Thread: LT95 gearbox noise

Hi Adrian,
That sound is normal. They rattle. Someone posted the reason recently, but it is not at all detrimental to the vehicle's operation or longevity.
Enjoy your trip and post lots of photos!

Hi Adrian,

Seems to be a normal thing with the LT95.

See this thread:
Change in engine sound when idling - clutch in/out. Normal for an Isuzu?

and this thread:
Castrol Super RX vs VMX-80 in LT95. Real world report.

I gather by clutch 'out' you mean with your foot off the pedal, and by 'engaged' you mean with your foot on the pedal (in other words, the opposite to the normal use of the words).

If I am correct in my interpretation of your meaning, this is perfectly normal. The engine accelerates and and decelerates twice per revolution due to the large cylinder size, high compression and relatively light flywheel with only four cylinders. As this happens the free play on the constant mesh gears flops back and forth twice per revolution, creating the noise you hear.

The effect can be minimised by increasing the idling speed slightly, better by fitting a hand throttle so that it can be increased as necessary for different temperatures and degrees of warming up.

John

Originally Posted by spudboy

Hi Adrian,

Seems to be a normal thing with the LT95.

See this thread:
Change in engine sound when idling - clutch in/out. Normal for an Isuzu?

and this thread:
Castrol Super RX vs VMX-80 in LT95. Real world report.

Also happens with factory LT85 equipped Isuzu Landies.

Also, apart from the oil change stuff in the 2nd link in my previous post, I got great improvement by increasing the idle slightly.

Just 100 or so RPM higher and the gearbox rattle was significantly improved, especially when hot.

A very common noise issue with the LT95 comes from the "finger" of the Hi/Lo selector. It should have a plastic sleeve on the finger, but they break up when they age. Without the sleeve they produce considerable noise rattling in the selector fork.

All that is needed is a piece of oil and heat resistant plastic tube pushed over the finger.

if you look at the back of your injection pump, there are TWO big nuts

thay are actualy covers. inside the bottom one is the idle ajustment screw. best to use this and not the cable

Originally Posted by 85 county

if you look at the back of your injection pump, there are TWO big nuts

thay are actualy covers. inside the bottom one is the idle ajustment screw. best to use this and not the cable

That is the idling spring adjustment, not the idle speed adjustment. the idle speed adjustment is on top of the governor.

The idling spring adjustment is for the governor to maintain the idle speed when the load changes, eg air con compressor clutch engages/disengage, or the road grade changes up/down.

The stock idle speed is on the low side and the torsional vibration will be improved if the idle speed is increased, via the idle speed setting screw on top of the governor.