broke a tooth in my rear differential gear box

[youngbuckwithapickuptruck]

and removing the 'center pin' lets the axle shafts slide out, yes?

I take it used spider gears would be fine
autozone charges about $200 for a set of spider gears and a replacement axle is about $200

 

[Uncle Gump]

When you pull the pin... push the axle inward and there is a C clip that might just drop out... or you remove. Then axle can be pulled from the side gear.

 

[pjtoledo]

while you're in there, now is the perfect time to replace the axle seals since the shafts need pulled to replace them.
no brake work except removing the drum.

and yes, the rear gear lubricant stinks. even when new.

 

[scotts90ranger]

Full list of steps:

-Jack vehicle up
-remove tires
-remove differential cover
-remove cross pin bolt (has 5/16" or 8mm head, either works, might take some heat with a butane or propane torch to release the loctite)
-remove cross pin
-push in on wheel studs or center of axle shaft (don't need to take off drums, but no reason not to either)
-pull C clips off inner ends of axle shafts
-pull axle shafts outward ~3" probably less is fine too, whatever works
-remove spider gears, rotate the outer gears so they come out the windows then the side gears will come out of the carrier
-install replacement spider gears and reverse steps, clean the cross pin bolt with brake clean and use some blue loctite on it

 

[youngbuckwithapickuptruck]

some pics:
1. tooth and spider gear wear
2. i thought i could wedge the tooth out against the ring gear but i dont want to damage the ring gear.
3. pinion gear has some damage, is that a significant amount?
4. visible metal shavings in my oil. significant amount?
5. time to change wheel seals. left side is driver side.

I cant get that tooth out. i was hitting it with a punch and hammer and saw it shift, but it wont come loose.
any idea what the thud noise could have been when i drove it 2miles in that condition?

are spider gears from the junkyard fine? autozone wants $200 for them and i could get a whole rear end from pick n pull for that price.

 

[Curious Hound]

Added 2 steps

Full list of steps:

-chock front tires so vehicle can't roll off jack/jack stands
-Jack vehicle up
-remove tires
-remove differential cover
-remove cross pin bolt (has 5/16" or 8mm head, either works, might take some heat with a butane or propane torch to release the loctite)
-remove cross pin
-push in on wheel studs or center of axle shaft (don't need to take off drums, but no reason not to either)
-pull C clips off inner ends of axle shafts
-pull axle shafts outward ~3" probably less is fine too, whatever works
-remove spider gears, rotate the outer gears so they come out the windows then the side gears will come out of the carrier
-install replacement spider gears and reverse steps, clean the cross pin bolt with brake clean and use some blue loctite on it
- remove wheel chocks

 

[Curious Hound]

If that wear is the worst part on the pinion, I wouldn't worry about it unless your going racing. You definitely want yo get that piece of tooth dislodged and removed from the differential. Best way would be to drive something wedge-shaped behind it, if possible. You expected metal particals. Just clean them out of there real good. Spider gears from junk yard should be fine as long as they're in good condition. And, definitely replace the seals at the ends of the axle tubes. That one side is definitely beginning to leak.

 

[superj]

another ranger with only 200kmi, looks like it sideswiped something but not very hard, you all dont think that could compromise the axle, do you?

And that axle will probably be fin, if you chose to go that route instead

 

[youngbuckwithapickuptruck]

yesterday i was working at pulling off a rear axle from a 96 ranger and noticed the internals looked like this, is this a limited slip differential?

also intuition tells me that matching a 200kmi spider gear to a 300kmi differential is bound to have some mismatched wear patterns and i wonder if it will just grenade itself in another 6 to 18mo.
idk, should i just replace spider gears or replace whole rear axle?
if i replace the whole rear axle, can i swap in my old hubshafts into the axle housing, while the drum brakes are still in one whole piece?
after watching the spider gear replacement videos a couple times, it seems pretty easy.

