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#Post#: 97193--------------------------------------------------
VIBRATION AT 30-35MPH any ideas?
By: DARKSIDE Date: April 22, 2015, 4:05 am
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Morning
I have a 88 petrol series 3.
I have a vibration at 30-35 that is quite bad. Free wheeling
hubs so not front end driveline related.
Running new Michelin XZL tyres.
I have changed the diff for a good one. I have put a NEW rear
prop on. I have recently fitted an Ashcroft High Ratio transfer
box with all new bearings.
I still have the vibration. It happens power on, and on overrun.
Any ideas?
Could this be gearbox mounting rubbers?
#Post#: 97210--------------------------------------------------
Re: VIBRATION AT 30-35MPH any ideas?
By: blackskidmarks Date: April 22, 2015, 2:46 pm
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Did you replace the prop shaft to try to fix the vibration, or
has it only vibrated since fitting new prop?
Is prop assembled correctly? (even though new!) Needing grease?
Wheels balanced ok?
Is it a `complete car` vibration, or one `underneath` that you
can feel?
loose nuts on gearbox shafts?
#Post#: 97217--------------------------------------------------
Re: VIBRATION AT 30-35MPH any ideas?
By: DARKSIDE Date: April 23, 2015, 2:03 am
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I had the vibration before the new prop was fitted. I changed
the diff but it remained.
I have the tiniest bit of play in the handbrake drum.
I replaced the prop as the old one was a bit sloppy in the
sliding splines.
I am thinking maybe gearbox mounting rubbers or propshaft
phasing.
#Post#: 97221--------------------------------------------------
Re: VIBRATION AT 30-35MPH any ideas?
By: DarrenH Date: April 23, 2015, 4:35 am
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remove rear prop completely, engage free wheel hubs, engage
fourwheeldrive high, go round the block in front wheel drive?
might point you to which end of the truck you are dealing with
#Post#: 97225--------------------------------------------------
Re: VIBRATION AT 30-35MPH any ideas?
By: spitfiremk1uk Date: April 23, 2015, 7:07 am
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I hesitate to offer a reply with any suggestions simply because
it could be almost any rotating component(If it even is a
vibration!).
The trick is identifying the speed of the vibration and roughly
where it is coming from. Experience is often a huge factor in
identification. In my experience harshness is often mistaken for
a vibration, noises are missed and very often there are more
than one fault present and often ignored by long term drivers.
In this area, if you dont want to waste your time changing every
component just because someone suggest it on a forum experience
is everything. And if you have none its hard to learn quickly!
The only sure fire way is to drive the car and feel it for
myself.
Vibration or harshness? Low or high frequency? Drive, overun,
cruise? Feel it through the steering wheel or bum. Any noises?
Sorry if this hurts the ego, but why on earth did you change a
rear diff whilst looking for a vibration? Was the diff actually
faulty?
has the vibration been present from the moment the new transfer
box gears were installed? Were the output shaft bearing preload
adjusted properly?
The list really can go on and on. My advice is. Find yourself a
genuine old landrover mechanic and let him road test the car. It
really will save you so much time and wasted effort.
If you insist on trying to find it yourself you need to carry
out a decent road test and try every combination of gears,
speeds, engine loads, rear 4wheel and front wheel drive And lets
hope its a real vibration and its not just a harshness caused by
the wrong floor screw being fitted, as an example!!!
#Post#: 97228--------------------------------------------------
Re: VIBRATION AT 30-35MPH any ideas?
By: Serious Series Date: April 23, 2015, 8:47 am
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Are you detecting the play in handbrake drum via a dial gauge ?
If not your output shaft needs it's preload checking , just
tightening the output shaft nut might cure it but the circlip
can come off the front side of gears if over tightened.
#Post#: 97233--------------------------------------------------
Re: VIBRATION AT 30-35MPH any ideas?
By: DARKSIDE Date: April 23, 2015, 11:36 am
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Thanks for your replies..
[quote]why on earth did you change a rear diff whilst looking
for a vibration? Was the diff actually faulty?
[/quote]
The pinion bearings were rough on the one I took out, and the
one I replaced it with was a known good one.
I was running on SAGS before and I assumed the vibration was
down to these somewhat, indeed some of it was..
All the preloads were correct when I rebuilt the box, and I used
what I assumed were quality bearings.
[quote]If you insist on trying to find it yourself you need to
carry out a decent road test and try every combination of gears,
speeds, engine loads, rear 4wheel and front wheel drive And lets
hope its a real vibration and its not just a harshness caused by
the wrong floor screw being fitted, as an example!!![/quote]
In fairness I have tried most things before asking on these
forums, I am just a bit stumped.
[quote] Find yourself a genuine old landrover mechanic [quote]
I am in my 31st year of owning old Land Rovers, and my dad ran
them before me. I think I need to find a genuine new landrover
mechanic.. :)
#Post#: 97234--------------------------------------------------
Re: VIBRATION AT 30-35MPH any ideas?
By: spitfiremk1uk Date: April 23, 2015, 12:13 pm
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So is it a vibration or harshness?
Wheel speed or prop speed?
Engine load related?
Does engaging 4 wheel drive change things?
Does removing the rear prop and running front wheel drive only
change things?
Have you got the vibration then disengaged drive and coasted in
nuetral? What does this do?
Just a short list of ToDo things. That need to be done before
swapping any components. After this you will have found where
the vibration is coming from and you can start to chase it down.
As far as experience goes. There are many drivers. Most of these
drivers use their landy as a second or third car and actually
travel limited mileage.
An old landrover mechanic will have driven an old landrover
nearly every day of his working life. He is able to compare your
car with known good cars. He has chased down your problem
before. Because frankly there is not much to go wrong and he has
been doing it a long time.
I have drivers of landies in my area who refuse to take their
car to a real mechanic because a landy is "simple". Fair enough.
But I wouldnt trust these same guys to adjust a wheel bearing
properly, set up a diff or rebuild a gearbox. So you must excuse
my scepticism towards what drivers call experience when it comes
to actually fixing a car, problem solve and logicaly discount
irrelevancies and cant tell whether something is "vibrating" at
wheel speed or prop speed.
And if logic cant sort it out you have to rely on a mechanics
personal experience to identify "vibration".
Let me know if you know how I can in any way explain how to
describe vibration, harshness and the "feel" of your car to you
and others.
#Post#: 97348--------------------------------------------------
Re: VIBRATION AT 30-35MPH any ideas?
By: DARKSIDE Date: April 30, 2015, 2:39 am
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I think my problem may be from the parabolics..
Diff is slightly nose up, so the output flanges on the diff and
gearbox aren't parallel.
I am going to try some wedges to try and get the nose
horizontal.
Have a look at this..
HTML https://www.youtube.com/watch?v=gmV4qwLfOMY
#Post#: 97416--------------------------------------------------
Re: VIBRATION AT 30-35MPH any ideas?
By: Dirty Girty Date: May 5, 2015, 9:56 am
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Now that is a cracking video.....never realised this. Must admit
I could not find the alignment arrows on my drive shaft when I
split it to replace the UJ's. So I centre punched a couple of
dots to ensure I maintained the alignment upon re assembly.
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