98 XJ - 4.56 gear upgrade and 33" - breaking everything

Auto locker front/rear.
Just finished my upgrade from 4.10 to 4.56 in my D44 and D30 and took it out for it's first wheel this afternoon.
Busted the passenger front u-joint while crawling up a log. Didn't know they use a different size joint than the DS, so didn't have a spare so pulled the shaft, removed the old busted joint, stuck some rags in a plastic bag and shoved it into the axle tube to the seal, re-install uni-bearing and figured it was time to head home.
Got out of the trail and right up to the highway. Foolishly decided a burnout was in order. Spun the rear DS u-joint!. It of course, took the retainer straps with it and sheered off the bolts, so couldn't swap out the new u-joint.
Tried to drive home in 1wd (front driver) but got about 1km up the highway and it was just too much torque steer to drive the 60km home and called a tow truck. Defeated!

But, wtf? 4.56 aren't much bigger than 4.10 and in my 10 or so years and 6 Jeeps, I've never popped a u-joint, then today two in a row. Do the 4.56 really just require a dramatic change in driving style, or is this just really bad luck?

Here's me about 30 seconds before spinning the front pass u-joint

I run 4.56 and 37's with your same axles. I broke my strap yoke in the rear right away, upgraded to a bolt yoke and haven't had an issue sense. The axle joint was either shit luck, worn joint, or too much skinny pedal.

First its kind of good you couldn't drive it in 1wd, if you didnt install the stub shaft back into the unit bearing otherwise the wheel would have feel off too.

What u-joints are you using? I mean they break it happens....

& doing a burnout are you surprised....

blistovmhz, so much newbie in one post, and you've been registered since 2007?

Your lucky your not road kill, running hubs sans shafts had killed more jeepers.
As stated above, the shaft holds the hub together.

You didn't know the u-joints were different? Really?

Yes, upgrading to 4.56, and more importantly running 33's on the end of a D30 requires you to not wheel like an idiot

Throwing a wheel joint cap is common. The ears deform, the cap spins, and shucks the C-retainer. Lots of solutions posted here; modify your shafts to accept full circle, tack the caps on to prevent spin, or upgrade to alloy full circle clips that do a better job of taking the extra stress.
Some folks carry spares with the hub attached so that it's an easy swap.

On the rear, are you sure you didn't bust or deform the rear yoke?
There are two small cap retainers cast into the yoke that the joint fits between. If the rear joint is not settled between those when you install the rear joint, you will shuck a cap and all heck breaks loose.

A final word on treating your beaste bad. Automatics are a fantastic thing, but couple their torque multiplying capabilities with deep gears and big tires, and you are guaranteed to break things if you drive it poorly.
If you expect to drive to the trail, wheel, and drive home again without having to fix stuff, you should drive it like you want to drive it back home again.
I'm not saying that you can't have fun, I'm saying that you can't beat it like a red headed step child and expect it to take you home again.

FWIW, I run my D30 locked on 33's with stock shafts.
Yes, I've totaled the shafts before (always the drivers side). It doesn't happen often as I generally recognize the situations which will lead to failure.
But when I do, I stop screwing around, pull just the inner shaft, and call it a day.

-Ron

burnout, on pavement, with a locker...thats going to lead to bad things. In my experience the autolockers seem to put way more shock load on the driveline than others. Im always trying to be careful while turning because just a little bit more throttle changes the axle from 1WD to full lockup and if your on the throttle when that happens its a heck of a lot of shock through the driveline

Upgrading one part often exposes weaknesses in other areas. The front U-joint was probably already on its way out since you really didn't do anything hard core to break it.

The DS joint was possibly do to axle-wrap. Perhaps your springs are wore out and let your axle rotate a bit causing the DS to bind and break. I would check that out when you get the DS back in.

