will_warne Posted October 24, 2005 Share Posted October 24, 2005 Quick question really. I found a brand new P38 spec rear axle at Sodbury for a good price so its now sitting in my garage. I bought it becasue I knew it was straight and its already stronger than a standard coiler axle (diff pan is much thicker, as is the bottom of the bottom of the axle arround the diff) although that won't stop me breathing on it the questions I've got ate about the diff. A standard coiler diff housing won't fit without a few mods (very doable, though) but I was wondering if a P38 crown wheel and pinion is stronger? Are they any differant from old style ones (ie are they interchangable in the field). If so, I'm sure I've heard you can fit an RD56 ARB airlocker (ie what I've already got) into them but I think I may need an adaptor. Is that right? TIA, Quote Link to comment Share on other sites More sharing options...
SteveG Posted October 24, 2005 Share Posted October 24, 2005 Hi Will Is it a rear 110 P38 axle/Wolf or a Range Rover P38 axle, as they are similar but different. Internals are the same as I understand but diff housing and obviously axle are different. They are 24 spline, 1.24" diam, 4pin and stronger than standard 90/110 fair apart from Salisbury with 3.54 R&P ratios. As for ARB locker, you need RD57 not RD56 for this diff. Not sure what difference is,but both Dave at Ashcrofts and Simon at Devon 4x4 have installed the RD57 locker and would know difference and whether you can adapt your RD56. If it helps the flange diameter is 205mm [8.07"] and RD57 was developed for axles with Traction Control. Cheers Steve Quote Link to comment Share on other sites More sharing options...
Jon White Posted October 24, 2005 Share Posted October 24, 2005 If P38 axles are the same as Disco II axles then as far as I'm aware standard diffs will fit into these. A mate of mine has Disco II axles under his safari racer and he simply uses standard 4.7 series diffs in it so far as I'm aware. I'd guess he probably changes the centres over as I'm guessing that the later shafts are all 24 spline. HTH Jon Quote Link to comment Share on other sites More sharing options...
BogMonster Posted October 24, 2005 Share Posted October 24, 2005 The diff is obviously different but I don't know if they are interchangeable into the axle casings or not - I know the diff pan on a new 110 rear axle is bigger than the normal 90 one so there might not be clearance inside a std axle. You'd also need a new prop as the nose of the P38 diff is much shorter. I looked into ARBs a while back for somebody who wanted them on a new sort of 110 and IIRC you fit an RD56 and some sort of spacer ring to make it go into the P38 type 4 pin diff. The guy decided not to fit it so I haven't any first hand experience but the advice came from Ashcrofts so I suggest you talk to them - Dave knew what was needed. The Disco 2 axles use std 2 pin diffs as found in a 90, not the P38 type diff, so they will take any normal 90 or Series pattern diff. Just dug through old emails and Dave Ashcroft said "use the normal RD56 ARB together with an adapter ring which we supply at £25" simple as that Quote Link to comment Share on other sites More sharing options...
will_warne Posted October 24, 2005 Author Share Posted October 24, 2005 The diff is obviously different but I don't know if they are interchangeable into the axle casings or not - I know the diff pan on a new 110 rear axle is bigger than the normal 90 one so there might not be clearance inside a std axle. You'd also need a new prop as the nose of the P38 diff is much shorter.I looked into ARBs a while back for somebody who wanted them on a new sort of 110 and IIRC you fit an RD56 and some sort of spacer ring to make it go into the P38 type 4 pin diff. The guy decided not to fit it so I haven't any first hand experience but the advice came from Ashcrofts so I suggest you talk to them - Dave knew what was needed. The Disco 2 axles use std 2 pin diffs as found in a 90, not the P38 type diff, so they will take any normal 90 or Series pattern diff. Just dug through old emails and Dave Ashcroft said "use the normal RD56 ARB together with an adapter ring which we supply at £25" simple as that Thanks BB, I was just on the phone to Dave but forgot to ask him..... Quote Link to comment Share on other sites More sharing options...
fisha Posted October 25, 2005 Share Posted October 25, 2005 isnt the diff on the wrong side too? plus the rear trailing arms are very different on the P38 as well Quote Link to comment Share on other sites More sharing options...
BogMonster Posted October 25, 2005 Share Posted October 25, 2005 I think you might be right D2 diff must be on the same side as Defender because it uses an LT230 t/box but I think the P38 might be the other way round? Also what is the rear suspension arrangement on a P38 is it like a Disco 2 i.e. radius arms and Watts linkage, or is it lower links and A frame ball joint like a Defender? The nearest P38 is about 1000 miles away so I can't look Quote Link to comment Share on other sites More sharing options...
Guest diesel_jim Posted October 25, 2005 Share Posted October 25, 2005 The nearest P38 is about 1000 miles away so I can't look And that's 999miles too close!! Quote Link to comment Share on other sites More sharing options...
will_warne Posted October 25, 2005 Author Share Posted October 25, 2005 Thanks guys, i forgot about the diff being on the wrong side on a P38 RR. The mounts for locating the axle aren't an issue; they're all coming off anyway The plan is for 4 link at the back and either 3 or 4 at the front. Annother bonus of this is I'll be able to see how the setup works on Moglite and make any adaptions to my design I want to do. Quote Link to comment Share on other sites More sharing options...
SteveG Posted October 25, 2005 Share Posted October 25, 2005 isnt the diff on the wrong side too?plus the rear trailing arms are very different on the P38 as well Hi Donald I'm sure Will would have spotted that,that's why Isuspect he has a 110 rear P38 axle. Same internals as a Range Rover P38 axle Cheers Steve Quote Link to comment Share on other sites More sharing options...
fisha Posted October 26, 2005 Share Posted October 26, 2005 ah - i understand. In answer to BogBusters question. P38 uses radius arms plus a panhard rod on the rear ( dont think its watt linkage IIRC ). The radius arms grab the axle in a straight line underneath it at about 4 oclock and and 8oclock positions. Arms are a composite resin i think ( they aren't metal on the outside at least ) Quote Link to comment Share on other sites More sharing options...
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