Snagger Posted October 15, 2008 Share Posted October 15, 2008 Hi folks. My '95 RRC (300Tdi) develops a mild rumble and vibration at the front end at about 68 mph with medium toque loads applied. If the throttle is backed off or pushed all the way to the floor, the vibration stops, and the speed band for the vibration is only 2-3mph either side once it has started. The CV joints in the swivels have been replaced (the left one had failed), as have both UJs in the front prop. The rear prop's rotorflex and bush are new, though the UJ did not need replacement. Fitting the new UJs in the front prop temporarily reduced the vibration but did not eliminate it. I now suspect a worn slip joint or unbalanced prop, but don't want to be replacing good parts on wild guesses. Does anyone have any other ideas, please? Quote Link to comment Share on other sites More sharing options...
bishbosh Posted October 15, 2008 Share Posted October 15, 2008 Take the front prop off, slip it into diff lock and go for a (gentle) drive. If your problem has gone away then it is either the prop or the front diff. Personally I would suspect the prop, although most often props tend to rumble on over run rather than steady load. How is the output flange bearing on the T case? Quote Link to comment Share on other sites More sharing options...
Snagger Posted October 15, 2008 Author Share Posted October 15, 2008 Unfortunately, I can't remove the prop and go for a test run as these Classics have the viscous unit, not the standard centre diff. The bearings seem fine, though. I wonder if upgrading to a TD5 Discovery prop (with the yolks swapped over if they differ) would help? Quote Link to comment Share on other sites More sharing options...
Highway_Star Posted October 15, 2008 Share Posted October 15, 2008 When mine had similar sounding vibrations it was due to the sliding joint no longer sliding. Quote Link to comment Share on other sites More sharing options...
DEANO3528 Posted October 15, 2008 Share Posted October 15, 2008 Unfortunately, I can't remove the prop and go for a test run as these Classics have the viscous unit, not the standard centre diff. Err they will run fine with the front prop off. Both my mate and I have run several hundreds of miles with our Borg Warner T/Boxes only working the back end. his was manual and mine auto. No worries. Quote Link to comment Share on other sites More sharing options...
Snagger Posted October 15, 2008 Author Share Posted October 15, 2008 Err they will run fine with the front prop off. Both my mate and I have run several hundreds of miles with our Borg Warner T/Boxes only working the back end. his was manual and mine auto.No worries. OK - I rralise that they will run like that, I was just worried about damaging the viscous unit with it continually slipping. Quote Link to comment Share on other sites More sharing options...
landmannnn Posted October 15, 2008 Share Posted October 15, 2008 Do you get any wheel wobble at this speed as well? Is the suspension lifted? It might help with diagnosing the fault. Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted October 15, 2008 Share Posted October 15, 2008 Could be the wheel bearings - just push the wheels in and out. But I would put my money on the UJs first. Quote Link to comment Share on other sites More sharing options...
Snagger Posted October 16, 2008 Author Share Posted October 16, 2008 It's not the wheel bearings - I replaced them as a matter of course when I fit the new CV joints. The swivel pins are good too. The front suspension is entirely standard, apart from DeCarbon dampers. The rear has police springs (about 1/2" lift) , but the vibration seems very strongly to be from the front. The amount of vibration was cut by about 80% after replacing the UJs, though over the next couple of thousand miles a lot of it has come back. It's not bad, just irritating. Evertything seems to point at the prop, but I have a habit of replacing lots of expensive bits before finding a cheap and simple cure... Quote Link to comment Share on other sites More sharing options...
bobtail84 Posted October 16, 2008 Share Posted October 16, 2008 Check the pan hard rod bushes.... dont laugh, i spent the budget of a small country looking for a vibration and it was the panhard rod bushes. Get someone to move the steering wheel from side to side and have a close look at both ends. Jeff. Quote Link to comment Share on other sites More sharing options...
Snagger Posted October 17, 2008 Author Share Posted October 17, 2008 They were replaced at the same time as the rest of the bushes at about the same time as the CV joints, So the suspension should all be fine. Just to rule them out too, the worn tyres have been replaced with new and balanced since the UJs were done, with absolutely no effect. I think it's transmisson related, either in the prop or the axle. I'm just wondering if there's anything obvious on the axle to check, other than wheel bearings and swivel pins, as I can't find much play in the prop. Quote Link to comment Share on other sites More sharing options...
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