Passenger front diff leak

[TangledPossum]

I've got a 21 ST which I did the actuator recall on and replaced the diff fluid. Now a year later and I noticed quite a bit of diff fluid on the bottom of the diff, passenger side. I could trace it up visually to where the axle goes into the diff. I'm assuming a seal there has gone bad.

Anyone else have this issue? Should it be relatively easy to pull the axle out, unbolt that diff cover, and replace the diff cover seal and whatever seals around the axle that slides in?

It's hard to search for this problem because every result comes back with the common actuator leak but this is the passenger side.

 

[TangledPossum]

It seems like CN1Z-7H424-B might be the part number for the axle seal that's leaking. But I can't find a proper diagram of the diff. I'd really like to see it broken apart because I'd kind of like to remove that whole passenger cover to inspect and drain the diff. My drain bolt is stuck in there and I can only remove some fluid by suctioning it out the fill hole. But I don't know how that cover seals or if it is tricky to detach.

Side note: do those drain bolts use a special socket that is not a torx? Like a torx plus?

 

[Cdubya]

You will spill front diff fluid once the passenger axle is removed so you will need to top it off. The front diff drain plug is torx. you may need a breaker bar to loosen it. Still, if you managed to loosen the fill plug, that is all you need.

 

[TangledPossum]

I did actually manage to complete this repair. I didn't remove the diff cover, only the axle and then diff seal. And I was able to remove the drain plug with a torx plus socket and some luck. I replaced it with a new plug from the dealer and new axle seal and the leak has stopped.

 

[wifeys-ST]

I did actually manage to complete this repair. I didn't remove the diff cover, only the axle and then diff seal. And I was able to remove the drain plug with a torx plus socket and some luck. I replaced it with a new plug from the dealer and new axle seal and the leak has stopped.

I appreciate you coming back to update this thread. I’m confident i can get the axle out. Is the seal easy to replace once the axle is out and was the part number CN1Z-7H424-B correct? Thanks

 

[TangledPossum]

Yes, CN1Z-7H424-B was the part number I used at the dealer for passenger front axle seal. It wasn't too bad to replace. It was definitely in there tight, but I was able to knock it loose with a flathead and hammer. Carefully to avoid scratching up the mating surface. A seal puller would have made it much easier. It's a big seal, so easy to get access to. The most difficult parts were prying the axle out, and popping the old seal loose. A large pry bar, seal puller, and seal install kit would make this whole job quite easy.

While you're there, the axle nut is supposed to be 1 time use and they're cheap, so I usually get a replacement at the dealer. And a tube of ford ptfe grease which is applied to the splines on the axle shaft when you reassemble to stop the clicking issue Explorers get.

 

[wifeys-ST]

Yes, CN1Z-7H424-B was the part number I used at the dealer for passenger front axle seal. It wasn't too bad to replace. It was definitely in there tight, but I was able to knock it loose with a flathead and hammer. Carefully to avoid scratching up the mating surface. A seal puller would have made it much easier. It's a big seal, so easy to get access to. The most difficult parts were prying the axle out, and popping the old seal loose. A large pry bar, seal puller, and seal install kit would make this whole job quite easy.

While you're there, the axle nut is supposed to be 1 time use and they're cheap, so I usually get a replacement at the dealer. And a tube of ford ptfe grease which is applied to the splines on the axle shaft when you reassemble to stop the clicking issue Explorers get.

awesome thanks for all that! and yes the axle popping has been so annoying so a good chance to kill 2 birds with one stone. thanks again. Might not tackle it right away

 

[wifeys-ST]

Thanks for the help and giving me confidence to tackle it. Wasn’t too bad at all. Hardest part for me was seating the new one all the way. I bought a cheap bearing drive / seal installer tool like you suggested but the sway bar was in my way so had a hard time driving it in. Finally decided to jack up the driver’s side which moved the sway bar out of my way and it went right in with a few good knocks. Funny, the hardest parts you listed ended up being the easy parts for me. Greased the axle splines but I’ll need to grease the others soon because they all pop.

 

[wifeys-ST]

Funny, i didn’t want to drain the diff until i was sure the axle nut and strut bolts would break loose. Ended up forgetting to drain it and made a bit of a mess

 

[Caster]

Thanks for the help and giving me confidence to tackle it. Wasn’t too bad at all. Hardest part for me was seating the new one all the way. I bought a cheap bearing drive / seal installer tool like you suggested but the sway bar was in my way so had a hard time driving it in. Finally decided to jack up the driver’s side which moved the sway bar out of my way and it went right in with a few good knocks. Funny, the hardest parts you listed ended up being the easy parts for me. Greased the axle splines but I’ll need to grease the others soon because they all pop.

