2 ?'s about my diff

[dalefanatic38]

1. do i need any special tools or need to know anything special about replacing my pinion seal on the rear diff.

2. i wasnt paying attention when i bought my diff oil and got all 75w140 royal purple. is this alright to use in both front and rear diffs.

 

[skoal_mint]

i did it on my frint diff awhile ago, its not that hard and only took me about 30 minutes.

take off the drive shaft, mark the pinion bolt and the yoke befor taking off the bolt so when you tighten it back up and still has the same toruqe..

but your slef a seal puller, it make the job easy..Thats about all

Getting the yoke off it the hardest part, but just keep hitting it with a hammer and she will come off slowly

 

[dalefanatic38]

cool that sounds easy enough. i hope the diff fluid i got wont hurt anything.

 

[KLW]

The problem is overtightening the nut and crushing the sleeve inside that sets the brg preload. The manual gives a torque reading that one should be able to achieve without drushing the sleeve and making the brgs too tight. You could mark the position of the nut in relation to the yoke but you'll also have to put the yoke on exactly the right spline which might be hard to tell unless you mark it very well. You'll need some way of holding the yoke if using a torque wrench. One could get by with an impact wrench if one is familiar with the torque characteristics but one would have to be extremely careful. Many a brg has been ruined by overtighteing. In theory, the nut should be tight enough to not come loose and not too tight to crush the sleeve. Make sure you can easily by hand work the yoke back and forth. If it's tighter then that you will have to pull the seal, outer brg and replace the crush sleeve and then you'll need a very good extra long breakover bar and tool to hold yoke to crush the new sleeve.

As far as oil, make sure it doesn't have a special tag on rearend saying it needs synthetic oil or check owner's manual.

 

[dalefanatic38]

it does say to use synthetic oil in my haynes book.

 

[dalefanatic38]

o do you know that torque setting. i cant find it in my book.

 

[KLW]

I would think a torque of around 135 lbs would do it but I won't have access to a manual until Monday at work.

 

[dalefanatic38]

thats cool if that is close. im doing it on saturday.

 

[Doug]

135 ft lbs!? Nooo. Since you already have the crush sleave installed and crushed you do not torque it that high. Once you've replaced the seal tighten it up until you start to feel some resistance when you spin the pinion. Put an inch pound torque wrench on the pinion nut and tighten it until it takes between 25-35 inch pounds to turn the pinion. Any tighter or looser will damage the pinion bearings. To pull the old seal you can drill 2 screws into the pinion seal and then use them to pull the seal out. Your front diff takes 85w-90, and the rear will take 75-140 if it has 4.10 or higher gears or limited slip. I've done the pinion seal on my front diff and it's not to bad to do.

When you're torqueing the pinion take your time. The bearing preload ramps up pretty fast and what you think isn't much tighter will make a big difference in the bearing preload. It's definitely easier to do with an impact wrench, I would imagine it would be a pain to do by hand as it's pretty hard to keep the pinion in place. If you put to much preload on the bearings you'll have crushed the crush sleeve to much and you'll have to replace the crush sleave. It's not a real big deal and they're cheap but it's just more work you have to do.

 

[KLW]

Doug, do you have manual info to back up your claim of 135 being way too high? There is a torque that one should be able to obtain without further crushing the sleeve. Crushing the sleeve sometimes takes 250ft lbs. The last one I did took an extra long breakover bar to obtain.

The torque spec I found looking through the net is 140 ft lbs minimum to crush the sleeve. My feeling is that one should be able to torque it up to 140 without further increasing preload. If preload increases (you can go by feel of the torque required to turn pinion) you need a new crush sleeve. I believe the Ford manual will actually say that this would be the spec I was talking about. If it can't maintain this torque there is a good chance of having too much bearing preload and or the yoke will eventually work loose.

 

[daffy]

This is all the ford shop manual says:

Installation

Verify that the splines on the pinion stem are free of burrs. If burrs are evident, remove them with a fine crocus cloth. Work in a rotating motion to wipe the pinion clean.
Clean the pinion seal bore.
Install a new collapsible spacer.
Install the original differential pinion bearing and the front axle drive pinion shaft oil slinger.

Lubricate the pinion seal.
Use Motorcraft SAE 80W90 Thermally Stable 4x4 Axle Lubricant meeting Ford specification WSP-M2C197-A.
Using the special tool, install the pinion seal.

Lubricate the pinion flange splines.
Use Motorcraft SAE 80W90 Thermally Stable 4x4 Axle Lubricant meeting Ford specification WSP-M2C197-A.
CAUTION: Never use a metal hammer on the pinion flange or install the flange with power tools. If necessary, use a plastic hammer to tap on a tight fitting flange.

Align the index marks and install the pinion flange.

Install the new nut hand-tight.

CAUTION: Do not loosen the nut to reduce preload. Install a new collapsible spacer and nut if preload reduction is necessary.

Use the special tool to hold the pinion flange while tightening the nut to set the preload.
Tighten the nut, rotating the pinion occasionally to ensure the differential pinion bearings are seating correctly. Take frequent differential pinion bearing preload readings by rotating the pinion with a Nm (inch-pound) torque wrench. The final reading must be 0.56 Nm (5 lb-in) more than the initial reading taken during removal.

Align the index marks and position the front driveshaft.

Install the universal joint spider retainers and bolts.

Check the fluid level and, if necessary, fill the axle to specification.
Use Motorcraft SAE 80W90 Thermally Stable 4x4 Axle Lubricant meeting Ford specification WSP-M2C197-A.

 

[KLW]

Look in the torque spec table and see if it's there. According to what you quoted one would have to replace the crush sleeve every time one does the seal. If replacing the crush sleeve I found out that some grease on the nut prevents galling of the nut and yoke which would make crushing the sleeve very difficult.