diff thingys?

[Anonymous]

looked under the car on the weekend to see how hard the diff change would be.... there is 2 bars that run from either rear wheel and meet in the centre behind the diff (behind being at the rear of the car) what are these???? they have printed on them.. "do not use for jacking or towing" or something to that extent.... are they easily removed so i can take the diff centre out??

also, im sure ive asked before, but will the 3.23 ratio diff centre bolt straight back into the original 2.77 space... will the axels be different?? i really wanna see what kinda difference ill get

cheers
-matt-

 

[xctasy]

Important: What follows is a primary safety matter. Although simple, any diff swap requires quite a lot of good workshop practice. Get some additional advice from a Gregories, Ellery, or Ford workshop manual, and pick the brains of some one who has done what you're asking.

These little numbers are the Watts Linkage. They control lateral location of the axle and stop the axle moving from left to right during cornering.

The two bolts on the chassis and one at the toggle at the diff (the Watts Linkage) are easily removed. Since the Watts link is connected to the diff plate, its fairly easy to take the plate off. All the oil then pi**es out, so you need a 500 mm square by 25 mm deap tray or a kitty litter box for all the crap to drop into. Then the insepction plate and take the whole linkage out comes off.

Do do a ring and pinion swap you need a big socket (I can't remenber the size, but it may be 24mm or bigger), and a breaker bar long enough so you can get some purchase on it. The very high clamping load on the bolt at the drive shaft side makes it best to use some ramps to loosen the bolts.

You firstly take off the drive shaft bolts (four of them) and pull the shaft out. (Leave the end at the tranny in so oil doesn't pour out of the trans).

Then you undo the bolt at the pinion end (as it goes into the diff)

As long as both wheels are on the deck or wheel ramps, the diff wont spin, and it'll be a cinch. At this stage, its a good idea to loosen off the ring gear bolts. If you have an LSD you'll have to raise both rear wheels to do this.

Then jack the car up real high, remove the wheel ramps, and add some axle stands, and rip both rear wheels off. After taking care of the rear disc or drums, remove the axles from the diff on both sides by undoing the four 9/16" bolts, and make sure you don't let the car roll on you or you'll be killed dead. (Chock the front wheels!)

Sometimes the axles are a bit stuborn to come out, but if you remount the wheel and give it a gentle whack it should come out okay.

When this happens, the ring and pinion is free to drop put the back. The bearings must not be mixed up, and the spacers must stay where they were before. The 2.77 ratio ring gear will come out, and the pinion gear can come out to. You'll find that all sedans after 1982 ran a crushable spacer, and that it can only be replaced by one of the same gender. Some diffs run a stepped shank, others run a crush ring. If you are just doing a simple swap, then XE/XF diff with the 3.23:1 ratio (ex 5-speed 3.3 Falcon) will bolt right on it. Set the torque specs to the required amount, use the correct diff fluid. Then replace everything in reverse order.

NB://If you are trying to do a 3.23:1 gear swop to a car originally with an LSD, then you need to check with a specialist. There are a few ins and outs here. Most cone clutch BTR/BW rear ends suffer from wear in this area, and its best to have it sorted before it screws up on you while your driving it. )

 

[Anonymous]

Dont the 2.77:1 diffs have 25 splines, and the 2.92:1 plus ratios have 28?

 

[xctasy]

I don't know for sure, but post '96 to the last 2002 AU BTR diffs were all 28 spline with 3.45,3.23 ratios.

Last 2.92:1 was manual V8 XE 351/XF 3.3 4-speed, XE EFI 4-spd. I didn't think the 2.92 ratio ever resurfaced. It was all 3.23 / 2.77 / 3.08/3.27 / 3.45 from then on.

Before 1996, every thing was 25 spline? Some V8's were four pinion, like the Commodore Turbo, which ran a 25 spline BW 78 with 3.45:1 ratio.

I think the 28 spline diff was a response to Holden and Fords loosing axles in Group E racing and rallying.

 

[addo]

You really need a spreader to get that centre out. It's usually (should be!) tight as.

Adam.

