80 rear end noise - got a spare diff?

[Romer]

You said re-tubed and balances, what about the Joints. Mine seemed fine when cold but had an issue when warm. How is the Yoke?

My suggestion, before all that. Borrow someone elses rear drive shaft just to be sure.

You can come on down to my house take it off, drive around a bit and then you can put it back on.

 

[60wag]

I might take you up on that. Is yours a double cardan shaft?

 

[Romer]

I might take you up on that. Is yours a double cardan shaft?

Nope

 

[60wag]

As I continue to obsess over the noise, I'm pretty sure its not the driveshaft. I'm collecting rebuild parts and will be pulling the diff out one of these weekends. I was digging around on MUD and found a link to this guys site, ZUK. One of the writeups had an interesting comment that mentioned a whistling noise. http://gearinstalls.com/rob2.htm Oddly, I too have noticed a significant whistling noise. I had written it off as an exhaust noise but now I'm wondering if its actually the diff. Maybe some of the other whistles attributed to the removal of the resonator are actually gear noise? I'm hoping to find a chewed up carrier bearing when I get the thing out. Stay tuned.

 

[subzali]

IIRC, a basic Cruiser diff should work in the rear of your 80 Bruce. It seems like people swap the 80 series e-locker diffs into 40s etc., so I would imagine it would work the other way around, maybe?

As long as the ring and pinion have been wearing together since new, I don't believe they should have any noise just by getting installed in a new carrier. But I don't know?

Before pulling the rear diff, maybe you could put locking hubs on the rear end (and unlock them) to keep the rear from spinning as you drive in front wheel drive down the road.

 

[60wag]

So I finally pulled the pumpkin and found what I hope is the problem. The first pic is the forward drive side of a buggered tooth on the ring gear. 2nd pic is the reverse side of the same tooth - yes that's a crack. There is also a pretty noticeable scuff on the tooth behind it. What's wierd is that all of the other teeth look fine. Do you think this is an impact failure or a manufacturing defect?

I tried a bit of prussian blue on some teeth to check the engagement pattern. There's probably still too much gear oil on the pinion to get a good check but it didn't look too bad. pic 3 and 4 are the blue test.

I've got all the rebuild parts collected including new bearings and seals. The one thing I don't have is the big diff gasket. I know some folkes prefer to leave the gasket out and seal it w/ rtv but I was surprized how thick the stock gasket is - 0.020" compressed. I'm wondering if that thickness could possibly impact the squareness of the axle fit in the diff?

 

[60wag]

And some measurements to add.....

The ring gear backlash is 0.009" - not too far out of spec, but it is out.

Now the ring gear runout measured on the flat side opposite the teeth, is 0.035". Wow! Thing is really tweaked. What's also odd is that it is flexed/bent towards the carrier mounting surface, the backside of the gear. Maybe the damaged tooth relieved some stress and the thing sprung out of flat? I hope the carrier isn't messed up.



edit..... Rebuilding this one isn't an option unless can find a replacement carrier housing. The carrier is cracked between the ring mount flange and the body of the housing.

 

[subzali]

Yikes - well just be glad that it didn't blow up on you. My friend's CJ just had has carrier break in half and it locked his rear axle solid (luckily he was in a parking lot moving slow). Land Cruisers always wait until they know they are safe to let loose or wait until you have the time to check them out

It sounds to me like a new carrier and ring and pinion are the safest bets - wonder what would happen to make everything tweak/crack like that?

 

[nakman]

Wow, sorry Bruce guess you were right all along.. can you see any marks at all on the pinion gear? I wonder if someone tried to ram it into gear at high RPM's, or did a reverse to drive move, or something like that.. can't really think of how else that could happen.

But I believe I've got a good used R&P, let me know if you want it.

 

[60wag]

I've got a new carrier (case) on order from CruiserDan. I'm actually surprized that its available. It should be here next week. Hopefully it'll fit properly without needing to change the bearing shims.

As for how it broke..... As mentioned above, the noise was present when I bought the truck. Keep in mind that it wasn't a loud noise, just a subtle one that sounded like a tire needed to be balanced. When I got the truck, I got a folder full of service records. Most of the receipts were oil changes, brake jobs and other regular maintenance. The one reciept that was odd was for "replace rear axle." There wasn't any body work or other repair work to indicate an accident so I just wondered what happened to the original axle. Anyhow, I'll bet my current axle came out of a truck that was in accident and that is what chipped the ring gear and cracked the carrier case. I've gone over the rest of the axle housing and can't find any damage. It tracks fine, the brakes are wearing evenly. What's funny is that the pinion seal wasn't leaking at all.

Thanks for the offer on the gears but I'm all set on parts - hopefully.

 

[60wag]

So I'm finally back in 4 wheel drive. I got the diff reassembled and installed and after 20 miles, so far, so good. No noise, no leaks. Hopefully its the last time I get to see the inside of the rear end. It was a pain to do but was quite educational - way more difficult than a simple ARB install. I had to reshim the pinion and the carrier bearings to get the thing in spec. The pic below is the original case with the cracked flange.