 

[Uncle Gump]

It's a Traction Lock... which is Ford's limited slip.

 

[Shran]

I'd pick the chunks out and run it. I've used gears that looked way worse than that... 1st and 2nd gear in my wife's transmission were submerged in water for years and had rust pits all over half of the gear, I wire wheeled those babies off and while it does make a bit of noise, it has functioned fine for several years now. I've accidently chipped teeth during removal on a couple other occasions, just knocked the sharp edge off with a flap wheel & ran it. It's not great and certainly not ideal and I would never do it on a customer's vehicle but for me it's OK.

If you replace those axle seals, check the axle shafts where the seal lip rides and make sure that there is no groove worn in the shaft... if there is, a new seal will not do much. At that point you might as well put bearings in it too. Personally I would just clean that clumpy dirty crap off and not disturb anything... if it's not puking fluid all over, it's not truly leaking

Axles will nickel & dime you to death, the last 8.8 I bought needed literally everything. Bearings, seals, brakes, limited slip clutches..... my $150 axle turned into an over $700 axle by the time it was all said and done. So I am kind of operating under "if it's not REALLY broken, don't touch it"

 

[superj]

I am on board with that. If it still starts amd moves, i run it too.


We rebuild a lot gearboxes that are very very similar to a differential in a vehicle. We dont keep the gears together because we redo so many, and have been for so long, we have seen that as long as you set your backlash and end play properly, they work fine.

But these are on gelicopters running twin turbine engines at 2500ish shaft hp. I have seen gearboxes come in with bullet holes and from crash damage helicopters and the gears last once they have their first break in and the faces are shined up. Change the fluid regularly and you will be good.

You can always pull that axle from the teal ranger and have it as a back up, though. Is good to have a backup plan

 

[youngbuckwithapickuptruck]

okay, the cross pin wont slide out. See attached pics, please.
I pulled a cross pin from a 94 ranger at pick n pull this morning and the pin just slid out from the backside. Im guessing the ring gear is closer on my version of this transmission. Do I need to hit this with an angle grinder to get it out? One video had mentioned grinding a few teeth of the ring gear.

I hit the stuck tooth in the center with an angle grinder and then i was able to knock it out. I dont know if the angle grinder made a difference. I knicked the corner of a ring gear about 2mm deep when I did this.

my only alternative to the angle grinder is a harbor freight dremel

 

[don4331]

Higher numeric, e.g. 3.73 or 4.10s gears have smaller pinion, so the ring gear gets thicker, i.e. closer to the cross pin.
You don't have to remove the cross pin, just slide it far enough to remove the spider gears - the flat ground into the cross pin should have allowed that for stock gears.4.56 might be exception, but they are unicorns.

I don't know if anyone mentioned it, but as you have an open differential, you need open spider gears. The ones from the differential with the locker won't work.

As OP has moved the axle (slid out to remove side gears), I would clean axle and inspect for a groove. As it was seeping before, moving things can set off bigger leak. Better to just fix once, than have to do it twice. The one positive - any axle from '93 to '09 fits*, so OP can always go back to the Ranger he got the gears from should he need to. (Just gets the one from the correct side).

*There would be some exceptions for FX4 Rangers with 31 spline axles, but those are rare.

 

[pjtoledo]

okay, the cross pin wont slide out. See attached pics, please.
I pulled a cross pin from a 94 ranger at pick n pull this morning and the pin just slid out from the backside. Im guessing the ring gear is closer on my version of this transmission. Do I need to hit this with an angle grinder to get it out? One video had mentioned grinding a few teeth of the ring gear.

I hit the stuck tooth in the center with an angle grinder and then i was able to knock it out. I dont know if the angle grinder made a difference. I knicked the corner of a ring gear about 2mm deep when I did this.

my only alternative to the angle grinder is a harbor freight dremel

that nick on the ring gear tooth is exactly where you grind to remove the pin. only grind that one tooth.
that happens on 4.10 ratio gears.