Help i have Bad Vibrations

[Mark01]

Hi All,
I have got into a bit of a state with my truck, hopefully some might be able to shine a bit of light on where to go next.

It all began a couple of weeks ago when whilst driving between 50-60mph I could feel a small vibration that you could drive through if you went faster also it would go if you let the power off.
Last weekend I picked up a new digger from Hereford with the truck, with the weight on it seemed to amplify the vibration, still not shaking the truck apart but it was there.

So in the week I looked underneath thinking I had a uj on the way out, all I could find was a small amount of play in the front uj of the front prop. I got 2 uj`s in thinking I will change both anyway then that's another job beat.
Changed them out on Saturday no problem. Went out yesterday to find the vibration still there and then got really bad and bang
The rear uj on the front prop decided to un attach itself from the truck. I managed to limp home as all this happened a few miles from home.
When I took the prop off again it looks like I lost a cap and the uj fell apart.
So question 1 is what went wrong here as I have not had this happen before.
I have driven the car into work this morning with the centre diff on and I still have a vibration now happening worse and at all speeds even when I lift off the power.
So question 2 where do I go from here. there is loads of backlash in the transmission but doesn't seem to be any play anywhere else ie rear prop seems fine and the front of the transfer box seems tight apart from the backlash- same with the front diff.
As this is my daily driver I am wondering if anyone might be able to suggest what to do first to find the fault or should I start refurbing diffs and gearboxes hoping to eliminate the problem.
I am a bit stuck with where to turn first at the moment.

Cheers, Mark

 

[stumog]

thats not good at all. I had some bad vibs on mine when i put i 2" lift on it and that turned out to be the front wheels out of balance but it didnt show up when at standard height. Its a cheap fix to make sure.

if not you can measure the back lash with a dial gauge to see if they are in spec before you start rebuilding everything. what is the state of the rear prop ujs?
stu

 

[frank rabbets]

Weight on the truck might be the clue. The rear prop will be running at a different angle than without weight on. This might cause a change in the vibration if it's the rear prop. I think front and rear UJ's on the rear prop may solve it. Try just doing the rear without fitting the front yet. Then do the front prop again which should be OK if not damaged. In my experience years ago play did not cause vibrations but seized UJ's did. Obviously you can't really tell UJ condition until the prop is off. Never had a LC UJ problem. Did you know you have to grease them every 4500 miles? Have you greased them every 4500 miles? I don't think the UJ cup flying out points to a fault other than not fitting correctly.

If there is no up/down play in the 4 drive flanges on the car I don't think it's the box or difs.

 

[frank rabbets]

P.S.

Another clue ? Your rear prop is now taking all the drive so may now be vibrating worse.

 

[AndycruiserguyLomas]

I may be wrong in my thinking but to my mind the angle of deflection of the prop will be reduced in the conditions shown in the photo so the symptms should be reduced.

Andy

 

[ajnabi]

... I back the theory about seized UJ's not showing play but causing vibrations and also what seems like backlash. Could also check rear brake shoes.


IQ

 

[AndycruiserguyLomas]

Yep, poorly maintained U/J's favourite in my book too.
Either that or some dodgy after market shocks

Andy

 

[Jon Wildsmith]

I have seen that kind of failure before when the circlips were not fully seated. You need to check them very carefully to be sure. I would check the rear prop UJ's first looking for the vibration - take it off, you can't check the UJ's properly on the truck.

 

[Mark01]

Hi All,
Thanks for the tips, after going home from work last night the truck did start squeaking when you pull away so I pulled the rear prop off and did indeed find the rear uj had been seized and was now well worn.
You can see the rust in the second photo.
I guess when I checked underneath last week I had a brain fart and thought all would be well with no slack in them.
I have ordered all new uj`s and will triple check the circlips are in good and tight then all should be well.
I haven't measured the backlash yet but is it correct to have more play in the front diff than the rear?

Andy I did wonder if was the dodgy goods I was buying but the ride is too good now.

Frank 4500 miles you say maybe I had one too many zero`s and thought they needed doing every 45000.


Once again thanks for the tips guys. I will check the backlash tonight and see what we have there considering the truck is up at 318000 miles now.

Cheers, Mark

 

[frank rabbets]

There is usually more play in the front flange because when you turn it it takes up play in the other parts of the front axle which the rear axle does not have. If you turn the front flange lightly you can just feel the backlash between the pinion and crown wheel before you have to turn the flange a bit harder to take the other play up.

 

[clivehorridge]

I like that Mark, every 45,000 ...... whether it needs it or not!

I'm sure you've cracked this vibration problem now. A process of elimination, starting in the right place thanks to the experience of the members. I have to admit, I'd have started with wheel balancing, and worked my way back to the prop shafts. It just goes to show....

 

[frank rabbets]

45,000 miles or 5 years whichever is the latest

 

[Mark01]

I don't understand it really,im normally quite stringent on servicing. I go berserk with a grease gun at the start of haymaking every year on all the machinery in the yard.

Cheers, Mark

 

[karl webster]

I had the exact same thing before Lincomb last year Mark.
Truck was completely fine though. I went and picked my trailer up and loaded my green lane cruiser onto the trailer. Set off got to around 40mph then the truck started to shake itself to bits. I sxxt myself. I'd never had anything like it. Turned out it was the uj on the rear prop. Chucked a different prop on and het presto.

 

[jonnyboy54321]

Sounds like I need to look at mine then, she's a bit of a shaker. Also got a problem with power application and trailing throttle - a decent clunk - as if the whole driveline is loose

 

[Bat21]

.... I go berserk with a grease gun....

Don't be going too berserk while pumping the slip joints.... 3 pumps is plenty

 

[stumog]

Don't be going too berserk while pumping the slip joints.... 3 pumps is plenty

Thats what you have been doing wrong all these years more pumps makes her happier!!
stu

 

[frank rabbets]

The problem is the care with which they are greased rather than the interval. The first few pumps force grease past the seals and you think ah that UJ's done. But probably there is one of the 4 joints on the spider where the grease has not come through. With mine I keep pumping until the stubborn one is passing grease. These stubborn ones are the ones which eventually go dry and look like a red egg timer when you take them apart.

 

[MuckyPup]

Quick little tip, the next time you do a few miles and you're wearing your scruffs get underneath and feel the temp of the UJ's (The posh amongst us will use a temp gun)
Cool, warm and even quite hot are to be expected.
The one you leave your fingertips behind on is on it's way out.........

On greasable UJ's you pump them full until ALL FOUR bearings show clean grease

 

[Chris]

If I don't get grease coming out of all 4 joints. I pull the prop and do it on the bench. Wiggling the flange around (ooer) tends to encourage the passage of grease through the bearing.