90challenged Posted April 20, 2007 Share Posted April 20, 2007 is there a simple way of working out what ratio your diff is without removing everything on the front? was thinking there must be a way of measuring how many revolutions of the wheel you get per turn of the prop. any suggestions more than welcome. thanks. Quote Link to comment Share on other sites More sharing options...
Lewis Posted April 21, 2007 Share Posted April 21, 2007 If the rear diff is a known quatity (or one in another car for that matter) you could chock one side of the car then spin the diff noses and compare the number of revolutions of the road wheel for a given number of propshaft/diffnose revolutions Lewis Quote Link to comment Share on other sites More sharing options...
90challenged Posted April 21, 2007 Author Share Posted April 21, 2007 sounds pretty good, the problem is ive got myself into a real situation. i blew the front on a play day. i then replaced this with another, i compared the old and new before putting them in and they looked the same (pretty stupid now i think about it). i put it in and went for a test drive on some green lanes. after about 1/2 hr the back blew which makes me think that either the rear was either severely weakened in the incident that blew the front or ive been a real dipstick and put the wrong ratio diff in the front. the only way to tell is to do what you suggested and compare it with another before i take it out of a donor vehicle. the problem im having is tracking down second hand ones. thanks for your quick reply. Quote Link to comment Share on other sites More sharing options...
BogMonster Posted April 21, 2007 Share Posted April 21, 2007 The diff will most likely only be either 4.7:1 Series diff or a standard 3.54:1 and you should be able to tell the difference between them using the prop revolutions: 10 wheel revs will either produce 35 or 47 prop revs. Counting the pinion and crownwheel teeth is of course the "correct" way but unless you have a "special" there are only two factory diff ratios and the vast majority of diffs out there will be the 3.54:1 which is what has been fitted in all 90/110/Defender, RR and Discovery vehicles. Quote Link to comment Share on other sites More sharing options...
rekab69 Posted April 21, 2007 Share Posted April 21, 2007 The diff will most likely only be either 4.7:1 Series diff or a standard 3.54:1 and you should be able to tell the difference between them using the prop revolutions: 10 wheel revs will either produce 35 or 47 prop revs.Counting the pinion and crownwheel teeth is of course the "correct" way but unless you have a "special" there are only two factory diff ratios and the vast majority of diffs out there will be the 3.54:1 which is what has been fitted in all 90/110/Defender, RR and Discovery vehicles. Hope this isn't classed as highjacking a thread as on other forums.... I was just about to post a similar question, can you mix axles..? I have a 98 110 TD5 bent rear axle, it looks to have tubes pressed into the diff housing, the 2nd hand one I just bought has a moulded all in one casing, if the ratios are the same I guess it can be fitted...? If it turns out to be wrong and it will fit yours maybe we can help each other out here...?? Regards Dave Quote Link to comment Share on other sites More sharing options...
Lewis Posted April 21, 2007 Share Posted April 21, 2007 Counting the pinion and crownwheel teeth is of course the "correct" way but unless you have a "special" there are only two factory diff ratios and the vast majority of diffs out there will be the 3.54:1 which is what has been fitted in all 90/110/Defender, RR and Discovery vehicles. I have a pair of 4.1 ratio diffs from an ambulance, aparently a few 4.1 factory diffs were produced Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted April 21, 2007 Share Posted April 21, 2007 I have a 98 110 TD5 bent rear axle, it looks to have tubes pressed into the diff housing, the 2nd hand one I just bought has a moulded all in one casing, if the ratios are the same I guess it can be fitted...? That sounds like a Salisbury axle, only fitted on the back of LWB's from late S2 to late 110's. No you can't mix diffs from them as they're physically different to the Rover axles. As for the original post, if it's a Range Rover, Defender or Discovery diff then it will be 3.54:1, I would think a Series one would be obviously different next to a coiler one as the ratios are different. Jack one wheel up and spin it to count prop revs, it's not rocket science. Everything coiler is 3.54:1, everything Series is 4.7:1 with the exception of Stage 1 V8 (3.54:1) and 101/FC which you wouldn't have one of anyway. Quote Link to comment Share on other sites More sharing options...
