Pinion threads destroyed :(

Pinion seal was leaking, and outer pinion bearing was loose on my XJ d44 rear. Rear would howl on acceleration and deceleration. This is something I'd normally leave till it just blew up, but figured I might save some money by fixing it before it blew up my gear set and carrier and all the bearings. Finally decided to strip it down and get it all setup properly. Whoops.

Pinion nut came off just fine, got the seal out, pulled the carrier, put the nut back on 5 or 6 threads and gave it a single light tap to pop the pinion out. Punched the old outer race out, installed the new one, put the pinion back in, new bearing on, thrust washer, yolk, and pinion nut. Pinion nut wouldn't go on easily more than 5 or 6 threads .
Tried a brand new pinion nut as the pinion threads didn't seem destroyed, but the new one was even tighter.

Found a few threads on the pinion were a bit squashed, so hit the threads with a thread file for a LONG time which didn't really seem to be working, but the new nut went on with only minor resistance, about 3/4 of the way before it stopped moving easily, so I tried to back it off. Nope. Tried turning it right and left a few times but it wouldn't budge. Ended up taking a 3' snipe to back it all the way off, with my 200lbs reefing on the snipe while holding myself down with the leaf.

First 5 or 6 pinion threads are completely gone at this point.
Is there anything I can do to get this back together safely, without having to install a new R&P and go through the entire setup?
I figure I might be able to chop the with the bad threads off and still have enough to get full engagement, but I figured I'd ask here before doing something stupid.

it was fine until you attacked it with a file. Pinion nuts are deformation locking nuts, they're supposed to be tight going on when they get past the meat of the nut. That's also why you're not supposed to reuse them.

I'd put it back on, and if it goes on without cross threading and holds torque not worry about it. If it pulls the threads you're replacing the pinion, no way around that.

Yep... strong recommendation to hit the threads with a wire wheel before reassembly and always use a new nut. This is why, unfortunately.

What ratio? If 3.55, you should be able to pick up a used set for quite cheap on here, hell a friend of mine ninja-stashed a set in the back of my MJ at a wheeling run a few years back just to see how long it'd take me to notice them bouncing around between the spare axleshafts and shit. If they hadn't gotten destroyed already I'd just mail em to you.

kastein said:

Yep... strong recommendation to hit the threads with a wire wheel before reassembly and always use a new nut. This is why, unfortunately.

What ratio? If 3.55, you should be able to pick up a used set for quite cheap on here, hell a friend of mine ninja-stashed a set in the back of my MJ at a wheeling run a few years back just to see how long it'd take me to notice them bouncing around between the spare axleshafts and shit. If they hadn't gotten destroyed already I'd just mail em to you.

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Sorry, I forgot to mention. They're 4.10 currently. There's no chance the nut will go back on without cutting off the end.

That said, I'm running 33" tires and I've heard going to 4.56 will net me a lot more power and possibly even a bit better fuel economy. Is this generally true?

Also, if I do take this as an opportunity to re-gear, the previous owner of the axle said they're Thick cut gears. I can't find a lot of data on this, but from what I've found, thick cut are usually out of a rubi d44, and requires a different carrier offset. How can I check which carrier/ring I've got on there, to make sure I order the right set?

Also, will both my XJ d44 and d30 both gear to 4.56?

blistovmhz said:

Sorry, I forgot to mention. They're 4.10 currently. There's no chance the nut will go back on without cutting off the end.

That said, I'm running 33" tires and I've heard going to 4.56 will net me a lot more power and possibly even a bit better fuel economy. Is this generally true?
yes, your auto trans will thank you as well.

Also, if I do take this as an opportunity to re-gear, the previous owner of the axle said they're Thick cut gears. I can't find a lot of data on this, but from what I've found, thick cut are usually out of a rubi d44, and requires a different carrier offset. How can I check which carrier/ring I've got on there, to make sure I order the right set?
You'll need a set of calipers to measure the ring gear offset and your current ring gear thickness
Also, will both my XJ d44 and d30 both gear to 4.56?
yes

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4.56 is the lowestI'd go with a d30, 4.88's aren't strong enough. Chances are if you have thick cut gears that means it was a 3.xx carrier that someone regeared to 4.10 and didn't want to buy a new carrier. I'm not sure if thick 4.56's are available, if not, you'll need a new carrier with the proper gear break. I think it's 3.73 and up in a d44, but I didn't go looking so that's probably wrong.

87manche said:

4.56 is the lowestI'd go with a d30, 4.88's aren't strong enough. Chances are if you have thick cut gears that means it was a 3.xx carrier that someone regeared to 4.10 and didn't want to buy a new carrier. I'm not sure if thick 4.56's are available, if not, you'll need a new carrier with the proper gear break. I think it's 3.73 and up in a d44, but I didn't go looking so that's probably wrong.

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How do I actually confirm what type of gears/carrier I've got?
Previous owner said both front and back were thick cut iirc. They do look thicker than the gears in my previous jeeps, but I may also just be crazy.

If they're thick gears, where would I find replacements? I searched all over and all I could find was the rubi gears being referred to as "thick cut".

FYI, here's my d44 rear.

