Diff Centre Conversion

[Jock]

Spent a couple of days converting my diff centre over the weekend.
My LWB has a converted Bedford diff with a Borg Warner centre. We changed the ratio form 3.89:1 to 3.45:1

Previously the van would sit on 3800 revs at 100klm/hr now she sits at 3000 revs at 100klm/hr.
Still has the grunt to get up the hills, coupled with the trimatic I wouldn't go any lower than 3.45 you may start
to lose pick up off the mark and hill climbing ability.

I was going to go 3.23:1 - VERY GLAD I went for the 3.45 ratio.
Here are some pics.

Got rid of the bullbar too - horrible job they did welding that to the front of the van!






Up she goes... Found out I have 'coil over' springs - yay.






Made a holder to remove the pinion with ease.


Axles out.


Diff centre (crown wheel and pinion) removed. Notice the weld marks on the axle housing where the diff was joined.


Big old LWB drums...

[John Abbott]

Top pics Jock.....Thats one big lump of a diff housing!!  cheers...johnno

[westy12]

gday jock i agree with the up hills bit! ive got a 3.08 and it is slow up hills. take off at lights is slow too but im never really in a hurry! i sit at 2700 at 100 which is good, but im thinking of trying a 3.36 and compare it for economy. how much was it to convert your ratio? have a good one, luke

[Bas NZ]

Jock, sorry for not knowing what are you running 6- 202 or 8, if 6 I have the same, well close 3.5 and it works well for me, mind you my motor is worked but then this is off set by the size off the Beddie.

[Jock]

Westy,

The cost to convert was $100 - that was the cost of the new crown wheel and pinion on Ebay.
Get this, the guy was meant to send me a 3.23 set of gears and he muffed up and sent me a
3.45 set. At first I was annoyed but now I am STOKED! Sometimes you get lucky.

All the work was done by my cousin and I and it took us a couple of days on/off.
I would say a full day if you stayed at it constantly.

I replaced the bearing on the pinion but that was at no cost as my cousin owed me a favour.
All other bearings were in good condition and did not need replacing.

So all up I got out of it for $100.

If you get the gears and you have a workshop you can do it yourself. It is a 2 man job.
We used a forklift and some wooden blocks with a V cut in them as a workbench.

The quotes I received from Diff shops went from $400 - $1000 and all said that it would take a full day.
I figured my cousin has the know how and the workshop so why not lean on him for a favour.
I helped him out with his website and will continue to do so. He helped me out with the Beddy and will
continue to do so... That's what family does, help each other.

Jock



Bas,

I am running a 202 straight 6. My motor is worked too, and I am getting better top speed from the 3.45 ratio.

Jock

[Jock]

Westy - 3.36 would be good too but no lower with the straight 6 and trimatic or m21 box.

Jd

[BlackBedford]

G'day

You have done well.
I got charged $1300 to rebuild my Borg Warner dually diff, and they didn't do real good job of it.

What are you going to do with the big bullbar?

Regards
Chris

[Jock]

Chris,

I am very lucky that my cousin is a mechanical engineer and has been working on cars for years.
He was able to check the gear mesh and back lash and he knew how it was all meant to be.
He has a bearing press and all necessary tools too!

Luckily we didn't run into any problems, just a couple that were my fault LOL

The bull bar is in Cowra at the moment in my cousins yard. I was going to keep it as no one wanted to
buy it when I tried to sell it last year - now that I think about it, I blame the crap classifieds system on old buga
for the bull bar not selling. What is it worth? It is a fair size.

Jock

[ben]

yo jock i noticed you said

If you get the gears and you have a workshop you can do it yourself. It is a 2 man job.

but then you said

He was able to check the gear mesh and back lash and he knew how it was all meant to be.
He has a bearing press and all necessary tools too!

sorry to be picky but are you serious that someone like me and my mate could do this sort of conversion?
was it nessesarry to pull the diff out of the van in order to do? or do you think you could survive with a hoist?

what other tools would i need other than a bearing press that i possibley dont have?

great work bro!


i have access to a salsbury 10 bolt disc brake complete diff for good price. only problem is its 2.78 ratio. thats the only reason why i ask hey.

ben

[Jock]

You could leave the diff in the van but it would be hard to work on it from down low.

We removed the diff and put it up on 2 blocks of wood on the forklift for
easy working. Forklift doubled as a work bench.

If you jacked the van up quite high and sat it on some high stands that would be the go.
A proper vehicle hoist would be ideal - then you wouldn't have to remove the diff.

If it was a straight out ratio change and your old diff was in good condition you could do it
with one man with a proper vehicle hoist.

We cut the old bearing off the pinion with an oxy and pressed the new bearing onto the pinion
with a hydraulic press.  If your bored one day - make your own hydraulic press - all you need
is some steel and a bottle jack and a welder, I'd say you have all three lying around.

It went a little something like this:

1. Remove diff hat/cover
2. Slide axles out so that they are not meshing with the centre gears.
3. Remove bearing caps - (mark bearing caps and diff so that bearing caps goes back to correct sides)
3. Remove diff centre assembly.
4. Check bearings for wear.
5. If bearings are ok proceed to remove crown gear.
6. Replace crown gear with new crown gear.
7. Remove pinion (may have to make a holder to get it out)
8. Replace pinion with new pinon and new bearing.
9. Put the pinion back into the diff housing.
10. Put the diff centre assembly back into diff housing.

There are a few more technical bits and pieces of info to take on board.
Remember - I am only a phone call away and my cousin is only a phone call away from me! LOL

1 man job with a hoist. I would love to have a hoist...

Jock