Rear diff Service questions

[danno2944]

Truck has been running great thanks to the forum, thanks everyone!

I am planning on changing the rear bearings and changing gear oil in diff.

I have the sohc with 4:10 limited slip. Needs 75w140 synthetic with friction modifier.

Just doing a bit of reading about the rear differential cross pin bolt that is common to breaking during removal.

Is their anything I can do to prevent this bolt from breaking, Pre heating etc..? Any other tips on rear diff service?

Also wondering about opinions on the which gear oil to use? The motocraft fluid is $40 a quart here, I have heard about royal purple and amsoil but people are still adding the friction modifier?

Off topic.... I also have a front end squeak that has developed on DS front. Does any on have a method on tracking down the squeak? I do believe it's the lower Balljoint. No play or rattling or pulling during driving, just a squeak over bumps and turning over bumps?

 

[donalds]

I used m1 75-140
As far as the cross pin you could try heating it first
I'd have the tool ready
Differential Pinion Shaft Lock Bolt Extractor Deluxe Kit

 

[donalds]

I used m1 75-140
As far as the cross pin you could try heating it first
I'd have the tool ready
Differential Pinion Shaft Lock Bolt Extractor Deluxe Kit

And I forgot to say use friction modifier if you have a limited slip

 

[imp]

@danno2944
By rear bearings, you mean wheel bearings, not differential carrier bearings, right? Either require removal of the lock bolt, since axles must be removed. imp

 

[donalds]

Off topic.... I also have a front end squeak that has developed on DS front. Does any on have a method on tracking down the squeak? I do believe it's the lower Balljoint. No play or rattling or pulling during driving, just a squeak over bumps and turning over bumps?

As for the squeak my method is to spray the ball joint then drive it see if it goes away
Do Only One component at a time

Lower ball joint
Test drive
Tie rod end
Test drive
Upper ball joint
Test drive
Etc...

 

[danno2944]

@danno2944
By rear bearings, you mean wheel bearings, not differential carrier bearings, right? Either require removal of the lock bolt, since axles must be removed. imp

The wheel bearings.

The Boots are good on the ball joints and tie rod ends, so I don't want to puncture or risk tearing it by stretching by trying to lube to see if it stops..the struts are new, I thought that was the squeak.
Since the struts were so crappy I assume that would wear out the ball joints quickly, sounds metal grindish, It really creaks good for you going Over bumps and Turning and is getti
The Endlink rubber is terrible I have new ones to install. Just not sure they are the cause of the sound?

Donald's I appreciate the link. Hopefully I won't need it...did yours break?

Would PB blaster being sprayed in diff and or heat to treat this bolt be ok forr the diff?

 

[donalds]

Yes I have had one break
If it is broke it happened already they break in the housing by themselves not anything you did

I don't think heating It will hurt it
heat it just to release the lock tight
Pb blaster won't do anything the whole thing is already coverd in oil anyway

When I had a creek in my front end it was a lower ball joint sounded like a old door creaking

 

[danno2944]

And I forgot to say use friction modifier if you have a limited slip

Thanks, it is a Limited slip which is why I am asking.

It Seems counter intuitive using two different products though. I will let Ford bend me over for this one.

 

[donalds]

No no no just get m1 and ford friction modifier

The modifier is cheep to don't wast your money
If you want to buy the best oil for the same money at ford get amsoil

 

[danno2944]

Ok, I have always used Mobil one products and I do trust them. So your saying the Mobil is the same price as the motocraft though? Royal Purple the most expensive I imagine..

