Upgraded Differential on 2nd Gen?

[JExpedition07]

how'd you find that out? what gear ratio?

Rear Axle Code on your door jamb sticker. You can look up the letter bank. C is open diff L is LSD after your gear ratio. Heres the breakdown on decoding it.

 

[98eb5.4]

Yes that's absolutely true too.

Was reading a few things last night that said Expys with AdvanceTrac all have open diffs. Anyone know if that's true? I thought AdvanceTrac came standard. I wouldn't want to muck with the system by adding something it isn't expecting and cause problems.

Funny about the cosmetics comment!

got a link? not sure when advancetrak was prob first an option, then across the board on expys

-edit: had a quick look, started as an option on 2nd gen

https://www.ford-trucks.com/forums/...dvance-trac-vs-limited-slip-differential.html

http://www.expeditionforum.com/threads/advancetrac-vs-limited-slip.28870/

 

[theoldwizard1]

Hi Wizard... would you happen to know who makes one for the Ford 9.75" rear end with IRS?

First, to show you what I DON't know, I thought it was an 8.8 ! Obviously I am no "wizard" on rear axles.

Hi I can find lockers for the 2002 or earlier with the solid axles but nothing for the 2003 and on. I'm told it's because of how the axle shafts are held into the side gears (ring clip vs c clip). The ring clips require side gears with a retention feature. Evidently not something most aftermarket differentials can accommodate.

That just does not "smell" right. I can not believe Ford would have 2 different methods of retaining the axle, one for solid axles and one for IRS. I could be wrong.

Shopping around, some of the places selling 9.75 LSD says they fit F150 (solid axle) AND Expedition (half shafts).

 

[Texpedition45]

Do a quick search.

I can't for the life of me recall which member did it, but there's one on here with a... 2011? and an air locker. I think there's a parts number mentioned as well.

 

[98eb5.4]

https://www.ford-trucks.com/forums/992942-advancetrac-vs-advancetrac-rsc.html

 

[plumcolr]

That pretty well explains what I thought: AdvanceTrac works by selectively applying braking to the slipping wheel; not effective for drag racing or smoking the tires, and addition of a LSD will really not work well. In fact might make for unpredictable behavior (read might be dangerous under severe conditions), just like using 4wd in an inch or two of wet snow.

 

[ExplorerTom]

Hi Wizard... would you happen to know who makes one for the Ford 9.75" rear end with IRS?

The 9.75 was used in the IRS 2nd gens?

 

[98eb5.4]

https://www.ringpinion.com/b2c/DiffDetails.aspx?DiffID=319&SearchMode=Diff&TypeID=4

"Compatible with Models:
Expedition: 2003 - 2013 (Rear)
Navigator: 2003 - 2014 (Rear"

https://www.yukongear.com/partcats.aspx?SearchMode=Diff&TypeID=4&Type=Ford&DiffID=319&DiffName=Ford+9.75"+IRS

http://www.expeditionforum.com/threads/aftermarket-limited-slip-for-9-75-diff.2052/#post-9293

http://www.expeditionforum.com/threads/aftermarket-limited-slip-for-9-75-diff.2052/

 

[Vancouver Bob]

but u said?

"My '03 Expy has open differentials"

what gear ratio?

That I did... and I do . But I know they offered LSD's so seems it would be easy to find one. But I'd really rather put the money towards a selectable locker.

 

[Vancouver Bob]

Oh I have 3.73 gears with the 16 axle code which I think is an open diff.

 

[Vancouver Bob]

https://www.ringpinion.com/b2c/DiffDetails.aspx?DiffID=319&SearchMode=Diff&TypeID=4

"Compatible with Models:
Expedition: 2003 - 2013 (Rear)
Navigator: 2003 - 2014 (Rear"

https://www.yukongear.com/partcats.aspx?SearchMode=Diff&TypeID=4&Type=Ford&DiffID=319&DiffName=Ford+9.75"+IRS

http://www.expeditionforum.com/threads/aftermarket-limited-slip-for-9-75-diff.2052/#post-9293

http://www.expeditionforum.com/threads/aftermarket-limited-slip-for-9-75-diff.2052/

Thanks!! I've stumbled across the Yukon in my searching and is definitely a possibility. Had hoped to be able to get one of the selectables to work and not ready to throw in the towel just yet .

