wobbly gearknob

[CAR]

Sadly a collapsed gearbox mount usually causes the U/J at that end of the prop to have a harder time and quite often fail. The fact that the vibration seems worse on the overrun would point to a failed U/J for me.

Colin.

[rustjunkie]

Right then .
Following a enforced lay up I have now fixed the wobbly gear leaver as part of a comprehensive rebuild
with the following. Re-con engine less than 500 miles when i got hold of it ,new engine mounts ,new gearbox mount and cross-member bushes ,new rear subframe arm bushes new front shock inserts and bottom ball joints.And as previously mentioned a re-con prop from cw but after all this the vibration I was suffering from is still present. Its visible in the interior mirror although less prevalent than it was. With car in bits there was a bit of backlash in the diff. Hard to say but just less than 1/4 inch.Much to much I know but
Would this cause the problem. Although there is no unpleasant noise and the nose of the diff has no play ?
a good second hand diff is on the way from Andy Harrison, got to pop over and pick it up.
The driveshafts where also removed and show no play in the UJ S or splines .Is it possible that they can go out of balance.
My thinking was that they are to short for this to be a problem? And finally with the new mounts and now correct number of spacers under the drivers side eng mount .2.5s engine and correct front plate. The gear box as viewed through the hole in car for gear leaver is over to the passenger side I.E. not central to car to the extent that the bayonet fitting on lever almost but not quite touches the tunnel . any help gratefully received ,as its very close to been found in a ditch on fire !!

[JimB]

One other thing to check is the quill shaft bearing. If oil leaks out the front if the diff, it can wash out any grease in the subframe nose piece, thus leading to bearing wear.

Is the vibration you're seeing in the rear view mirror horizontal, vertical or radial?

[wild bill]

This is going to sound odd,if you have a viscous fan,drop the fan belt off and try the car again!
Good Luck!

[tony]

One other thing to check is the quill shaft bearing. If oil leaks out the front if the diff, it can wash out any grease in the subframe nose piece, thus leading to bearing wear.

Is the vibration you're seeing in the rear view mirror horizontal, vertical or radial?

Had a similar vibration a few years ago. Before I got round to having a look. the flange on the end of the quill shaft broke off effectively stopping drive and draining the diff oil on the road. A bit hard to see if it's cracked without removing diff though.
I now reinforce this area with gussets welded in.
Tony.

[David Withers]

... The fact that the vibration seems worse on the overrun would point to a failed U/J for me.

Colin.

An out-of-balance rear wheel can be another source of vibration on the overrun. Swapping the wheels between front and rear might confirm or eliminate it as a cause.

I once had a quite severe vibration set in on the overrun about 15 miles into a long journey in the BMW I used to run. I thought it too risky to carry on, so I turned round and headed back home. Standing by the car and scratching my head as to what might be the cause, I spotted a bright spot on a rear wheel where a balance weight had come off. I happened to have some old balance weights in my scrap box, and fitting one that looked about the right size cured the vibration.

On another point... Recently balanced 'S' alloy wheels can't always be relied upon to actually be in balance. They can be difficult to balance precisely, especially - in my view - if the modern-type balancer is used. This type has a taper spindle on which the wheel sits, and a quick-action clamp that presses against the wheel to hold it tight on the spindle. The clamp typically goes inside the recess in the wheel where it presses against the raised letters cast therein. This can cause uneven clamping, leading to a slight run-out of the wheel as it is spun. Some (most?) balancers have an adaptor against which the wheel sits, i.e. the wheel is clamped face-to-face just as it is when on the car itself, but using the adaptor is not popular with operators as it's more of a hassle.

[Steve G]

I had similar problems with my car and it turned out to be the propshaft was the problem. It was a reconditioned one but didn't run true. Various check were made and I ended up taking it to a propshaft repairer and he said it nearly broke his balancer when he tried it !
The only way to fix it was to cut the yoke off and re-weld it. It was then balanced and was fine afterwards.

My method of checking it was to block the car up so the wheels were off the ground and then start the engine. Obviously you can't be careful enough when doing this and it isn't wise to get under the car while looking. I found that without putting the car in gear there was enough drag in the gearbox to spin the propshaft and one back wheel, it might be nesassary to put the car in gear but again be very careful. With the rear suspension fully extended the driveshafts make a pretty horrible noise with no load on them so not running the car for too long is probably a good idea.
The propshaft was running out of true but the ends were fine.

[johnconradlee]

I've found there is some variation in propshafts, so it could be you've got a duff one. Not that I've had any problems as severe as your's, but I have found in a couple of cars (when swapping to one out of the spares pile) that the "blue" propshaft seems to be quieter and better balanced than the others, hence, since it's now made its way out of the spares pile and on to LuLU, I plan on always refitting it.

[Steve G]

I don't think a faulty one would be a common thing mine muct have just slipped through the net, and , it was over ten years ago now !

I first thought it was the sliding joint as pumping it full of fresh grease improved things a lot. After finding the problem I think it was just damping the vibration.

I had problems with the wheel bearings and driveshafts and ended up with Datsun ones after trying and returning a set of the then new driveshafts with CV joints. The shafts were fine it was just the wheel bearings that were either set up wrong or were just poor quality. Again it was a long time ago now so things will have changed.

Hope the problems gets sorted out though.

[rustjunkie]

wow you lot are quick.
In relation to the fan ,a viscous one was fitted to the engine and was changed over to a solid mount type when the engine was fitted as it had a bit of rock in it and have heard that they can go into the radiator when they let go so thought if prudent to swap it over .The vibration in the mirror is more of a radial one and is there almost from walking speed but can,t be felt in the car till about 50 mph and then its only slight but the mirror vibrates to the extent that its imposable to read the reg of a car behind or tell the make.I will have a look at the diff quill shaft tomorrow it is leaking oil from behind the flange but hope to fit good diff in to car next week.will also get the wheels balanced, tyre fitter local to me in Crediton is a good one but I do remember from last time they had a lot of weights added to inside maybe time to put stag steels on it if I can get some . will report my findings next week. Thanks for the help so far. I think will get there in the end probably missing something blindingly obvious