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Arthur Mak



Member Since: 08 Sep 2016
Location: Hong Kong
Posts: 11

Hong Kong 2012 Defender 110 Puma 2.2 SW Orkney Grey
Swapping 4-pin rear differential gear to the front
Brothers, I am going to install an Ashcroft Air Locker to the rear axle of my Puma 110.
At the same time, I wonder could I swap the orginal 4-pin rear differential gear to the front (which is orginally 2-pin at the front). Is it feasible?
When I checked the diagram at LRworkshop, I noted that there was a "front differential gear housing" whihc does not exist at the rear axle, did the swapping job easy or need a lot of parts to buy?
Thank you very much.
Post #782830 24th Jul 2019 8:42am
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blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 16808

United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
No. A Rover diff can be fitted in a P38 housing but not vice versa.
Post #782835 24th Jul 2019 9:19am
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jst



Member Since: 14 Jan 2008
Location: Taunton
Posts: 7664

2011 Defender 110 Puma 2.4 USW Stornoway Grey
Post the fitting of the p38 rear diff casing, td5s 110s inwards, it's not a straight forward swap. I was under the impression You could build the centre into a std rover diff though. Cheers

James
110 XS Utility
130 Puma Station wagon/camper (in the making)
90 Puma Hardtop


Last edited by jst on 24th Jul 2019 9:41pm. Edited 1 time in total
Post #782867 24th Jul 2019 11:11am
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blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 16808

United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
You can certainly build a Rover centre into a P38 pinion housing, all you need is a spacer between the crownwheel and flange (which is why the same ATB or locker fits either).

To go the other way you'd need significant machining and I don't think there's enough material on the P38 diff for this.

You could modify the axle case and propshaft and fit the complete assembly, but it would be a bit daft to fit an interior short-nose pinion housing in place of a long-nose.

Best option is an Ashcroft ATB.
Post #782871 24th Jul 2019 11:33am
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jst



Member Since: 14 Jan 2008
Location: Taunton
Posts: 7664

2011 Defender 110 Puma 2.4 USW Stornoway Grey
Understood.

Best option surely is the the low pinion hypoid air locker! For off roading anyway! Cheers

James
110 XS Utility
130 Puma Station wagon/camper (in the making)
90 Puma Hardtop
Post #782987 24th Jul 2019 9:43pm
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Arthur Mak



Member Since: 08 Sep 2016
Location: Hong Kong
Posts: 11

Hong Kong 2012 Defender 110 Puma 2.2 SW Orkney Grey

Click image to enlarge


Maybe this picture can better show my question, can I use the red part to replace the blue part?

As I am going to install a airlocker in the rear axle, the whole red part will be replaced.
Post #782996 25th Jul 2019 2:11am
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blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 16808

United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
Arthur Mak wrote:
Maybe this picture can better show my question, can I use the red part to replace the blue part?

As I am going to install a airlocker in the rear axle, the whole red part will be replaced.


As I said above, tthe simple answer is that ig cannot be done.

Your rear differential is a P38 type, (or "short nose" diff). Your front differential assembly is a Rover type (or "long nose" diff). It is possible to fit the differential from your front axle into your rear axle pinion housing, but it is difficult (albeit not totally impossible) to fit the differential from the rear axle into the front pinion housing.

Although generally very similar in overall dimensions, the crownwheel on the P38-type diff is closer to the axis of the pinion by about 5mm. To fit the P38 diff into the Rover pinion housing you would have to do a significant amount of machining to the P38 diff carrier, making it generally impractical.

T!G UP on this forum has done it. These photos in his gallery show what needs to be done:-

https://www.defender2.net/gallery/thumbnails.php?album=967
Post #783017 25th Jul 2019 7:41am
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Merlin



Member Since: 30 Oct 2010
Location: Newmarket
Posts: 980

United Kingdom 
Can I fit a 4 pin diff to the front of a 2008 Defender as a direct replacement?
Post #803167 22nd Nov 2019 12:55pm
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Scotm



Member Since: 28 Feb 2014
Location: Aberdeenshire
Posts: 634

Scotland 2012 Defender 110 Puma 2.2 SW Orkney Grey
Post #803172 22nd Nov 2019 1:36pm
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Merlin



Member Since: 30 Oct 2010
Location: Newmarket
Posts: 980

United Kingdom 
Yes thanks. FYI they are on a 2 week turn round on builds. Peter.
Post #803176 22nd Nov 2019 2:19pm
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Chris86



Member Since: 15 Jul 2014
Location: South Yorks
Posts: 750

United Kingdom 2005 Defender 110 Td5 USW Chawton White
Hi,

It might be worth trying Winchester Gears in Rotherham- they tend to have a reasonable amount of stock and I can vouch for the quality of their work being spot on.

Regards

Chris
Post #803207 22nd Nov 2019 5:06pm
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