rick Posted April 22, 2007 Share Posted April 22, 2007 Hope this isn't classed as highjacking a thread as on other forums.... I was just about to post a similar question, can you mix axles..?I have a 98 110 TD5 bent rear axle, it looks to have tubes pressed into the diff housing, the 2nd hand one I just bought has a moulded all in one casing, if the ratios are the same I guess it can be fitted...? If it turns out to be wrong and it will fit yours maybe we can help each other out here...?? Regards Dave further to Fridge's reply, so you've bent the axle housing and you want to swap another in ? sounds like the one you have aquired is out of either a 90, Disco or RRC which is a Rover axle and no where near as strong as a Salisbury 8HA, which is what you would have in your 110. Also the pinion nose is shorter on the Rover housing, so the tail shaft will be too short to fit, although it will physically bolt in. How bent is the housing ? Is it easier to straighten and repair it ? Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted April 22, 2007 Share Posted April 22, 2007 A salisbury is cheap enough to find, they don't damage easily (I'm impressed you bent one) and you can make a drum-braked one disc-braked using off-the-shelf parts (search this forum for how). Pay no more than £50 for a salisbury axle, usual rate is about £30 as most people can't be bothered tripping over them / moving them out of the way disc braked ones may be a tad more but eBay & the forum classifieds are your friends Quote Link to comment Share on other sites More sharing options...
rick Posted April 22, 2007 Share Posted April 22, 2007 A salisbury is cheap enough to find, they don't damage easily (I'm impressed you bent one) and you can make a drum-braked one disc-braked using off-the-shelf parts (search this forum for how). Pay no more than £50 for a salisbury axle, usual rate is about £30 as most people can't be bothered tripping over them / moving them out of the way disc braked ones may be a tad more but eBay & the forum classifieds are your friends not quite that cheap here. at those prices, some enterprising soul over there should start buying them up and flogging them to the Yanks as lightweight Dana 60's Freight could be a killer, 'though Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted April 22, 2007 Share Posted April 22, 2007 IIRC a Salisbury is a dana-60 if that helps you any? Salisbury were bought by Dana (or they were bought by someone who was then bought by Dana) and I'm almost certain the Sals is a (not super strong) incarnation of the D60. Quote Link to comment Share on other sites More sharing options...
rick Posted April 22, 2007 Share Posted April 22, 2007 actually, I think the story went it was made under licence by GKN for Rover. CWP is interchangeable, carrier bolts are 12mm instead of 1/2" UNF, I think the pinion bearing is slightly different and the pinion spline count is different. Oh, and a Sals uses the weak Rover axle diameter and spline count. Axle tube diameter/wall thickness might be a bit lighter too. Was all said very tongue in cheek. Yanks wouldn't go for 'em anyway as a Sals is too narrow for their tastes. Quote Link to comment Share on other sites More sharing options...
Ex Member Posted April 24, 2007 Share Posted April 24, 2007 Real story......... The differential in question was designed by the Salisbury Axle Company, which was purchased by Spicer in the 1918. Spicer became Dana in 1946. The "salisbury" axle used in Rovers have a Dana Model 60 differential. The axle assemblies are built by GKN which has many close ties with Dana. http://www.dana.com/centennial/timeline/early.shtm Quote Link to comment Share on other sites More sharing options...
Michele Posted April 24, 2007 Share Posted April 24, 2007 not quite that cheap here.(...) Freight could be a killer, 'though Ditto! BTW,I'm after a Salisbury axle to fit a coiler... Quote Link to comment Share on other sites More sharing options...