 

[Anonymous]

thanks for that seems easy enough... i changed my sisters escort diff centre and that was a peice of cake.... as long as this linkage doesnt need any fine tuning adjustments i dont think ill have any major probs...

cheers. hopefully wont be 2 long till ive done it

-matt-

 

[xctasy]

Adam is right about early BW 78 diffs. Early manuals on Falcon sixes from XK to XW showed the need for spreaders. I don't think you need to use them for the later ones. I don't know why.

Be sure and use either new or original bearings bearings on your housing. Use the donar diffs spacers. Backlash may be wrong otherwise.(Speaking of which, PM Backlash and ask him the goss...It's not Thursday, and he shouldn't be at the bingo. He's too young for that anyway)

 

[Anonymous]

Matt,
Diff work is a sh1t to do on those late diffs.
It can be done but not easy in the backyard situation.
Also setup can be difficult without the correct tools.
I rebuilt the diff in the XM coz it has screw adjusters and not shims.
If you fit new bearings then all the shims will have to be changed to set the preloads and the contact pattern.
Best to buy a centre and housing with the ratio that you want and just screw the other unit in. If you buy rebuilt or used is up to you.
Yes a housing spreader is required to remove the old centre and to refit the new centre with the bearings and shims.
Noel.

 

[Anonymous]

hey fellas..
diff change has come about alot sooner than planned and at a lot more of a cost than originally thought....

tuesday night i was unfortanate enough to blow my diff... luckily was still driveable... after ringing about 30 wreckers and about the same amount of diff and tranny mechanics, i discovered that firstly 3.23 center does not fit into a 2.77 housing!! aparently only a 2.77 and something around 2.5? something will fit in......
however a 2.92 housing will fit everything else.. so that meant changing the whole housing....
now the other problem was not 1 wrecker had a 3.23 coil sprung diff assymbly... some had leaf ones tho..... now after all my bullsh*t i was kinda fed up with it all.... called WA diff centre they gave me a price, i didnt have to suply anything just my car.... so its there now hopefully done tomorrow!!!! at not such a pretty price, but oh well ya get that...
guy there did sum quick figures for me and he heckons a 14% increase in in take off.... but 14% lower top end 14% worse fuel econ..... and the rest of thatjust thought id let yas know

have a good one!!!!
-matt-

 

[xctasy]

Good on ya. A salisbury diff requires a high level of expertise to get swapped over. That spend up of $$$ should give you a quiet diff which will last for years.

All the XD-XF Falcons were over geared, except for the 3.3 5-speed. It just had a crud quality Sigma/Crumydore four gearbox behind it to ruin it. In most slower speeds situations, a 3.23:1 should save you fuel. On the open road, it may hurt things a litre per 100 km, but you'll love the response!

 

[Anonymous]

ok verdict is in..... got my car back,. and the diff has made quite a notisable change!!1im very happy with it and im glad i decided to do it.... now my speedo is out by 20kmph but i can live with that.... and the noise sitting on 100 is awesome.... can be heard from 3 to 4 cars away!! hahahah

party hard people!
i will

-matt-

 

[Anonymous]

the speedo is easily fixed, just go to a ford dealer and get the speedo gear for a 3.23 diff. cost is under 10 bucks. i did the conversion a few years ago.

 

[Anonymous]

oh really...... hmmm if its easy enough then maybe ill fix it.... where does it go?? gearbox somewhere? is it as easy as you make it sound?? what sorta tools are we talkin?

-matt-

 

[Anonymous]

yeah its piss easy. the speedo sender is located on the side of the gearbox (cant remember which side). it has one bolt holding it in. to get the gear off theres a circular clip holding it on, just slide the clip off.
the colour of the gear should be purple which is for the 2.77 diff. u need to get the light green gear for the 3.23.
hope this helps.

 

[Anonymous]

yeah dude, its a piece of piss hey

just get under there, look for where the Tailshaft Thingy goes in, it'll be up to one side, drivers side if I remember right. Just look for something about the size of a matchbox, probably just a bit smaller, that has three wires and some red insulation tubing coming out of it, poking out the side of the tailshaft end in the gearbox. You'll need something small, like an 8 or 10mm socket to get the retainer bolt off, and it'll come out pretty easily. Just take the retainer clip off the speedo gear, and pop your new speedo gear on, remembering the retainer clip.. lol. It might need some jiggling getting it back into place, but nothing too strenuous.