Transit dual wheel diff

[lewy]

Hi All,
Does anyone know anything about the old transit van dual wheel diff from i think the 70's era.
How strong are they compared to bedford diffs?
I'm looking for a strong dual wheel highway diff for towing and have found a transit that i might be able to get.
The back plate on the diff has 12 bolts, its slightly oval shaped but symmetrical and looks biggish.
Anyone know what ratio they are and if it would handle a 400 chev, i will be using a t700 auto so will have overdrive.
Any other ideas as to what diff i could use; I'm hoping for a 3.5 or 3.7 ish ratio.
Was trying to get a f350 diff but most have been around 4.1 or 4.5 and think it will rev too hard on highway. F350's use large diameter tyres and i was going to use low profile tyres if using this one, the 400 chev has been built for low revs.
Any help appreciated
Cheers Lewy

[Bas NZ]

Hi, In New Zealand they used the Transit diffs in Drag cars, so they must be strong. But very low ratio close to the bedford, would need overdrive on auto ( can get an overdive unit for the T-700 from the States  or 5 speed box would work on the low ratio. The advantage with low ratio diff and then overdrive or 5 speed is that you almost double your low down power, but run out around 80k, then the overdive kicks in or you put it into 5th gear. With the high diff ratio you would have less down low power. This is what I have found, my thoughts only. PM Ben on her he might have a dual wheel diff with high ratio. Ok sorry one other thought, would have to check this out but think the Pontiac diff can be used and the bedford dual axels fit straight in.

[lewy]

Hey Bas, thanks for your input. The T700 is meant to be an overdrive box and this one will have lockup in 4th too.
I am now trying to find 15 or 16 inch rims for the transit diff as larger wheels will gear it up too.
I havnt heard about the Pontiac diff fitting bedford, any idea as to what year Pontiac this might be.
Thanks again Bas for your info.

[Bas NZ]

No Problems Lewy, will try to find out the year diff used, there is a Bedfords running around my area with this done to them. The T700 over here don't have the overdrive unit on them but is available as a bolt on. Cheers

[BlackBedford]

G'day

There was a lot of info on the old site about Transit diff conversion but I will try to remember.

The early Transit dual wheel diff is
narrower than a CFL diff
same stud pattern
has much larger wheel bearings

The early Transit single wheel diff is
same width as a CFL diff
same stud pattern
shorter wheel studs
has much larger wheel bearings

To fit a Transit diff you need to get a single wheel 6 stud diff and a dual wheel diff.
Take the wheel studs out of the dual wheel diff and put them in the single wheel diff.
Move the spring mounts and you will be in business. The diff ratio is about the same so you will need an overdrive. The big advantage is greatly increased overload capacity for the truck.


 

[ben]

that sounds like the go lewy:)

i had a transit and it had a single wheeler, had a much better ratio than the 4.9:1 thou.

ben