I'm running 4.88's in a D30/ D44 combo on 35's. Have yet to blow a u-joint in the axle. I did kill a DS joint due to axle wrap many years ago (on 33's). Better springs have kept that from happening again.

jrowell said:

Upgrading one part often exposes weaknesses in other areas. The front U-joint was probably already on its way out since you really didn't do anything hard core to break it.

The DS joint was possibly do to axle-wrap. Perhaps your springs are wore out and let your axle rotate a bit causing the DS to bind and break. I would check that out when you get the DS back in.

I'm running 4.88's in a D30/ D44 combo on 35's. Have yet to blow a u-joint in the axle. I did kill a DS joint due to axle wrap many years ago (on 33's). Better springs have kept that from happening again.

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Axle wrap is probably the answer (or at least part of it) to the rear DS joint. I had to add a leaf to the rear the other day, and it's not quite the same arc as the rest, so it was slapping a bit and I suspected before I even drove it, that I'd be wrapping a bit more than I like, but I figured I might as well test it and see what happens. I took it easy on the highway and gave it hell off-road, but I really wasn't expecting it to wrap far enough to snap the u-joint and pull a chip off the yolk Now I know.

WB9YZU said:

blistovmhz, so much newbie in one post, and you've been registered since 2007?

Your lucky your not road kill, running hubs sans shafts had killed more jeepers.
As stated above, the shaft holds the hub together.

You didn't know the u-joints were different? Really?

Yes, upgrading to 4.56, and more importantly running 33's on the end of a D30 requires you to not wheel like an idiot

Throwing a wheel joint cap is common. The ears deform, the cap spins, and shucks the C-retainer. Lots of solutions posted here; modify your shafts to accept full circle, tack the caps on to prevent spin, or upgrade to alloy full circle clips that do a better job of taking the extra stress.
Some folks carry spares with the hub attached so that it's an easy swap.

On the rear, are you sure you didn't bust or deform the rear yoke?
There are two small cap retainers cast into the yoke that the joint fits between. If the rear joint is not settled between those when you install the rear joint, you will shuck a cap and all heck breaks loose.

A final word on treating your beaste bad. Automatics are a fantastic thing, but couple their torque multiplying capabilities with deep gears and big tires, and you are guaranteed to break things if you drive it poorly.
If you expect to drive to the trail, wheel, and drive home again without having to fix stuff, you should drive it like you want to drive it back home again.
I'm not saying that you can't have fun, I'm saying that you can't beat it like a red headed step child and expect it to take you home again.

FWIW, I run my D30 locked on 33's with stock shafts.
Yes, I've totaled the shafts before (always the drivers side). It doesn't happen often as I generally recognize the situations which will lead to failure.
But when I do, I stop screwing around, pull just the inner shaft, and call it a day.

-Ron

Click to expand...

I very well may have also damaged the rear pinion yolk during the gear swap. For some reason, I just had really bad luck getting the old outer bearing on (turns out it was a manufacturing defect) and i had to hammer pretty good on the pinion yolk to drive the bearing seated on the shaft. Yes, I know, not ideal, but I work with what I've got and I absolutely don't mind learning the hard way.

MrShaft696 said:

First its kind of good you couldn't drive it in 1wd, if you didnt install the stub shaft back into the unit bearing otherwise the wheel would have feel off too.

What u-joints are you using? I mean they break it happens....

& doing a burnout are you surprised....

Click to expand...

I'm not sure what you mean by the stub shaft holding the unit bearing in? It's not supported by anything other than the unit bearing. Can you elaborate?
I've driven heaps of Jeeps home (slowly) without the shaft installed, and even wheeled pretty hard, and never lost a wheel. I can't think of any reason the stub would help support the wheel at all.
Also, I do burnouts and launch starts all the time I bomb parking lots whippin' shitties every time it rains, with 33's and always manage to stay well under control and never bust anything.



