Changing a Diff Centre?

[krozbolt]

Hi guys, I'm a new MK1 Owner from Melbourne, Australia. For my first Post I have a question:
My Mk1 has a manual 4.1L Ford Falcon engine. Goes real good but revs like anything on the Highway.
Is changong the diff centre the best thing to do to make it rev lower?
I already have bigger wheels on order.
And if so, where do i get a new centre from?

[FredTransit]

Welcome! Madmark's your man for diff ratios. I think you will get away without needing a carrier for the diff gears on a Mk1, or you could change the whole axle for Mk2 and get a newer brake set up too.

[MrMPuk]

To be honest we probably aint alot of help due to you being in Auz but you might find one of the members from your neck of the woods might be able to assist.

[Sundowner]

Aussie 250ci transits had 3 ratio options 3.89, 3.7 and 3.5
There should be an ID tag on the rear that will have the ratio

Im pretty sure that the aussie 250 transits share the same 25 spline diff as the XD-F falcons so finding a 2.78 should be no worries

I have a 3.0 final drive in my mkII and the 250 has no problems pushing it

[browneye]

hey krozbolt, i got a transit with a 4.1L falcon eng in it aswel, however mine is running a 3speed auto. and im in Australia, melb.\

havnt taken her on freeway yet, but i am pretty sure i will be havin the same issue as you, espec because of the 3spd.

Do you know what gearbox you are running?
and also, what wheels do you have on order, my transit is at the moment got some 5studs, pretty sure they are stockers with the small centre hub caps and all. but im lookin to get bigger wheels also, where you getting yours off?

also, your best bet for a diff centre is the wreckers, ive found heaps of stuff for my transit from the local wreckers, and if they are the same as ford xd-f, there are heaps of them there you could rip out off, will cost dick all too.

Cheers.

[madmark]

you guys are lucky with those ratio,s try haveing 4.1 4.56 4.63.5.14 5.83 these will get your engines reving !

[cad69]

Howdy

I'm running a 4.1 with 4 speed top loader. Was told my diff had been changed to better cruising diff previously. I can sit on 120K's with plenty of punch left in her. Not sure what ratio it is or how I find out but the housing looks standard and still running 6 stud wheels. I spoke to diff specialist today about changing to a LSD and apparently it can be done but will cost about $1500Au. He mentioned it was a Borg Warner centre. still trying to work out whether to put an electric winch on the front or change diff. Sorta reckon that jumping out in a creek at the top end to tie the cable to tree or something could make me croc bait.

Remember if you change diff you speedo will be out. Hang on that's a point, my speedo reads 42K's/hr when I'm doing 60 so the diff gearing has been reduced by little under a third. So as Sundowner says it might be running a 2.78 which I reckon is perfect. I'm running gas and it's not a crossflow head and still I can lay rubber.

Cad

[madmark]

over were you are your axles are not the same as the old english noisey jobs!

[FredTransit]

How about an Oz forum Luke, looks like the poor sods don't have anything over there, not that they are not welcome!

[Luke]

How about an Oz forum Luke, looks like the poor sods don't have anything over there, not that they are not welcome!

Lets not discriminate fred the poor sun drenched sods can post will us lot!! a transits still a transit even if its got a dodgy diff!!!

[FredTransit]

Wasn't meaning to discriminate, just make a bit of an extra area. Hey, how many nationalities have we got now?

[Luke]

how many nationalities have we got now?

Well incase you wondered!!! (from last month)

Great Britain gb 17674
United States us 17186
European Union eu 3702
Australia au 397
Finland fi 304
Italy it 431
Hong Kong hk 226
Netherlands nl 153
Switzerland ch 138
Belgium be 63
Czech Republic 58
Ireland ie 47
Canada ca 33
Norway no 20

I think you will find the USA slightly incorrect - its where the server is based!!!

[browneye]

oy, get back on topic, i liked reading about all this diff stuff.

and cad69, lay rubber you say.... my beast aint rego'ed yet so i havnt been able to take for a decent run, but im runnin a non cross flowed 4.1, unfortunatly with a 3sp auto, what gbox is your 4 speed top loader out of? it should bolt straight up shouldnt it?

[cad69]

Ain't got a clue about where the top loader box came from but they were a pretty standard box in the early seventies so thinking XW XY and XF series. Would bolt straight on but may have to change flywheel. Look at Continas too. I had a worked ferry 302 and the 250 cortina's ran rings around me which gave me the mighty shiits. My Tranny sits at 60K's (35mph) very comfortably in second gear with 2 more gears to go. OD wouldn't be bad. Probably would make the ton (160k's) but steering and brakes would be a bit dodgy. You may find it easier to change engine and box as one complete unit. Probably cost same as well. Stick sticks out between seats behind handbrake. Need clutch pedal and probably different brake pedal. Nothing that grinder and Oxy wouldn't fix. Crossflow would be good but then exhaust would have to be changed.

Hung a canvas water bag off my bull bar. I look like outback jack!

Cad

[Sundowner]

If you want a 4 speed go a single rail from a CORTINA as the stick is in the same place as the transit one or if your really keen you could go for a 507 Borg Warner 5 speed from an XF

you need to cut one of the floor braces to fit the 4 speed

With the 4 speed and 3.0 gears the 250 is pulling about 1800 rpm at 100km

If you want to go a cross flow all you need to change is the engine pipe the exhaust is still on the same side as the 250 log