 

[Vancouver Bob]

Oops sorry. Many options for LSD here’s a rear https://www.carid.com/2006-ford-exp...gear-limited-slip-differential-503435323.html

Thanks, JE070! There are definitely some good LSD options out there.

Anyone know if a limited slip is compatible with Advanctrac? I have read that the Expeditions with Advanctrac all came with open differentials, perhaps to keep the systems from fighting with each other?

 

[Vancouver Bob]

pretty sure, all 3.73s were lsd,

& yes, if your original diff was lsd, you can just replace the clutch pack,

can't just do that tho with an original open diff

I have 3.73 gears but was disappointed when I discovered I have an axle code of 16..

Code Gear Ratio (L - limited slip, C - open differential)
15 3.31C
16 3.73C
17 (1997) 3.73C
17 (1998) 3.55C
17 (1999-2002) 3.31C
19 3.55C
H5 3.31L
H6 3.73L
H7 3.31L
H9 3.55L .

 

[Vancouver Bob]

op hasn't said what gear ratio they have, if not 3.73, they have to match, front & back

op needs to know what starting with? before what next

expys had 3.73 - .55 -.31 sized 8.8 or 9.75

http://www.fourwheeler.com/how-to/transmission-drivetrain/129-0802-ford-f150-975-axle-build/

Thanks! The 9.75 TrueTrac they show is designed for that C-clip retained solid axle used on the F-150's. Same with the ARB. They say I'd have to have the side gears modified to get it to work.

 

[Vancouver Bob]

Rear Axle Code on your door jamb sticker. You can look up the letter bank. C is open diff L is LSD after your gear ratio. Heres the breakdown on decoding it.
View attachment 22226

Thanks!! I didn't see this until just now. I think I cut and pasted from the same site .

 

[Vancouver Bob]

Thanks, JE070! There are definitely some good LSD options out there.

Anyone know if a limited slip is compatible with Advanctrac? I have read that the Expeditions with Advanctrac all came with open differentials, perhaps to keep the systems from fighting with each other?

Just found this...

According to Ford, a 2004 4X4 with advance trac cannot use a limited slip differential. I deal with lots of snow (Canadian North) and have felt that when stuck in deep snow a standard axle would not provide more than 1 drive wheel in the rear and 1 in front. According to the owners manual when things get tough they recommend turning the advance trac off for better traction in deep snow or mud. For this reason I have factory ordered a 2004 "without" advance trac and "with" limited slip rear axle.

Can personally attest to the comment about better traction in snow/sand with advance-trac off.

 

[Vancouver Bob]

So if I believe everything I've read... my only option would be a selectable locker since I can't run an LSD with the Advance-Trac.

First, to show you what I DON't know, I thought it was an 8.8 ! Obviously I am no "wizard" on rear axles.


That just does not "smell" right. I can not believe Ford would have 2 different methods of retaining the axle, one for solid axles and one for IRS. I could be wrong.

Shopping around, some of the places selling 9.75 LSD says they fit F150 (solid axle) AND Expedition (half shafts).

Ha ha... funny about not being a wizard on rear axles!

That ARB RD-150 was first touted to fit up to the 2003 Expeditions but as I looked deeper some places said it did and others said it didn't. Called ARB and that's when the guy told me about the differences in how the axles were retained. Without the locking feature in the side gears the half shafts would potentially slide out over time.

 

[Vancouver Bob]

Do a quick search.

I can't for the life of me recall which member did it, but there's one on here with a... 2011? and an air locker. I think there's a parts number mentioned as well.

I'm guessing it was the RD-150 because it's designed for the 9.75 34 spline axle. I'll search around some more, thanks!

 

[blue oval guy]

I don't know but my 05' in 4 low is an unstoppable beast in the snow even without a rear locker.

 

[Vancouver Bob]

I don't know but my 05' in 4 low is an unstoppable beast in the snow even without a rear locker.

I hear you... in general I totally agree! Just a few times where I've had opposite corners spinning and I was completely stuck. Once on my driveway! The neighbors helped push me out. And as they were pushing they asked, "Doesn't this have 4 wheel drive?" . I've had similar challenges in the sand. Even having an LSD would have been nice.