shape and the "cup" too, you can do a "quick and dirty" replacement of axle minus cup.

The axle is just held into the cup with a big snap ring, so take it out, clean the cup thoroughly, grease 'er up and reinstall. As I recall, there's a snap ring that holds the cup into the diff and that would required digging further. Or maybe it's designed to pop out with greater force. I've never done it so maybe one of the other Trooper Dudes can chime in.

Anyway, think you've found your noisy problem, I'd definitely check spline engagement into the hub to make sure the axle will still drive the wheel. G'luck.........ed
 

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Discussion Starter · #14 ·
That’s the weird thing! The retaining clip was on! The driver’s side was off when I took it apart, but the passenger side was fine. I put the driver’s side clip back on, and gunned it a few times up the driveway (it needs more gravel anyway, right?), and when it skipped, I figured it had come back off - but no.

To recap: driver’s side had clip off, but the splines are perfect. Passenger side, the clip was fine, but the last 1/8 inch of splines are worn. All components of the hubs themselves look great. Both side have a bolt and “special” washer on the axles. I say special, because they sure look like they belong there.

And, I don’t KNOW that it’s an issue with the hubs. I just assumed.
John
 

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Had a friends troop doing this recently... he replaced cv joints, brakes, 4 new tires, cleaned those auto hubs and I had him not pack the autohub with bearing grease but wipe a light coat of vasoline on all of the hub parts on reassembly and his hubs don't knock anymore under load.
Now I cant say that alone is why his just work now or if its having 4 tires all perfectly matched vs 4 oddballs but it costs next to nothing to give this a try.
Read the comments in the vid also.
 

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Discussion Starter · #16 ·
Interesting. I will say that my auto hubs are not just well greased, but are FULL of grease. Thought that was normal.

I actually have to crawl up a short hill over and over today, and I have a helper. Maybe we can pin down the offending hub. From inside, the noise comes from everywhere.
 

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Discussion Starter · #18 · (Edited)
So, everyone was correct, it was the automatic hubs. Since the CV shaft was mangled on one side anyway, I cut a new groove and put a slightly smaller (25.4mm - or 1 inch) snap ring in there. Still no spacers. I'm not sure those things really exist. :)

Anyways, I punched it a few times going up the driveway with about 500lbs of cement in the back, and it did fine. We'll see how it goes at Uwharrie.

Eventually, I'll replace the axles and go back to automatic hubs. I like the convenience, and I don't need the uber strength. And, my boots are shot anyway, so the axles are living on borrowed time.

Thanks to all for your help on this.
 
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