Video of P38 vibration at idle what are your thoughts

Littelwill said:

James is close by that's true. I'll have another crawl under it this morning thanks for your help Grrr appreciate it.

Click to expand...

You're welcome but I think it could do with someone who isn't guessing.

I'm intrigued by the fact it doesn't do it when the gearbox is in neutral but does do it in park or any gear. I'd have thought an autobox would dampen vibrations from the engine side. What's the difference between park and neutral?

A quick Google seems to imply the only difference between N and P is that the output shaft is locked by a pin in P. Is that true for the P38?

If so, I'm confused. Neutral should uncouple the input and output shafts from the gearbox, right? And if in park the output shaft is pinned as well then how could vibration get downstream to be heard in the transfer box? Unless the locking mechanism itself was coupling the front and back of the gearbox again.

Assuming the output shaft is locked in P then I struggle to see how anything can be turning in that transfer box so it must be referred noise.

Being as the noise disappears on moving the vehicle I'd being looking at things like external fittings.

By pushing on the transfer case you may take the pressure slightly off a tight item or even adding that bit of extra vibration dampening that stops the noise, have you looked at the gear selector lever + the Hi/Lo shift under the centre console, is the cable rubbing the body. Is the engine running at the correct idle speed.

My diesel has a habit of at times idling at 800 rpm a quick tap on the throttle the idle drops to just under 750 rpm, I presume its the throttle pot or the throttle control for the engine sticking, also between 60 mph and 68 mph the gear lever rattles a bit, just drive at 70.

As we all know noises like these can be caused by anything, good luck, it is generally something silly and an easy fix but finding the cause, now that something else.

I also don't think its inside the transfer case, I'd say its a cover rattling or something like that or as stated before could even be loose exhaust internals...

I guess you could unbolt the front of the centre section of the exhaust. After that it is just hanging by the rubbers so that would eliminate that from the mix.

Wish this bl**dy rain would stop!

Mine had exactly the same vibration and I sorted it by taking it to the local specialist and having the idle speed increased and replacing the gearbox mounts. The new mounts raised the transmission a clear half inch with the resulting vibration cured.

I can't understand it either Grrr. When you look at the way the whole system works nothing should move and there should be very little play in anything inside the transfer box. But this seems to be where it's coming from. Unless the vibration is happening upstream and flowing through to the transfers box which is the last point...

Rob Edge said:

Mine had exactly the same vibration and I sorted it by taking it to the local specialist and having the idle speed increased and replacing the gearbox mounts. The new mounts raised the transmission a clear half inch with the resulting vibration cured.

Click to expand...

What did you have your idle speed increased too? Mine idles at like 720 (which I believe is what it should) and your new mounts where they genuine or blue bag? Mines had both fitted and still got it...

Thought idle was 750?

I had a friend put it on nanocom and he said it was idling just fine between 720/50

Littelwill said:

What did you have your idle speed increased too? Mine idles at like 720 (which I believe is what it should) and your new mounts where they genuine or blue bag? Mines had both fitted and still got it...

Click to expand...

Idle set to 750 which on mine was increment 4 and the mounts where genuine LR.

Littelwill said:

I had a friend put it on nanocom and he said it was idling just fine between 720/50

Click to expand...

Sounds about right. Drops a bit when the air-con cuts in.

Littelwill said:

What did you have your idle speed increased too? Mine idles at like 720 (which I believe is what it should) and your new mounts where they genuine or blue bag? Mines had both fitted and still got it...

Click to expand...

Should be 750, although it also states +/- 50rpm. Mine idles at 800 on the dash, but Faultmate shows 750.

I see... Hmmm maybe I should invest in a nanocom so i can play around with it as and when. Feel bad having to keep bothering folk for help.

Mine idles with the needle slap on the second notch on the rev counter which is 750 rpm. It dips ever so slightly when the air-con cuts in. Nanocom mirrors the rev-counter readings.

I dont know lol.....