Robtho Posted April 18, 2017 Share Posted April 18, 2017 Does a 1994 Discovery rear diff have the same ratio that a 1996 p38 has as Im looking to swap the diff out of my P38 RR. Thanks Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted April 18, 2017 Share Posted April 18, 2017 They don't fit, unless you do a load of machine work. Quote Link to comment Share on other sites More sharing options...
landroversforever Posted April 18, 2017 Share Posted April 18, 2017 I think they are the same ratio. However the P38 casing is different and the bolt pattern is different. Quote Link to comment Share on other sites More sharing options...
Snagger Posted April 18, 2017 Share Posted April 18, 2017 On 21/04/2007 at 5:24 PM, BogMonster said: The diff will most likely only be either 4.7:1 Series diff or a standard 3.54:1 and you should be able to tell the difference between them using the prop revolutions: 10 wheel revs will either produce 35 or 47 prop revs.  Only if you jack up the whole axle and spin both wheels.  If you just jack and spin one wheel, expect half that number of prop revolutions. Quote Link to comment Share on other sites More sharing options...
BogMonster Posted April 19, 2017 Share Posted April 19, 2017 On 18/04/2017 at 1:11 PM, Snagger said: Only if you jack up the whole axle and spin both wheels.  If you just jack and spin one wheel, expect half that number of prop revolutions. Think he probably fixed it or chucked it by now Quote Link to comment Share on other sites More sharing options...
Snagger Posted April 20, 2017 Share Posted April 20, 2017 Yeah, I saw the date after replying, but I thought I'd leave it as someone had resurrected the thread and it may have been relevant for anyone with the same question. Quote Link to comment Share on other sites More sharing options...
crewcab 110 Posted February 25, 2019 Share Posted February 25, 2019 guys can anyone help me i have a 1998 110 defender previously was a army v8 i have left the front axel in but a 300 tdi disco engine box and rear axel into it as it was on drums at the back ,its been getting built for some years took it for a spin around the block and it just dont seem rite i cant get it to pull away ive got to rev the nuts off it to get it to go and i am thinking the front diff could be an issue with it being off a v8 petrol i read on this post they are different could one of you landy chaps help me out as i am stumped. cheers Quote Link to comment Share on other sites More sharing options...
western Posted February 25, 2019 Share Posted February 25, 2019 ALL 90/110/RRC/Discovery 1 use the same diff ratio of 3.54:1 a ex military may have the lower 1.66:1 high range transfer box gear instead of the more common 1.410:1 gearing. Quote Link to comment Share on other sites More sharing options...
landroversforever Posted February 25, 2019 Share Posted February 25, 2019 4 hours ago, crewcab 110 said: guys can anyone help me i have a 1998 110 defender previously was a army v8 i have left the front axel in but a 300 tdi disco engine box and rear axel into it as it was on drums at the back ,its been getting built for some years took it for a spin around the block and it just dont seem rite i cant get it to pull away ive got to rev the nuts off it to get it to go and i am thinking the front diff could be an issue with it being off a v8 petrol i read on this post they are different could one of you landy chaps help me out as i am stumped. cheers Manual or auto? Quote Link to comment Share on other sites More sharing options...
western Posted February 25, 2019 Share Posted February 25, 2019 Won't be a auto if ex military. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted February 25, 2019 Share Posted February 25, 2019 @crewcab 110 said he'd put a Disco 300 engine + box in, if he swapped the transfer box as well that would make it 1.2:1 ratio where the original would be 1.4:1 so a bit more lively off the mark (well, a fair bit more lively with a V8 too), if it's pulling bigger tyres than a Disco (and most Defenders are) that won't help either. That said, a 300TDi in a 90 should be able to get out of its own way. I'm not so sure about his claim to have put a Disco axle under the back of a 110 as the 110 should have a Salisbury back axle, a Disco one isn't rated for the weight and surely the propshaft wouldn't meet up due to the diff pinion length difference there's something odd here. 1 Quote Link to comment Share on other sites More sharing options...
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