Disco_Dunk Posted April 7, 2006 Share Posted April 7, 2006 Hi Guys........ I've got an ex-RAC N-reg (300tdi) Disco, and it's been developing a drivetrain vibration at about 65mph and above. I'd noticed that the vibration disappears as soon as I let my foot off the accelerator (even when still running over 65). My first thought was rear prop UJ, so I whipped the prop off and swapped the UJ, but no joy. HOWEVER...... when removing the propshaft, I noticed that the rubber 'do-nut' is really slack (for want of a better description) - I can waggle the do-nut about all over the shop, and it's not the donut itself that's loose, it's the whole flange assembly. So, now I'm guessing that the 'front' bearings in the diff are shot, which is probably backed up by the oil that's leaking from the diff!....... does that sound like a fair assumption? If it IS the case, am I looking at a full diff re-build, or is it relatively straightforward to replace the bearings?....... to be honest I'll be inclined to replace the diff with a recon unit, rather than re-build it!! Cheers Dunk Quote Link to comment Share on other sites More sharing options...
onions Posted April 7, 2006 Share Posted April 7, 2006 Is the donut visibly deteriorating by any chance? Does it look like it's ever been replaced? The reason I ask is that my 98 Disco sounded similar to yours, until one day the donut disitergrated on a slip road and destroyed the rear diff as it went. Had the donut been replaced then the dodgy bloke who flogged me the car would have had me offloading it onto his forecourt on a Sunday morning. Anyhow. Someone who knows more than me will be along soonish. Quote Link to comment Share on other sites More sharing options...
Phil Hancock Posted April 7, 2006 Share Posted April 7, 2006 Hi Guys........ I've got an ex-RAC N-reg (300tdi) Disco, and it's been developing a drivetrain vibration at about 65mph and above. I'd noticed that the vibration disappears as soon as I let my foot off the accelerator (even when still running over 65).My first thought was rear prop UJ, so I whipped the prop off and swapped the UJ, but no joy. HOWEVER...... when removing the propshaft, I noticed that the rubber 'do-nut' is really slack (for want of a better description) - I can waggle the do-nut about all over the shop, and it's not the donut itself that's loose, it's the whole flange assembly. So, now I'm guessing that the 'front' bearings in the diff are shot, which is probably backed up by the oil that's leaking from the diff!....... does that sound like a fair assumption? If it IS the case, am I looking at a full diff re-build, or is it relatively straightforward to replace the bearings?....... to be honest I'll be inclined to replace the diff with a recon unit, rather than re-build it!! Cheers Dunk If as you say the flange is able to be moved in any direction other than rotary & you dont know what you are doing with it repair wise then get a rebuilt unit as running with that much play will have done some damage to the crown wheel & pinion. Quote Link to comment Share on other sites More sharing options...
BogMonster Posted April 7, 2006 Share Posted April 7, 2006 What Phil said ^^^ If it is "really slack" then get it done ASAP or there may be an expensive bang followed by a hedge, in that order! Quote Link to comment Share on other sites More sharing options...
Disco_Dunk Posted April 7, 2006 Author Share Posted April 7, 2006 Thanks guys.....sounds like a recon diff on order then!!...... is there an easy way to sort out if I need a 10-spline or 24-spline diff - do both ends of the half-shaft have the same number of splines, or do I have to pull the shaft completely to check the inner end? Ta Dunk What Phil said ^^^If it is "really slack" then get it done ASAP or there may be an expensive bang followed by a hedge, in that order! Quote Link to comment Share on other sites More sharing options...
toger Posted April 7, 2006 Share Posted April 7, 2006 Does it have a suspension lift by any chance? Quote Link to comment Share on other sites More sharing options...
BogMonster Posted April 7, 2006 Share Posted April 7, 2006 I am 99.9% sure a 300Tdi Disco will be 24 spline, I think all Discoverys are 24 spline but sure that 300s are. You shouldn't find any splines on the outside end as the shaft should be one piece with the drive member Quote Link to comment Share on other sites More sharing options...
white90 Posted April 7, 2006 Share Posted April 7, 2006 early Discos have 10spline same as the RR classics had with 2 piece CV's large mushroom headed drive members a 300 will be 24spline and have 1 piece rear halfshafts with the slim mushroom head as fitted to the 300 Defender Quote Link to comment Share on other sites More sharing options...
Disco_Dunk Posted April 8, 2006 Author Share Posted April 8, 2006 Thanks for clearing up the splines fellas - 24 it is then! Anyone got a spare they wanna get rid of?? Dunk (PS - no lift kit fitted, but I'm guessing as it's an ex-recovery motor it's probably worked hard, though not off-road) early Discos have 10spline same as the RR classics had with 2 piece CV's large mushroom headed drive membersa 300 will be 24spline and have 1 piece rear halfshafts with the slim mushroom head as fitted to the 300 Defender Quote Link to comment Share on other sites More sharing options...
BogMonster Posted April 8, 2006 Share Posted April 8, 2006 No - because both my 90 and my Discovery sound like they need new back diffs too! Quote Link to comment Share on other sites More sharing options...
Phil Hancock Posted April 8, 2006 Share Posted April 8, 2006 Thanks for clearing up the splines fellas - 24 it is then! Anyone got a spare they wanna get rid of?? Dunk (PS - no lift kit fitted, but I'm guessing as it's an ex-recovery motor it's probably worked hard, though not off-road) Late 200tdi had the thin 24 spline flanges on the front with the flat rear shafts but they were still 10 spline in the diffs. So 200tdi = 10 spl & 300tdi = 24spl Quote Link to comment Share on other sites More sharing options...
white90 Posted April 9, 2006 Share Posted April 9, 2006 I've fitted a late 200TDI axle with the thin halfshafts ends and that was 24spline I haven't seen thin one piece halfshafts that are 10spline personally. Quote Link to comment Share on other sites More sharing options...
Phil Hancock Posted April 9, 2006 Share Posted April 9, 2006 I've fitted a late 200TDI axle with the thin halfshafts ends and that was 24splineI haven't seen thin one piece halfshafts that are 10spline personally. Ive got a pair of thin flange 10 spline axles. The fronts are 24 spline in the flange but 10 in the diff. The rears externally look the same as the 24 spline variant but are definitely 10 spline in the diff. Quote Link to comment Share on other sites More sharing options...
white90 Posted April 9, 2006 Share Posted April 9, 2006 Bluddy L/R nothing ever easy Quote Link to comment Share on other sites More sharing options...
Phil Hancock Posted April 10, 2006 Share Posted April 10, 2006 Bluddy L/R nothing ever easy Hear hear!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Quote Link to comment Share on other sites More sharing options...
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