Cruez Posted June 4, 2003 Share Posted June 4, 2003 This isnt exactly a hybrid post but I bought a '86 4x4 Nissan PU over the weekend for cheap.. my other one died on me I noticed when you start off or when you have your foot into the gas there is a lot of vibration, I mean a lot... While normal driving seems to be fine... Its when you put the torque to it when it acts this way... I looked at the shafts.... pushed a little on the tranny mount but I don't see anything unusally loose. Is there something I'm overlooking?? Quote Link to comment Share on other sites More sharing options...
Guest greimann Posted June 4, 2003 Share Posted June 4, 2003 The differential is winding up under heavy load, changing the pinion angle relative to the driveshaft and causing a phase vibration. OR, If you have a two piece driveshaft, the intermediate bearing is worn out. Quote Link to comment Share on other sites More sharing options...
Cruez Posted June 4, 2003 Author Share Posted June 4, 2003 There are acutally three shafts.. (4x4)... but the differential answer could be a possibility.... The vibration is so bad the whole truck shakes with the tranny moving quite a bit also.. I'll have to take a look at the diff mounts.... I didn't even think of that.. The truck has a lift kit on it... (except the front , they just turned up the torsion bars)... I am assuming that would have some effects to it as well... right? If it was not done correctly? Quote Link to comment Share on other sites More sharing options...
Cruez Posted June 5, 2003 Author Share Posted June 5, 2003 oops... no diff mounts... never worked on a truck Anyway... there seems to be no slack in any of the drivetrain...I rocked it back and forth to see if I saw anything abnormal... nothing.. What else could it be... I'm baffled... Quote Link to comment Share on other sites More sharing options...
David K Posted June 5, 2003 Share Posted June 5, 2003 Is the truck a manual or an automatic? If its a manual, then it could be your clutch rubbing on an uneven flywheel. Quote Link to comment Share on other sites More sharing options...
zxgts-4 Posted June 5, 2003 Share Posted June 5, 2003 I would have gone for the centre tailshaft rubber mounting too. It seems too obvious but you aren,t getting a bad missfire under load ie; bad plug lead or cap, hard to diagnose from Australia without more info. Neil Quote Link to comment Share on other sites More sharing options...
Cruez Posted June 5, 2003 Author Share Posted June 5, 2003 Its a manual, but... It will do it even after its fully engaged.. No misfires now, I just tuned it up tuesday. Center tailshaft mounting rubber... hmmm what part is that exactly.. There are 3 shafts... the one from the transfer case to the front diff.. the rear (main) driveshaft and the small one between the tranny and the transfer case.... I know on my other truck it had a mount midway between the driveshaft as some sort of carrier... but tis one does not. Is it possible there is an internal problem with the rear diff? If so what do I need to look at if I pull off the cover.. Maybe I need someone to drive it while I hang my head under the truck Quote Link to comment Share on other sites More sharing options...
jt1 Posted June 5, 2003 Share Posted June 5, 2003 How much lift? Too much can get the driveshaft angle's so sharp that it vibrates under load. I don't know how much is too much though. I do know some of my 4x4 buddies have a lot of trouble with this. John Quote Link to comment Share on other sites More sharing options...
zxgts-4 Posted June 5, 2003 Share Posted June 5, 2003 yeah I was thinking it had 2 piece tailshaft like my 4x2. Next option is to disconnect rear tailshaft from diff - marking flanges first so can re-align after-and check that unis move freely, not binding or sloppy. Otherwise JT1 could be right, lift is too high and you need to fit wedges between diff and springs to raise the nose of diff to reduce angle at uni. neil. Quote Link to comment Share on other sites More sharing options...
Cruez Posted June 5, 2003 Author Share Posted June 5, 2003 The steel blocks that are in there are about 3 inches tall... I plan on taking them out and lowering the front by the torsion bars anyway...( front has some wicked camber) and get it back to stock height. Maybe that will fix it... Before I mess with the torsion bars, if I take out the bolts on the threaded rods... is it going to spring out with violent force?. Quote Link to comment Share on other sites More sharing options...
zxgts-4 Posted June 6, 2003 Share Posted June 6, 2003 If you have got the spanners out I would still check uni's on tailshaft. Yes even with the suspension hanging there will still be tension on the torsion bars, but you should be able to reset adjustment in this position.Note lube adjustment bolt before you start. If you want to undo any of the mounting points you will need to separate one of the balljoints so the lower control arm can hang further. Have fun! Neil Quote Link to comment Share on other sites More sharing options...
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