You're way off on the torque specs for the lower strut bolts. I added a Traxda lift to my 25' ST in Jan. or February of this year. I had to use my big torque wrench to torque them properly.

 

[Cdubya]

Wifeys-ST, did you use a seal install kit? wondering what a. good one is. I too may have overfilled the front diff fluid. I get some seepage from the seal but waiting to see if goes away. May be doing this too. Thanks TangledPossum for the part#... I couldn't find it searching a Parts site.

 

[TangledPossum]

Glad it worked out well. 6 months ago I greased my rear axle splines and it made a lot of the clucking go away. But it's pretty much back now. I might do all 4 at aome point. But I get the feeling that the only solution may be to replace all hubs and axles to get a solid fit again and grease them all. But I don't feel that's worth it because I don't think the clicking is hurting much.

Also thanks Caster for posting the torque specs! I can't believe how high the spec is for lower bolts. I tightened mine down real good, but I might not even have hit 250. I'll need to recheck them next time the wheel is off.

 

[wifeys-ST]

Glad it worked out well. 6 months ago I greased my rear axle splines and it made a lot of the clucking go away. But it's pretty much back now. I might do all 4 at aome point. But I get the feeling that the only solution may be to replace all hubs and axles to get a solid fit again and grease them all. But I don't feel that's worth it because I don't think the clicking is hurting much.

Also thanks Caster for posting the torque specs! I can't believe how high the spec is for lower bolts. I tightened mine down real good, but I might not even have hit 250. I'll need to recheck them next time the wheel is off.

You're way off on the torque specs for the lower strut bolts. I added a Traxda lift to my 25' ST in Jan. or February of this year. I had to use my big torque wrench to torque them properly.
View attachment 32153

Thanks for sharing this. It looks like we both have information from a trusted source that doesn’t line up. I have a 2020, maybe the splined studs are different. I used this vid from FordBossMe who is very trustworthy and he was using Ford’s Oasis database for the data.

This is the second time in 24 hours I’ve seen ford information conflict. The front diff drain and fill bolts say 30ft lbs on some guides and 18ftlbs on other guides. Guess it’s up to the owner to decide. I did my driver’s side to the same 166 ft lbs a year ago and hasn’t been an issue. My wrench only goes to 150 so I like to just hit it with 150 then a real solid ugga chugga past that

 

[wifeys-ST]

Wifeys-ST, did you use a seal install kit? wondering what a. good one is. I too may have overfilled the front diff fluid. I get some seepage from the seal but waiting to see if goes away. May be doing this too. Thanks TangledPossum for the part#... I couldn't find it searching a Parts site.

not sure if this is the right tool but I used this. Worked okay. would have been nice if that bar was longer for this job. https://a.co/d/cIfaCXf figured I will probably find a lot more uses for it in the future.
And I used the cheapest 5$ seal removal tool it came out in 3 seconds on the first attempt.

 

[wifeys-ST]

Glad it worked out well. 6 months ago I greased my rear axle splines and it made a lot of the clucking go away. But it's pretty much back now. I might do all 4 at aome point. But I get the feeling that the only solution may be to replace all hubs and axles to get a solid fit again and grease them all. But I don't feel that's worth it because I don't think the clicking is hurting much.

Also thanks Caster for posting the torque specs! I can't believe how high the spec is for lower bolts. I tightened mine down real good, but I might not even have hit 250. I'll need to recheck them next time the wheel is off.

That’s frustrating that the sound is back. What grease did you use? I’ve heard different things, I just went with some stinky red bearing grease I’ve had forever.

 

[TangledPossum]

That’s frustrating that the sound is back. What grease did you use? I’ve heard different things, I just went with some stinky red bearing grease I’ve had forever.

I used the Ford Motorcraft XG-8 PTFE lube. I think I saw in the click fix youtube video that is the recommended grease from ford to fix the issue. I imagine any super thick outdoor bearing type grease would work the same.

Now to be fair, on the rears I used the trick where you don't pull the axle. Only take the nut off and slide it halfway back and it's tight in there to get more grease in. Pulling the axle would get better coverage and quantity, and I could do the inside as well if the axle doesn't go inside the diff - I'm not sure what the rear setup is like.

 

[Caster]

Glad it worked out well. 6 months ago I greased my rear axle splines and it made a lot of the clucking go away. But it's pretty much back now. I might do all 4 at aome point. But I get the feeling that the only solution may be to replace all hubs and axles to get a solid fit again and grease them all. But I don't feel that's worth it because I don't think the clicking is hurting much.

Also thanks Caster for posting the torque specs! I can't believe how high the spec is for lower bolts. I tightened mine down real good, but I might not even have hit 250. I'll need to recheck them next time the wheel is off.

Agree, its crazy high torque for what those bolts do.