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ytt105
25th November 2009, 09:37 AM
1996 4.6, 180k P38a

When the revs get to between 3500 and 4000 there is a vibration from the driveline.

I checked the rear driveshaft and found that I could get a knock, in each direction, quite easily. But only one knock, and I couldn't see any movement.

However, I'm assuming this is enough to tell me I should replace all four unis and hopefully this is the vibration.

Are aftermarket unis OK, or should it be genuine only? Where do I get them?
p38arover
25th November 2009, 09:52 AM
Is it RPM related or driveline? What happens if you change gears to change RPM at that road speed?
ytt105
25th November 2009, 03:36 PM
Yes its RPM related, not road speed!

Don't tell me its the flex disc, that's not what I want hear!!

I'd rather change the unis!
Rangier Rover
25th November 2009, 03:43 PM
Yes its RPM related, not road speed!

Don't tell me its the flex disc, that's not what I want hear!!

I'd rather change the unis!

Flex plate is plausible.. I hope not for your sake.
My rangie developed a vibration at high RPM and turned out to be a spark plug breaking down. Took a wile to find it to I may add.;)
mike 90 RR
26th November 2009, 10:56 AM
If you hate the Flex plate theory ....
another couple to add to Rangier Rover's list .... Check the condition of the rubber engine mounts .... and the Harmonic balancer hasn't moved on it's rubber bushing ;)

Mike
:)
Hoges
27th November 2009, 11:20 AM
Quote: "Are aftermarket unis OK, or should it be genuine only? Where do I get them?"

I got some after market ones from Britparts UK for about $7 each...THEN I did some research and found that the special Hardy Spicer heavy duty version for the Defender also specified for the P38... varying in price from A$60-75 EACH :o:(. THEN I discovered the good folk at Land Rover Parts (http://www.lrparts.com.au/index.htm) and they were delivered to Bris for about $50 each. The difference in quality is readily apparent :D
ds23man
30th November 2009, 04:36 PM
Maybe your viscofan is on the way out! Can cause serious vibrations when you rev up.
mike 90 RR
30th November 2009, 08:06 PM
Maybe your viscofan is on the way out! Can cause serious vibrations when you rev up.

Not a bad call, actually ... :)

Check your plastic blades for splitting ....
Mike
ds23man
1st December 2009, 04:54 AM
It is very easy to check, take it of and rev your engine up!

Gerhard

PS If you see some progressing woble in the outer rim when you rev up, it is out!:(
ytt105
2nd December 2009, 09:40 AM
I've changed the fan and the viscous unit, there were a couple of small 'nicks.
It helped a little bit, but the vibration is still there. You really don't want to rev that high!
I'll have a look at the engine mounts and balancer this weekend.
Scouse
2nd December 2009, 10:13 AM
Pop the belt off & run it for a minute like that. It will eliminate all that runs off the belt that way.
mike 90 RR
3rd December 2009, 10:21 AM
Pop the belt off & run it for a minute like that. It will eliminate all that runs off the belt that way.

.... and Scouse really does mean, run the motor for NO LONGER than 60 seconds from cold ....

Mike
Scouse
3rd December 2009, 10:25 AM
If you can reproduce the vibration at any time, you'll know with the first rev anyway.
ds23man
19th February 2010, 03:41 AM
Did you solve the problem????

Regards,

Gerhard
ytt105
20th February 2010, 08:17 PM
The local Rangie expert in Canberra said its the crankshaft as some of the early ones were slightly out of balance from the factory.
Now i just drive through it, but i will be getting some new engine mounts soon.

That should help a little bit!