Slightly concerning rumble...

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BigJock2005

Active Member
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308
Location
Bucks
Went out to test the '99 P38 4.6HSE at high speed since doing me spring kit. She went perfect except a new noise has appeared. I don't know if I've buggered something doing the springs or not.

Basically when I lift of the throttle, so that the motors s neither driving or braking, I get this rumble. Sounds like the noise you get if you've fitted tyres that are too nobbly. Defo coming from the front. Touch the throttle, or lift off at all, and it disappears.

Searching the forum I'm seeing things like prop shafts and transfer boxes... She's not leaking any oil - honestly, she never has either.

Anyone got an idea? Could I have knacked a prop shaft when I dopped the front axle?

Cheers
Jock
 
is it vibrating at all? i had a rumble and vibration from the front of mine but only when you had the throttle down, turned out to be the front prop and uj. Had a new uj and the prop was rebalanced. Not exactly the same problem as your but might help you find the answer!!
 
Jock, in some cases when fitting coil springs you get a bit more road noise being transmitted through the chassis - it may just be this
However, if I remember correctly you have fitted heavy duty +2" springs
This will have changed the prop shaft angle and probably put a different strain on the radius arm bushes - check these and the u/j's have absolutely no play in them
Telt ye tae stick wi standard length springs ! :rolleyes:
 
No-one can tell me anything...I have to arse it up for myself. Think you're right about the road noise, the springs transfer a bit more being solid metal, but I have a good ear for motors and would've noticed this even a lot quieter than it is.

I'll climb under again and check the prop shaft and u/js. What's the most obvious sign of knackeredness? Should there be much play in them?
 
there should,nt be any play in them,might getaway with a very tiny bit of deflection,but it should be so small you shouldn,t be able to see it
 
As Andy says there should be no play - it's sometimes hard to check with the propshaft in place - try a pry bar between the yokes and GENTLY put pressure on to look for movement
If you suspect them get it off and into a vice to have a proper look
I never noticed any real difference in road noise when I changed mine, but I do run a fairly aggressive all terrain tyre that aren't that quiet anyway
 
Last edited:
Even if your UJs are OK, a 2" lift can cause the yokes to bind, causing exactly the symptoms described.
The cure is to fit wide yoke prop(s) or go back to standard height.
 
Don't think it was a 2" lift - maybe 1.5 max, cos it's not much higher than I remember it in high mode... will have to measure up to be sure. I can tell you, going to back to standard high is off. Those bastards aint ever coming out again.

But, even if the lift was straining the UJs why would it only make that noise on no-load? It would complain under load or engine braking no?

I'm gonna get under there with a grease gun and pump grease into everything. Then I'll fit nobbly tyres and uprate the blaupunkt. When it's so noisy the kids complain then I'll do something about it.
 
Treworgey 90 said:
Even if your UJs are OK, a 2" lift can cause the yokes to bind, causing exactly the symptoms described.
The cure is to fit wide yoke prop(s) or go back to standard height.
Click to expand...

Right lads. Climbed under and checked UJs and shaft. Totally no play in joints at all that I could feel, and surprisingly little play through the transfer box too. All felt pretty tight for an 83k motor to me. I *did* notice a clean patch on the sliding joint though, as if it's extended a 1/2" further that previously.... Packed the UJs with plenty of moly grease, but rumble didn't change and is really pretty noticable at speed when I let off the gas.

I am not reducing the ride height, so I am looking at a front prop shaft at least - can't hear any noise from the back.

Any tips on where I can find a wider angle P38 propshaft? I've asked the guys at Devon 4x4 who've asked me to measure it up, send a photo and they'll do me a quote.

Does anyone know - would I fit Disco2 shafts fit? Seem to have the same flange arrangements.

Jock
 
I get similar noise but when lifting off at any speed above 40mph the sound lasts for a couple seconds max then goes away, i also get a judder between 15 and 20mph which felt like ujs but mine are all new as is front prop, on speaking to my friend he recons tracking is out and steering dampner could do with being renewed as it takes a bit of correcting some times. The noise could be tyres? I run goodyear wrangeler 255 55 19 on 06 range rover wheels with spigot wrings, my standard 18 inch wheels did the same with the same tyres?
 
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