Yes, I know sounds like a newbie mistake, and I suppose it sorta is as this is my first experience blowing out a u-joint (as I said, i've damaged a few, but always catch it before it lets loose), so now I've got two breaks under my belt and I know a bit more. Still though, I've beaten this most recent Jeep harder than any of my other Jeeps and last nights trip was extremely mild compared to a normal day out. That front joint let loose climbing a stump (pictured in the OP), backwards (rear driver tire up) in sand. There was almost no torque at all, no traction whatsoever on the front and my wheels were pointed straight. All I can think is the joint was already on it's way out and it was just coincidence/bad luck that's where it let loose.
The rear DS U-joint had lots of reasons to let go (axle wrap and possibly a bad yolk).

All that said, I've got a second question.
I know it's a good idea to design our build so that the weakest link is the easiest to change on the trail. That seems like a u-joint is a good candidate. I'd definitely rather change a u-joint (which I can carry a box of) than change an axle shaft (which I can't really carry 4 of) or an entire drive shaft (which again, I don't want to carry on day trips).
I swapped out all the u-joints about two years ago (and the rear ds joint was swapped a few days ago), but probably didn't choose very good joints.
Would it make sense to upgrade the u-joints to even something like a spicer 760 (they're probably 297 in the front), or will this just make an axle shaft failure a lot more likely?

the hub is 2 pieces pressed together. thats why the shaft has a nut on the outer end, and isnt just splined to fit.
i've seen relatively new hubs seperate on street driving so it is just a roll of the dice really. i wouldnt do it.
overall it sounds like you had a combination of unexpected breakage mixed with a litle bit of stupid.
it's not the gears, it's the wear and tear on the rig and the driver's input.

it doesnt make sense to say you would rather replace an axle u-joint on the trail, than swap a shaft..... you have to pull the shft to replace the joint...
get some spare shafts and strap them together under the rear seat..... cheap insurance and a no-brainer for anyone who ventures out into the woods driving over logs.

blistovmhz said:

Would it make sense to upgrade the u-joints to even something like a spicer 760 (they're probably 297 in the front), or will this just make an axle shaft failure a lot more likely?

Click to expand...

they are esentially the same thing, just a different spicer part #

Unitbearing is supported by the stub shaft. You may have been lucky in the past but I wouldn't recommend doing it anymore. I rember a kid on jeepfourm drove like that and put his jeep right into the guard rail when the hub separated.

blistovmhz said:

I've driven heaps of Jeeps home (slowly) without the shaft installed, and even wheeled pretty hard, and never lost a wheel. I can't think of any reason the stub would help support the wheel at all.

Click to expand...

You can run without an inner shaft but if the outer shaft is removed, nothing is holding the unit bearing together except friction.
Hate to admit this but many years ago, when the XJ was new to me, I made the mistake of running without the front shafts while tracking down a strange noise in the front axle. It made it down the street about a block before the first hub bearing separated and was barely able to get back home.'
The other hub popped entering the driveway. Had no idea that the hub bearings were just pressed together...now I know. lol
Well, at least I got two new Timken hubs out of it.
I carry a outer stub, with a hub, for use if an axle breaks, along with a plug for the axle, for fluid retention.

I bought RCV's when I locked the front axle and I was on 32s/4.56s. Cracked the caps on both front axle u-joints the first run after I installed the locker, so I already had the RCV's on hand to replace them. Best driveline decision I ever made.

Only issue I ever had with the rear DS was wearing out u-joints, probably due to axle wrap. Never really broke one though. Always carry extra straps and bolts with you, or get the machined straps instead of the crappy stock ones.

Ah yes, running without outer shaft makes sense, but I only removed the inner which does nothing.

As for straps vs. ubolts, I'm just looking into this. Seems like the ubolts are a better idea, as if they do let loose, you still drive home if you've got a spare joint and ubolts. Looking for parts now.

blistovmhz said:

Would it make sense to upgrade the u-joints to even something like a spicer 760 (they're probably 297 in the front), or will this just make an axle shaft failure a lot more likely?

Click to expand...

