Diagnosis Requested - Post Lift Noises

[Jimmu]

I have recently lifted the beast 2"

Since I have encountered a strange noise from the drivetrain.

The noise is like a light to medium grinding type noise that seems to be coming from the rear of the gearbox as much as I can tell.

I thought at first it was the tailshaft. But further experimentation lend me away from this conclusion.

The noise only occurs in 5th.
It occurs when you are at that point between acceleration and deceleration. Ie lightly coming off the juice on the highway where you are just starting to slow down and not speeding up. (If this makes sense)

Most noticeable around 110 but once you know what to listen for is there above 80.

I notice that the expansion joint on the tailshaft is extended quite a bit from stock after the lift. I am wondering if this may be the cuase as the position is about correct to make the noise.

Maybe the added angle (which does not appear extreme) may be placing extra pressure on the gearbox?

Suggestions would be appreciated as would possible fixes.

Thanks

Jimmy.

[justin]

That sounds just like the noise I got when I lifted mine and left the Ext. shackles on, same sort of speed and like a low pitch grinding noise when you back off. I guessed it would be tail shaft vibration when just rotating and not being driven, but I could not be bothered to find it out exactly so I whipped off the shackles and it went away. The rear arch was 970mm off the ground when it was happening and when it dropped to 940mm it was gone.
J

[Jimmu]

Thanks Justin,

I have the standard shackles that were supplied with the springs.
I will measure the lift and see where she is sitting.
Hopefully I can find a fix without lowering it as it is a good height now

Jimmy.

[justin]

Let me know if you locate the rattle as I would like to stick the Ext shackles back on and get nose bleeds again! J

[geeves]

On Nissan Safaries with big lifts they quite often have to rotate the rear diff slightly to overcome this using a thin wedge. Otherwise you could try lowering the rear of the gearbox slightly. Also make sure your universals are in perfect condition.

[Jimmu]

When I got the allignment done they reckon I need to get an extended drive shaft.

I am looking for some way to avoid that as it is damn expensive.

Twisting the Diff sounds like a good idea...

Maybe a spacer of some description. Maybe on the diff where the cup thing bolts on to bring the tailshaft forwards a bit. 10mm should do the trick.

That may actually work...

I wish I still had access to a water cutter...

Jimmy.


P.S. They censor Damn? Crikey! Thats going a bit far.

[justin]

I thought that may be the case. I actually wondered if a thin wedge between the leaf springs and the rear axel mounts causing the diff to rotate towards the drive shaft may work. But I haven't really got underneath and had a good look yet. J

[Graham]

In my hoon days, I blew the CV, bearings and driveshaft in my little FWD thash box. The cost of replacing both driveshafts with heavy duty custom items was only a little more than replacing the one stock drive shaft. Maybe if you shopped around you'd find custom shafts at an OK price??? I think there's a diff specialist in Parramatta near my work, plus I'm sure there's lots around elsewhere. Not sure if they could do something at a decent price...

[Jimmu]

I have been trying to source a spacer for the beast. They make them for Cruisers, Patrols, Hiluxes and Sierra's but not for Rodeo or the MU.

Getting the tailshaft extended is a $300+ Job which I think is expensive and takes them 3 days to do it.

Does anyone have any idea where to get a spacer for the tailshaft?

I could make one up, but I really do not have the time, so I would prefer just to buy one.

Jimmy.

[geeves]

Measure it to be sure but I think the hilux one fits

[Jimmu]

Ok will do. I might whip it off tommorow and take it down to the boys at slacks creek who sell the spacers and see.

Thanks.

Jimmy.

[Jimmu]

Damn I have been stuffing around with this for a while!

But I will have delivery of a custom made ISUZU MU 25mm tailshaft spacer on Friday.

Hopefully it will fix my vibration issue described above.

I will let you know how it goes.

Jimmy

[Jimmu]

errmm update. Spacer did nothing. Something else is to blame!

Tailshaft expert tells me unis are fine.

Shagged if I can work it out.

Jimmy