Getting a progressivly worsening leak from my rear diff and have determined that its a pinion seal, my question is.... is this a repair I can do myself? Im not a complete idiot and have an awesome set of tools, so is there anything critical I should know if I attempt it?

 

Welcome !

quote- "is there anything critical I should know if I attempt it?"

If we're talking F-150, then yes, you should know that if you remove the pinion nut, that resetting the pinion preload will be guesswork unless the carrier is removed. You should also replace the crush sleeve. To pop off the pinion nut and exchange seals is not a proper way to repair this and typically mechanics don't guarantee this method.

This site includes the proper repair:
www.ring-pinion.com/tech/yukoninst.pdf

After reading the subsequent posts, I edited my answer to include that pinion nuts as well as crush sleeves are one time use items IMO.

 

hey, always remember to try the cheap remedy first. pour a half bottle of stop leak in first and see if that fixes your leak

 

Stop leak is worthless. you'll need loctite(blue) for the pinion nut. I highly recomend you retorque the pinion nut when you put it back in. Hopefully it's just a seal and not the sign of the pinion bearing going bad.
Alan

 

You can replace the pinion seal yourself, here is how you do it.

1. Remove or drop the driveshaft. Mark it and the pinion flange so they can go back in the same position.

2. Remove the pinion nut. DO NOT use an impact wrench!!! This will put a shock load on the pinion and ring gears, causing a tooth to chip or break.

3. Remove the pinion flange, then drive out the old seal. This can take some time. Be patient and work the seal out, be careful not to nick or damage the bore the seal presses into. This will make installing the new seal difficult.

4. Install the new seal, you can use a large socket or piece of pipe. Your install tool should rest on the metal ring around the seal. Position it square in the bore and drive the seal into position.

5. Reinstall the pinion flange and torque the nut to spec. Usually anywhere between 70 and 100 ft.lbs. Make sure you rotate the pinion while you torque it to get an accurate reading and get proper preload. This is why I said to mark things.

6. Reinstall the driveshaft lining up your marks, and you are ready to go! One more thing, when you install the pinion flange put some gear lube on it and work it back and forth to make sure you don't pinch the seal and damage it. Also if the sealing surface on the flange looks grooved or damaged in any way, replace it or you will be doing this job again in a few hundred miles.

Good luck.

BTW don't forget to refill the diff.

 

Well I guess I'm gonna have to buy a inch pound torque wrench after reading this below that is pasted.

? - when I go to remove the carrier (I know to keep the caps in the same position etc.) (Never worked on a Ford's rear/carrier) will it come out when I remove the caps or will the carrier have to be pryed open a little?

Referance post to pinion seal:
( https://www.f150online.com/forums/ot...ear-end-5.html )



Complements of - Jackal


Copy / Paste from Factory Service DVD for 2001 F-150 8.8: (I'm sure it's the same for 9.75)

-------------------------------------------------------------------------------------

Drive Pinion Flange

Special Tool(s) 2-Jaw Puller
205-D072 (D97L-4221-A) or equivalent
Holding Fixture, Drive Pinion Flange
205-126 (T78P-4851-A)
Installer, Drive Pinion Flange
205-002 (TOOL-4858-E) or equivalent

Material Item Specification
SAE 75W-140 High Performance Rear Axle Lubricant
F1TZ-19580-B or equivalent WSL-M2C192-A

Removal:
All vehicles

Raise and support the vehicle. For additional information, refer to Section 100-02 .
NOTE: The rear wheels and brake drums/calipers must be removed to prevent brake drag during drive pinion bearing preload adjustment.

Remove the wheel and tire assembly. For additional information, refer to Section 204-04 .

Vehicles with drum brakes:
Remove the rear brake drums. For additional information, refer to Section 206-02 .

Vehicles with disc brakes:
Remove the rear disc brake caliper. For additional information, refer to Section 206-04 .
Wire the rear disc brake caliper aside.
Remove the rear brake disc.

Mark the driveshaft flange and pinion flange for correct alignment during installation.

Remove the four driveshaft bolts.

CAUTION: The driveshaft centering socket yoke fits tightly on the rear axle pinion flange pilot. Never hammer on the driveshaft or any of its components to disconnect the yoke from the flange. Pry only in the area shown with a suitable tool to disconnect the yoke from the flange.

Using a suitable tool as shown, disconnect the driveshaft centering socket yoke from the rear axle pinion flange.

Position the driveshaft out of the way.

Install an inch-pound torque wrench on the pinion nut and record the torque required to maintain rotation of the pinion through several revolutions.

CAUTION: After removal of the pinion nut, discard it. A new nut must be used for installation.

Using the special tool, hold the pinion flange and remove the pinion nut.

Mark the pinion flange in relation to the drive pinion stem to make sure of correct alignment during installation.

Using the special tool, remove the pinion flange.

