Upgraded Differential on 2nd Gen?

[Vancouver Bob]

Hey Guys....and gals. My '03 Expy has open differentials and I'm very interested in upgrading to either a Eaton Truetrac limited slip or a locker. I've done a bit of research and I'm discovering that not many or anyone offers something for the 9.75 IRS rear end. Evidently the rear drive axles are the type that have a circular spring clip that sits at the end of the shaft which then locks the shaft into place when the clip reaches a slot inside the side gear. Unlike the shafts that have a ring clip that gets inserted at the end of the shaft once the shaft is installed into the differential. ARB supposedly issued a news release saying they offered a locker for the 9.75" 34 spline but come to find out that it's not compatible with the IRS. I talked to an ARB tech rep and he said the side gears would need to get machined for it to work.

For the front, I think it's an 8.8" same as the F150 but not positive. If it is, there'd be more offerings.

Anyone do any upgrades?

Thanks!
Bob

 

[Hamfisted]

Probably quickest and "easiest" way to do it is just go to a salvage yard and find an Expy or Navigator with a "H6" code on the door jamb sticker ( 3.73 Limited Slip ), and pull and swap with that complete axle. Unless you're going rock crawling that should be good enough. The limited slip axles were actually more common than non-limited slip .



-Mike

 

[Vancouver Bob]

Hi Mike... that would be the easiest approach. What I hear though is that a clutch type limited slip becomes an open diff after 20K miles or so as the clutch packs wear. They are replaceable though. So an option would be to simply rebuild during the install and be good to go for a few years which may very well be good enough. Thanks for the suggestion!!

 

[ExplorerTom]

I wouldn't do the clutch limited slip. If it is worn out and you get into a situation where you actually need it- you'll want a diff that works.

 

[Vancouver Bob]

I wouldn't do the clutch limited slip. If it is worn out and you get into a situation where you actually need it- you'll want a diff that works.

That's what I was thinking too. Probably worth the extra money to put towards a swap to something better than a standard LSD. I'm also planning on changing gears while I'm at it (well... I mean while the shop is at it). Figure everything is all torn apart so cost to have them swap out the differential would be essentially free. I'm just not finding anything for the 2003 (and on) because of the axle setup with the independent rear suspension.

 

[plumcolr]

Dunno about the 20k wearout. Mine has 180k on it and the torque wrench test still shows around 100 ft-lb. I believe spec calls for 50-200 ft-lb.

 

[Vancouver Bob]

Dunno about the 20k wearout. Mine has 180k on it and the torque wrench test still shows around 100 ft-lb. I believe spec calls for 50-200 ft-lb.

Good to know, thanks!

I can't remember where I read that.... but I'm sure all LSD's aren't created equal. I'm thinking putting in a new LSD differential may be the ticket since I can't find anything else that will work without doing some modification.

 

[plumcolr]

I suspect that people that use them hard will get significantly less wear than normal drivers.

I'm pretty easy on cars, except cosmetically ;-) last 2 both went over 300k from new.

 

[Vancouver Bob]

I suspect that people that use them hard will get significantly less wear than normal drivers.

I'm pretty easy on cars, except cosmetically ;-) last 2 both went over 300k from new.

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!

 

[theoldwizard1]

Personally, I would install an E-Locker.

 

[98eb5.4]

Hey Guys....and gals. My '03 Expy has open differentials

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

 

[JExpedition07]

https://www.carid.com/ford-performa...204-f318c.html?singleid=56773784&url=84934582

Brand new ford ones. (LSD).

 

[98eb5.4]

https://www.carid.com/ford-performa...204-f318c.html?singleid=56773784&url=84934582

Brand new ford ones. (LSD).

that's for 8.8

 

[Vancouver Bob]

Personally, I would install an E-Locker.

Hi Wizard... would you happen to know who makes one for the Ford 9.75" rear end with IRS? 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. In talking with ARB, they said I'd have to have the side gears modified... probably voids all warranties .

 

[Vancouver Bob]

https://www.carid.com/ford-performa...204-f318c.html?singleid=56773784&url=84934582

Brand new ford ones. (LSD).

Thanks, JE07. But when I look at that I think it's for the front differential...


The rear is a 9.75 34 spline. But I'm sure I can get a new replacement LSD since they did offer them for my model year.

 

[Vancouver Bob]

that's for 8.8

Ha!! You beat me to it!

 

[98eb5.4]

Thanks, JE07. But when I look at that I think it's for the front differential...

View attachment 22224
The rear is a 9.75 34 spline. But I'm sure I can get a new replacement LSD since they did offer them for my model year.

but u said?

"My '03 Expy has open differentials"

what gear ratio?

 

[98eb5.4]

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

 

[98eb5.4]

Probably quickest and "easiest" way to do it is just go to a salvage yard and find an Expy or Navigator with a "H6" code on the door jamb sticker ( 3.73 Limited Slip ), and pull and swap with that complete axle. Unless you're going rock crawling that should be good enough. The limited slip axles were actually more common than non-limited slip .

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/

 

[JExpedition07]

Thanks, JE07. But when I look at that I think it's for the front differential...

View attachment 22224
The rear is a 9.75 34 spline. But I'm sure I can get a new replacement LSD since they did offer them for my model year.

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