 

[donalds]

https://www.amazon.com/Ford-XL-3-Fr...4&sr=8-20&keywords=75w-140+synthetic+gear+oil

Advance Auto Parts - Down for Maintenance

 

[donalds]

The m1 is I would think cheaper than motor craft
And it's synthetic all the oil and modifier was around $60 when I did mine

I think amsoil is the most $

 

[swshawaii]

Interesting test from a reportedly "independent" lab. Test is for 75W-90, not 75W-140 which is now recommended for ALL 8.8 diffys. Amsoil has an intermediate 75W-110 that is supposedly the same as 75W-140 using the old test procedure. I'm using one Amsoil product in my ST, and it's Severe Gear 75W-90 lube. Very quiet and would use it again in a heartbeat. Still stinks though. LOL

http://www.goodsenseoil.com/G2457-GearOilWhitePaper.pdf

 

[roscoe 0202]

i'm an amsoil guy but I think any good quality synthetic would be just fine I use 75-90 amsoil because it is severe duty oil
roscoe

 

[Mbrooks420]

99 won’t have any struts. Will be generic shocks on all 4 corners.

Some full synthetic gear lube has the friction modifier already in it.

As for the squeaking you don’t need to stretch the boots. Just spray the exposed area a bit, and it will seep in, especially if they are bad. I’d use a lubricant and not WD-40.

 

[danno2944]

99 won’t have any struts. Will be generic shocks on all 4 corners.

Some full synthetic gear lube has the friction modifier already in it.

As for the squeaking you don’t need to stretch the boots. Just spray the exposed area a bit, and it will seep in, especially if they are bad. I’d use a lubricant and not WD-40.

My bad, the shocks were replaced not struts..

I guess the more important thing may be to note is that the winter can be quite severe/cold here which may change the diff fluid choice.

I am worried about the modifiers already in the gear oils which is one of the reasons I was saying I would stick with the motocraft. It should clearly state on the label though, correct?

What's your idea of lube not wd40? Mine is fluid film, lithium or silicone, neither of which will "seep in" imo.

 

[danno2944]

Interesting test from a reportedly "independent" lab. Test is for 75W-90, not 75W-140 which is now recommended for ALL 8.8 diffys. Amsoil has an intermediate 75W-110 that is supposedly the same as 75W-140 using the old test procedure. I'm using one Amsoil product in my ST, and it's Severe Gear 75W-90 lube. Very quiet and would use it again in a heartbeat. Still stinks though. LOL

http://www.goodsenseoil.com/G2457-GearOilWhitePaper.pdf

i'm an amsoil guy but I think any good quality synthetic would be just fine I use 75-90 amsoil because it is severe duty oil
roscoe

If you have LSD, Did you use the friction modifier? Wondering if this severe duty oil would suit me better for the cold weather?

 

[Mbrooks420]

WD-40 is a solvent, which is why it’s good at freeing stuck things. I’d use Kroil.

I think either weight of gear oil would be fine. It gets fairly cold here in the winter and the stock oil weights have always worked for me.

 

[donalds]

Jeeez wd40 was suggested as a temp use to find the problem joint s
Everyone wants to argue over it how ever I agree it used to be used to free up rusty nuts and bolts mostly
Lubricants, Degreasers & Rust Removers -- WD-40 Uses & Tips
Now in 2018 it's a light oil in it read the bottle
It will help find the bad joint no amount of any lube will fix a bad joint replace it

As far as friction modifier use it it's like $5 do you like doing all this work again don't cheep out on your rear end been there done that

This is all in my opinion not trying to ruffle feathers

 

[Mbrooks420]

Jeeez wd40 was suggested as a temp use to find the problem joint s
Everyone wants to argue over it how ever I agree it used to be used to free up rusty nuts and bolts mostly
Lubricants, Degreasers & Rust Removers -- WD-40 Uses & Tips
Now in 2018 it's a light oil in it read the bottle
It will help find the bad joint no amount of any lube will fix a bad joint replace it

As far as friction modifier use it it's like $5 do you like doing all this work again don't cheep out on your rear end been there done that

This is all in my opinion not trying to ruffle feathers

You didn’t actually suggest using WD40 as the spray.... lol. If the joint is bad, sure it won’t hurt, but I wouldn’t want it getting into a good one.