Installation:
All vehicles

Lubricate the pinion flange splines with rear axle lubricant.
NOTE: Disregard the scribe marks if a new pinion flange is being installed.

Align the pinion flange with the drive pinion shaft.

With the drive pinion in place in the rear axle housing, install the pinion flange using the special tool.

Position the new pinion nut.

CAUTION: Under no circumstances is the pinion nut to be backed off to reduce preload. If reduced preload is required, a new collapsible spacer and pinion nut must be installed.

CAUTION: Remove the special tool while taking preload readings with the Nm (inch-pound) torque wrench.

Using the special tool hold the pinion flange, tighten the pinion nut.
Rotate the pinion occasionally to make sure the cone and roller bearings are seating correctly.

Install a Nm (inch-pound) torque wrench on the pinion nut.
Rotating the pinion through several revolutions, take frequent cone and roller bearing torque preload readings until the original recorded preload reading is obtained.
If the original recorded preload is lower than specifications, tighten to the appropriate specifications for used bearings. If the preload is higher than specification, tighten the nut to the original reading as recorded. For additional information, refer to Torque Specifications in this section.

Position the rear driveshaft and align the marks on the pinion flange.

CAUTION: The driveshaft centering socket yoke fits tightly on the rear axle pinion flange pilot. To make sure that the yoke seats squarely on the flange, tighten the bolts evenly in a cross pattern as shown.

Install the bolts.

Vehicles with drum brakes:
Install the rear brake drums. For additional information, refer to Section 206-02 .
Vehicles with disc brakes


Install the rear brake disc:
Install the rear disc brake caliper. For additional information, refer to Section 206-04 .

 

Why do you want to remove the carrier?
You do not have to remove the carrier to replace the Pinion Seal.
But you will have to make some sort of a tool to hold the flange while tightening the Pinion Nut. I used 1/4" plate and cut it out with a torch then drilled the holes for the flange bolts.
Just tighten it a little and recheck and then tighten some more and then recheck.
I got me inch pound torque wrench from O'Reilly Auto Parts and it was a KD brand and cost about $50.00.
Make sure you remove any thing that will drag the axles (drums, pads, and so on).
Torque the nut to about 14 inch pounds for used bearings.
This will take about 250 FT pounds on the nut to get you to 14 inch pounds.
You may have to put a pipe on a 3/4" drive ratchet to tighten the nut.

 

That is what I'm saying, wow, & also a crush sleeve.
Technology !

 

Above all else remove the vent hose and the axle vent and be sure the vent is not rusted shut or the hose filled with dirt and mud, this is one of the biggest causes of seal failure. Many times just cleaning the vent will fix the problem.

 

Never thought of that & I 4 wheel all the time. I did notice at the top of the vent there is oil & the area is black w/it so I guess it's working. (notice the left side of the pic)



I looked @ it before and there seem to be a channel where it's dead ended. Can I just detach the tube from the axle & blow compressed air through it OR ...

 

Ok, since my torque wrench only went to 150lbs & my friend is not home w/ his 250+ wrench he uses on his race cars, my son & I decided to just go ahead & replace the fluid w/ the cheap stuff until we can get to my Buddy's to get his T-wrench. The truck only goes about 50 miles a week & w/250K it is still strong . We just wanted to make sure it was right so we opted to just change out the factory fluid & keep a eye on the seal (I did add dyno oil to it & it stopped leaking a few months ago. I didn't know it took synthetic, I'm old school).

Here are some pics the rear, looks good. The rest of the pics can be seen here: ( Street2Mud.com under my '97 Ford F150 album I just started. To view my whole album please go to Street2Mud.com

Note: click on the picture to view a bigger size in my albums.

Sweet smell right here folks


Yes my son likes green. Finished.


I just want to thank everyone for their comments and help on this thread & the other one linked to it. As you can see from my albums i am quite capable but I have never ventured into Ford rears to much, especially newer vehicles. Everything else is 24 yrs. or older.

Thanks again & I hope I didn't bother anyone w/ stupid questions. Nice place & I would like to hang around for a while.

Jim

P.S. Sorry, I guess I should have put this on the other post I linked to here since we are just dealing w/the fluid at this point. Mods, move it if need be.

-> https://www.f150online.com/forums/ot...ear-end-5.html

 

By the way you do not use a 250+ torque wrench.
You use a 3/4" ratchet or something to turn the socket.
You check the torque with a 0-50 inch pound torque wrench.
Set the torque at 14 inch pounds.

 

Sorry misunderstood you. @ any rate I still have to get a inch T-wrench. Stores didn't have one today when I checked.

 

The one I got from O'Relly Auto Parts and they had to order it was a 0-60 inch pound torque wrench. It was KD #2955 1/4" drive.

 

Thank you, trying to find a dial T-wrench but if I can't find one @ reasonable price I will order this one.