I don't know how you'd know without measuring a set of gears of the same ratio for the same diff that is known to be either thin or thick cut.

The real telling way to check this is to measure what's called the deck height of the ring gear carrier. Here's a page that describes this and gives specs for a variety of diffs including the dana 44: http://www.differentials.com/technical-help/carrier-breaks

As you can see it's a fairly significant difference between deck heights, 0.320" for a dana 44, so setting it upright on a table and using a tape measure from the table to the ring gear mounting surface will tell you which carrier you have.

If they are thick cut, ...and they look as though they are to me.. and being they are 4.10s then they are likely stock rubicon gears

Digger87xj said:

If they are thick cut, ...and they look as though they are to me.. and being they are 4.10s then they are likely stock rubicon gears

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If that's the case, what do I need to look for in a new gear set? I can't find anything labeled "thick cut" for a d30, but from what I recall, previous owner said both front and rear were thick cut.

If they are from a rubi, that means I've got the rubi carrier as well with the rubi offset for the thicker gears yes?

AFAIK the D30 never had a thick cut offered. Rubi thick gears are only D44s, as the Rubicon didn't have a D30

Thick cut means they will mount onto a 3.73 and lower carrier. Yours is not a rubi carrier as they were full case lockers.

Cool. Well then I'm assuming the front will just be a regular , straight cut , 4.56 gear, and the rear will be the thick cut , straight 4.56 . now just need to find someone to help me through the setup . I've got a local guy who offered to do it at $150 per axle.

blistovmhz said:

Cool. Well then I'm assuming the front will just be a regular , straight cut , 4.56 gear, and the rear will be the thick cut , straight 4.56 . now just need to find someone to help me through the setup . I've got a local guy who offered to do it at $150 per axle.

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Wait, that's not right.
Front is HPD30, which must be reverse cut.
Rear D44 ... is HP as well isn't it? (from an old XJ or something, definitely not the aluminum D44 from the ZJ/WJ.

Reverse cut for both?

rear d44 from an XJ is definitely a low pinion axle.

No, the XJ 44 is a low pinion and is NOT reverse cut.

kastein said:

rear d44 from an XJ is definitely a low pinion axle.

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Lurch said:

No, the XJ 44 is a low pinion and is NOT reverse cut.

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Yup, sorry and thanks guys. Just went out to check. Didn't make sense to me that it'd be HP on a rear.

So, standard,thick cut gears for the rear.
Reverse,regular cut for the front.

Anyone happen to have done the swap from 4.10 to 4.56 on 33's or 35's and wanna comment on fuel economy?
I've only ever heard that mpg increases slightly from 3.55/3.73 to 4.10 or 4.56, but never heard input on 4.10 to 4.56.

fuel economy? :laugh:

If I had to regear the XJ again, I would do 4.10's.
The reason is mainly durability. Rubbing a row of teeth off the ring gear one day allowed me to realize I just can't a abuse it like an OEM gear set.

It sucks when you hear the "Whirrr" sound coming out of the front axle.

-Ron

WB9YZU said:

If I had to regear the XJ again, I would do 4.10's.
The reason is mainly durability. Rubbing a row of teeth off the ring gear one day allowed me to realize I just can't a abuse it like an OEM gear set.

It sucks when you hear the "Whirrr" sound coming out of the front axle.

-Ron

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4.10's as opposed to 4.56?

WB9YZU said:

If I had to regear the XJ again, I would do 4.10's.
The reason is mainly durability. Rubbing a row of teeth off the ring gear one day allowed me to realize I just can't a abuse it like an OEM gear set.

It sucks when you hear the "Whirrr" sound coming out of the front axle.

-Ron

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I beat the snot out of 4.56's in a D30, they were beat on prior to me owning them and the current owner is beating on them harder than I did.

4.56's in a D30 is just fine.
4.56's in a D44 is not even a question.

Not quite completely off the subject but...

If you do decide to re-gear, I can attest to the combination of 33" (P285/75R16) tires and the 4.56:1 gear set. The combination gives a 10% mechanical advantage over stock which is to say that the engine will be turning 10% faster for any given road speed.

This 10% is not a calculated value, it is a measured value.

As I run a Supercharger, I had to install a F/IC to manage the larger injectors and to retard the ignition under boost. I use an AEM F/IC 8 which provides the capability to calibrate the speedometer by altering the VSS signal.

The correction required to get the speedometer to a less than .5% error is, -10.1%. thus, the 33" tire and 4.56:12 gear combination results in a 10% advantage. Whilst not exactly accurate, I am willing to live with the 1/2 percent error... Yes, this is sarcasm alright.

My fuel economy is not a good one to use for reference as it heavily depends on just how many times I get frisky on the skinny pedal. If I keep it out of boost (yah, right...) the Heep gets about 16 to 17 in town.

In boost, it gets 12. But..... It is a very fun 12......

IMO, this tire/gear combination is just about the optimal selection as it still allows for highway speeds. Also IMO, you need the mechanical advantage as soon as the rig is lifted and larger tires fitted. I know this is obvious but, larger tires take more torque to turn and lifted rigs suck aerodynamically...

The XJ is a Brick On Wheels to begin with and then, we lift them to create Brick Walls on Wheels...