PDA

View Full Version : Drive Line pulsing noise


coolum
5th May 2022, 07:23 AM
Just wondering if anyone has an opinion on the following noise.

D3 V8 New auto box - new tyres - no difference to noise.

As you accelerate the low frequency pulsing sound develops, then as revolutions increase the pulsing turns to a constant and increasingly higher frequency (still pretty low though)

When you slip the transmission into neutral the car is quiet and the noise has gone - then back into gear and it returns.

Thanks in advance for any contributors.
BushDisco
5th May 2022, 09:16 AM
Rear prop shaft centre bearing?
coolum
5th May 2022, 12:27 PM
Sounds cheaper than a new diff (front or rear) or transfer case for that matter?? as it has 340K on clock - its only a matter of time for these to need a renno.
Eric SDV6SE
5th May 2022, 12:33 PM
At a steady road speed, does the engine rpm vary? If so it will be your torque converter lock up clutch slipping.

If rolling along in neutral and noise is gone, unlikely to be prop shaft centre bearing, uni joints or transfer case, as these are still spinning / free-wheeling with the wheels turning.

Sounds transmission related to me.
coolum
5th May 2022, 01:09 PM
I have not noticed any engine rev variation during rolling along.

I had a new transmission and Torque converter (new in crate - not reconditioned) installed 30K ago it is possible (but hopefully unlikely) to be the problem..

I have it booked into British Offroad on sunny coast at end of May to review and rectify if found.

It does concern me that when in neutral there is no 'whine' at any speed - perhaps it is the new tranny. Damn

Cheers
Eric SDV6SE
5th May 2022, 01:21 PM
Check the fluid levels. Not sure what box the D3V8 runs, for the D4V6 diesels running the ZF 6 spd, fluid should be dribbling out the fill hole with transmission at 35deg c and engine running to be correct.

A full fluid flush may help.
coolum
5th May 2022, 03:22 PM
Check the fluid levels. Not sure what box the D3V8 runs, for the D4V6 diesels running the ZF 6 spd, fluid should be dribbling out the fill hole with transmission at 35deg c and engine running to be correct.

A full fluid flush may help.

I will see what the British offroad guys diagnose and get it done.
Thanks Eric for your input.
Steve
timdo1
11th May 2022, 07:14 PM
Just rebuilt my transmission by Just Trans in Coburg.

I too had a vibration that is now mostly gone with a trans rebuild. I still have one that I suspect is the driveline central bearing. Its faint compared to original, but its there.

I have a long list of issues to deal with but thats gotta be done soon I suppose.

Check the bearing and the trans.