Changing the diff ration on a dually rear end?

[Wickmyster]

My father and I fitted and LD28 and 5 speed to a CF2 bedford jumbo, but it revs to high on the open road. Are there any known centres to fit into it? What company manufactured the diff? Any help or ideas would be appreciated!

[johnxb351]

Hi Wickmyster.   When you say LD28  do you mean a diff out of a Nissan van  or light truck ?.   Some diff have a thin metal tag at the diff filler plug with the diff ratio and maker of the diff  info on the tag.  If its out of a nissan and you know what model van or truck its out of  Nissan might be able to tell you who the maker is and might have diff ratios info.  if  Nissan does not help you the i would try a diff rebuild  specialist.   In  5 gear at a 100kph what rpm is she  doing ?  ,  what engine has she got ?.

[Wickmyster]

No LD28 (2.8L Nissan 6 cylinder diesel engine). It is running the standard dually diff. That is the diff we are trying to change the ratio on.

[BedRover]

G'day, LD28 is an interesting option, have thought about it myself, will be interested in your thoughts in the long term. As for beddy diffs, they were all pretty short..4.45 to 5.29 from memory, great for dragging hills into view but not great on the hiway. Plenty had Holden converts...usually Salisbury's out of 1 tonner's, not sure what happened there across the ditch. There may be an easy option of changing the centres but I have gone to 9 inchers in the past, (behind 350 chev/T350) which can handle the weight of the LWB. The Holden option will give you the wider ranges of ratios/cheaper and easier to find, with the low hp/torque/rpm of the LD28 nearer to 3.08 or even 3.55 to give more pulling power...all this depends on your wheel/tyre size as well and what you are making, cruiser or camper? Give us a bit more info on what you are chasing, end result and $$ to spend and I will see if I can remember stuff. I have been away from them a while and there are prob more options these days that other BUGA's will know of.

Keep us informed and goodluck, Cheers.

[Wickmyster]

We are making a camper but will do lots of open road driving with it. Nothing to heavy and no towing etc. We want to keep the 14' dual wheels, so changing just the centre would be the ideal. That way we can keep the big drums and don't have to mess with the front end. It pulls sooo much better than the 2.3 diesel we pulled out of it. So a holden salisbury diff centre would fit? that means some land rover diff centres would fit also?

[Zeeman]

I believe Borg Warner centres are most commonly used for the conversion. The side gears have to be modified to take the Bedford axles which is where it starts to get expensive.

[BedRover]

Ok, a camper, nice one. Um no, I was referring to a complete Salisbury rear end change from drum to drum. So yes to your other Q... Landy diffs (3.54 RRC/Defenders etc) would fit but you are going down the road of wheel changes etc. Salisbury 1 Tonners are not as big physically but should handle the work duty of your camper. Bedford over engineered their drivetrains and from memory the dually has a heavy casting frontal diff, meaning you pulled the gearing out from the front, tailshaft side rather than the rear as in most BorgWarners, so I can't answer to Zeeman's comment on $$ and flow on effects, like I said before there is much that has happened since 'my day'.

I put in a 9 incher out of a Gallaxie, converted stud pattern to Commodore and fitted singles, 245/75-15's, with the larger tyre you are raising your distance covered and therefore lowering your revs for the same speed. You have said that you have the 5 speed so an overdrive is already in the mix, so IF there is no easy centre change then to keep the big drums will mean losing the duals, which does change look and flows on to the front end...which is what I did,  but I lifted the front springs as well and went semi-offroad style.

I am still hoping for you that there is a centre change out there...anyone in the UK with some info??

[rumax]

Best bet would be to talk to BusyKiwi, as he is on your side of the ditch and know what is available there.

[Marky]

My cfl.. I changed the Salisbury to Chevy 12 bolt but w bedford axels n 10" drums.. I run..single 10"x295/15..cruising da hwys

[shaginwagin]

Changed the diff in beddie, diff man used a borg warner  hx 1 tonner, as it has a stronger tube, and had it widened to suit the front track. You can then get whatever ratio that you want, and i carry a spare axle in the back if needed. Can fit hq disc's straight on if you want.  As I have all vn I have disc's all round.