You might want to re-read my post. The failure point is not actually the joint, but the shaft. Preventing the cap from being spit out is the key.

Once the cap spits, it's a fast road down hill from there, I have even seen the lower ball joint separated by the mashing axle metal.

-Ron

I've been running 4.56's since 2006 with 33's and broke one stock D44 shaft, alloy shafts front and rear now + u bolt yokes, never had an issue.

Full circle clips on the caps. I've been spotting someone and watched a cap pop out, got them stopped before breakage occurred. You can modify the stock shafts with a cutoff wheel to give the tiny bit of extra room behind the joint to put in a full circlip. Some guys tack weld them, but I like grease to stay in the joint.


Also, carry a 2wd stub shaft and spare unit bearing. <- this is why I haven't broken a front shaft yet.

sunburned said:

I bought RCV's when I locked the front axle and I was on 32s/4.56s. Cracked the caps on both front axle u-joints the first run after I installed the locker, so I already had the RCV's on hand to replace them. Best driveline decision I ever made.

Only issue I ever had with the rear DS was wearing out u-joints, probably due to axle wrap. Never really broke one though. Always carry extra straps and bolts with you, or get the machined straps instead of the crappy stock ones.

Click to expand...

I was just going to ask about RCV's.
The question in my mind, is what is going to break first, and what do I WANT to break first. With the RCV's being so much stronger, where does that move our weakest link? R&P presumably? Anyone know/have experience?

This is always the thing. I don't mind throwing a u-joint at all. It takes me all of 20 minutes to swap out a front u-joint, and 10 minutes to do a DS joint. I hear that when you spin a joint, you're almost certainly going to destroy an ear as well, in which case the spare joint is pointless, but I really don't want to carry trail spares of all the stuff I need to get home. I already have 100lbs of tools (enough to take apart anything on the Jeep), and I can limp home with only one spare rear shaft (the short shaft is just long enough to limp home on the long side), but carrying two front shafts, one stub, and a uni-bearing, seems like a lot of weight.

Is RCV the answer (I ask now that I've already ordered a tonne of new u-joints), or will that just move my weak point somewhere I can't trail fix?

so back to the matter at hand, my opinion try some or one of the following, full circle clips on the u-joints, tack the caps in place, use IRO "almost alloy" kit, or upgrade the axle shafts. Not sure what fits in your budget. I tack my caps in so they dont walk....& wheel with spares...

MrShaft696 said:

so back to the matter at hand, my opinion go with full circle clips on the u-joints, tack the caps in place, use IRO "almost alloy" kit, or upgrade the axle shafts. Not sure what fits in your budget. I tack my caps in so they dont walk....& wheel with spares...

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Budget isn't a big deal, but neither is swapping parts on the trail if it means saving myself 500lbs in axles
The RCV's look good, but as I mentioned, I'd much rather break a ujoint than a pinion.

With chromo shafts, am I still just as likely to bust an ear when I lose a u-joint?


I did take a look at the exploded u-joints and they don't look like they were spinning. Just tore the joint in half. Hoping the ears are still good. Didn't see any deformation or obvious damage, and I was crawling when I broke the front, so I stopped before the axle would've had a chance to spin around even half a rotation.

blistovmhz said:

Budget isn't a big deal, but neither is swapping parts on the trail if it means saving myself 500lbs in axles
The RCV's look good, but as I mentioned, I'd much rather break a ujoint than a pinion.

With chromo shafts, am I still just as likely to bust an ear when I lose a u-joint?


I did take a look at the exploded u-joints and they don't look like they were spinning. Just tore the joint in half. Hoping the ears are still good. Didn't see any deformation or obvious damage, and I was crawling when I broke the front, so I stopped before the axle would've had a chance to spin around even half a rotation.

Click to expand...

i would rather break the joint or shaft before the pinion as well....

were they factory original joints? or replacements? use good u-joints like spicer or other good non-servicable joints...