Rear differential leaking?

u2slow

bilge rat
Joined
May 8, 2007
Posts
1,817
Reaction score
814
Location
PNW
I also feel the 10.25" crush sleeve is undersized. I have removed one that didn't crush evenly - variable height when measured. Probably a factor in that particular diff shedding pinion teeth.

Ford had revised the pinion on the 10.25/10.5 at least twice. Short, long, and finally thicker.
 

92LongBed

Registered User
Joined
Jul 16, 2020
Posts
79
Reaction score
34
Location
Spartanburg
Finally got under my truck and took a better look and went to add new gear oil assuming my rear diff case was bone dry. I got into adding 1 liter of oil and as soon as i started #2 bottle it started leaking out of the access hole. So 2 things, i'll drive around and see if any new oil slings out on my cleaned up areas to logically determine if its an active leak or it was a previous owner's problem and they fixed it (bc my rear diff wasn't bone dry) and they just never cleaned up the oily grimy mess it made.
 

rreegg

Full Access Member
Joined
Feb 10, 2022
Posts
237
Reaction score
137
Location
Puget Sound
Finally got under my truck and took a better look and went to add new gear oil assuming my rear diff case was bone dry. I got into adding 1 liter of oil and as soon as i started #2 bottle it started leaking out of the access hole. So 2 things, i'll drive around and see if any new oil slings out on my cleaned up areas to logically determine if its an active leak or it was a previous owner's problem and they fixed it (bc my rear diff wasn't bone dry) and they just never cleaned up the oily grimy mess it made.
Your post inspired me to replace the pinion seal on my rear diff this past weekend. Probably didn’t need to do it because the diff oil wasn’t that low and the gear oil is so thick it’s not gonna drain fast anyway. It’s still gonna leak but is rust protection
 

92LongBed

Registered User
Joined
Jul 16, 2020
Posts
79
Reaction score
34
Location
Spartanburg
so after driving about 25 miles with newly added differential oil i checked my truck and its dripping from the actual u joint? i figured it would come out of the seal to the right into the diff case. i'm not exactly sure how to proceed do I still need to replace the pinion seal or is this a different part that needs replacing (u joint)
 

Attachments

  • u joint leak.JPG
    u joint leak.JPG
    323.4 KB · Views: 14

rreegg

Full Access Member
Joined
Feb 10, 2022
Posts
237
Reaction score
137
Location
Puget Sound
so after driving about 25 miles with newly added differential oil i checked my truck and its dripping from the actual u joint? i figured it would come out of the seal to the right into the diff case. i'm not exactly sure how to proceed do I still need to replace the pinion seal or is this a different part that needs replacing (u joint)
it's possible the diff oil is just dripping from the ujoint depending on terrain, but there's grease/lube in the u-joint too that could be 'dripping'. when doing the pinion seal i also relplaced that u joint as well since it was worn (and maube a cause of the pinion leak? who knows).

happy to help with any q's or send relevant youtube vids
 

DaveBen

Supporting Member
Supporting Member
Joined
Sep 29, 2010
Posts
1,915
Reaction score
632
Location
Ukiah, Ca
There are only two items connecting to the u-joint; the driveshaft and the rear end. The rear end has lube in it and the driveshaft does not. Not too hard to guess. It looks like the pinion seal may be bad.
 

92LongBed

Registered User
Joined
Jul 16, 2020
Posts
79
Reaction score
34
Location
Spartanburg
There are only two items connecting to the u-joint; the driveshaft and the rear end. The rear end has lube in it and the driveshaft does not. Not too hard to guess. It looks like the pinion seal may be bad.
yeah when you put it like that it makes more sense, also the ribbed looking cover over the rear diff case that the u joint is connecting into can spin freely with my fingers spinning it. Is that normal or showing that its loose?
 

92LongBed

Registered User
Joined
Jul 16, 2020
Posts
79
Reaction score
34
Location
Spartanburg
it's possible the diff oil is just dripping from the ujoint depending on terrain, but there's grease/lube in the u-joint too that could be 'dripping'. when doing the pinion seal i also relplaced that u joint as well since it was worn (and maube a cause of the pinion leak? who knows).

happy to help with any q's or send relevant youtube vids
i appreciate it. i'd love to get any YT vids you used but I 'm not sure I have the proper tools for this job so not sure if i should try this one. i'm pretty savvy with my truck but need a torque wrench and potentially a bearing puller right?
 

rreegg

Full Access Member
Joined
Feb 10, 2022
Posts
237
Reaction score
137
Location
Puget Sound
this guy does it quick and dirty but it's a good basic way to see it getting done in the field, there are other ways that are more "by the book" (new crush sleeve or crush sleeve eliminator spacers but not mandatory) - to only do the pinion seal you only need basic tools. it looks like your ujoint strap bolts are torx t40 head instead of 12 point 5/16.

xc_hide_links_from_guests_guests_error_hide_media
 

92LongBed

Registered User
Joined
Jul 16, 2020
Posts
79
Reaction score
34
Location
Spartanburg
this guy does it quick and dirty but it's a good basic way to see it getting done in the field, there are other ways that are more "by the book" (new crush sleeve or crush sleeve eliminator spacers but not mandatory) - to only do the pinion seal you only need basic tools. it looks like your ujoint strap bolts are torx t40 head instead of 12 point 5/16.

xc_hide_links_from_guests_guests_error_hide_media
you're a legend thank you for sharing, havent seen this vid yet
 

hacked89

Full Access Member
Joined
May 30, 2018
Posts
1,737
Reaction score
2,327
Location
Bucks County PA
I’d recommend it’s time to start buying tools, cheap are fine, and start wrenching. You can do it. It’s all easy. A good impact, some harbor freight esque torque wrenches and you’re on your way. In 15 minutes you can have the driveshaft off the yoke and see clearly your pinion leak.

You started thinking about this April 17th, we could have had you fixed before May.
 

IDIBRONCO

IDIBRONCO
Joined
Feb 5, 2010
Posts
12,233
Reaction score
10,925
Location
edmond, ks
also the ribbed looking cover over the rear diff case that the u joint is connecting into can spin freely with my fingers spinning it. Is that normal or showing that its loose?
That's either the seal of part of the seal that's no longer attached. Either way, I'm pretty sure that it's not supposed to spin.
 

Latest posts

Forum statistics

Threads
91,217
Posts
1,128,471
Members
24,043
Latest member
tottripp

Members online

Top