Is a bmc mini tractor & Leyland 154 complete diff the same

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fordfan_300
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Is a bmc mini tractor & Leyland 154 complete diff the same

Post by fordfan_300 » Sun Jun 06, 2021 12:05 pm

Hi can anyone tell me if a complete diff from where it bolts to gearbox on a bmc mini tractor and a Leyland 154 mini tractor please looks the same



Ley154
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Re: Is a bmc mini tractor & Leyland 154 complete diff the same

Post by Ley154 » Tue Jun 08, 2021 7:50 am

Hi, the whole back axle is the same with one exception. Very early Minis had a single speed pto and the selector mechanism within the axle casing is simpler than the dual speed set up. It can be interchanged as a whole unit together with the different pto shaft. So, if you have a good Mini axle and a worn/broken 154 one you can swap them. The final drive ratio never changed throughout the whole range. The only thing not to do is to change just a crown wheel or just a pinion as they are matched paired sets. John Poulter

fordfan_300
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Joined: Thu Feb 25, 2021 9:08 am
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Re: Is a bmc mini tractor & Leyland 154 complete diff the same

Post by fordfan_300 » Tue Jun 08, 2021 2:49 pm

Hi John, I want to put the complete diff from the BMC MINI from the back of gear box onto the leyland 154,
the BMC MINI is a 3 point Linkage with a PTO shaft,the Leyland is a backhoe so i realy need to remove the PTO shaft and put the plate which is on the leyland diff, MY next question is does the PTO shaft just pull out the back when you undo the bolts?
You have been a great help John,parts are a bit scarce here but i have managed to find a BMC mini

Ley154
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Re: Is a bmc mini tractor & Leyland 154 complete diff the same

Post by Ley154 » Tue Jun 08, 2021 5:06 pm

Let me understand exactly what you want to do. I presume the backhoe is some aftermarket unit ( Lewis or McConnel?). If the unit doesn't have a separate pto driven hydraulic pump like most then I assume you have to rely on the tractor hydraulics? If so, just out of interest do you get problems with only 2 galls of oil in the whole system?
I think you are saying you want to take the diff assy including the crown wheel and the matching pinion assembly with its bearing housing and fit them into the 154 axle casing. Why not just swap the whole axle complete? You can pull the pto shaft out but it will leave either a collar ( single speed) or a gear ( two speed) loose in the front end of the axle casing. As you will be splitting the box this will not matter as you can just remove all the bits you don't want before reassembling. You will definitely need to read the relevant pages in the manual about setting up the crown wheel backlash and pinion bearing preload. A selection of different thickness gaskets for the axle trumpets are used to get the diff carrier bearing preload and backlash. Do you have access to these?
A photo of the tractor would be nice. What exactly is the current problem? Have I gone off on an irrelevant tangent?
Lastly what are you going to do with the rest of the tractor? Regards John

Ley154
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Re: Is a bmc mini tractor & Leyland 154 complete diff the same

Post by Ley154 » Tue Jun 08, 2021 5:08 pm

Forget the last sentence I have just noticed you are not in the UK. John

Ley154
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Re: Is a bmc mini tractor & Leyland 154 complete diff the same

Post by Ley154 » Tue Jun 08, 2021 7:18 pm

Now I realise you are in Australia is your digger a Cranvel or Inmac? Pity they never got imported to the UK. A photo would be nice. John.

fordfan_300
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Re: Is a bmc mini tractor & Leyland 154 complete diff the same

Post by fordfan_300 » Tue Jun 08, 2021 10:50 pm

John i want to put the whole diff casing complete onto the leyland wheel one diff off one tractor onto another.
the front end loader and back hoe is a local company it has a big oil tank behind diff and the hydraulic pump is driven off the front off the motor

fordfan_300
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Australia

Re: Is a bmc mini tractor & Leyland 154 complete diff the same

Post by fordfan_300 » Tue Jun 08, 2021 11:04 pm

one more thing will the PTO shaft just pull out the rear of the diff when you undo bolt round the seal
Thanks John

Ley154
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Re: Is a bmc mini tractor & Leyland 154 complete diff the same

Post by Ley154 » Wed Jun 09, 2021 8:55 am

Hi again. To remove the pto shaft first put the selector in 1000 rpm and tie it there. Undo the 4 nuts that hold the pto support casing to the back axle. I attach something onto the splines and use a slide hammer to pull the whole assembly out. You don't pull just the shaft from the support casing. If you are not going to replace the shaft then you will have to split the axle and gearbox ( which you are going to do anyway luckily) and remove the lower drive gear otherwise it will remain loose and result in a whole load of smashed gears. The whole selector mechanism can be removed as well if you have the appropriate blanking cover. This is all covered in the manual - there is a free download of the Mini manual which covers everything apart from the engine here on this site I believe. You must get one and read it, there are quite a few pages covering the back axle.
There are two types of back axle. The standard one has just the disc brakes. The industrial one has additional drum brakes on the end of the axle tubes which may well be the case with your digger. This type of axle not only had the extra drums and backplates but different axle tubes and different final drive shafts. If you install the crown wheel and differential carrier from the Mini but retain the axle tubes from the digger you will have to reshim using the different thickness paper gaskets to get the diff carrier bearing pre-load and then the gear backlash correct. John Poulter-

fordfan_300
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Re: Is a bmc mini tractor & Leyland 154 complete diff the same

Post by fordfan_300 » Wed Jun 09, 2021 10:23 am

thanks again John

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