Disco 300tdi knocking under load and on overun slightly

HonestJon007 · Dec 17, 2015

as title, gotten worse over last week or two, only happens under load, was just under heavy load now under any acceleration and also beginning to sound under overrun also. I have checked all oil levels =, all ok. uj's all ok. viscus fan, wobbly so removed. tappets nothing loose, adjusted when i got it. new aux belt. Serviced with correct 10.40 oil and new filters. Seems more noticeable when accelerating from low speeds/ stand still. getting worse and worrying me that it might just go pop somewhere, gut says transmission prehaps...

jamesmartin · Dec 17, 2015

you should be able to tell easily betwen engine and drive train,if engine get oil pressure checked or drop sump and check crank shells , if drivetrain remove 1 prop at a time and drive in diff lock

Dippypud · Dec 17, 2015

I'll bet on one of the diffs ...
usually ignored until they growl ...

HonestJon007 · Dec 17, 2015

Thanks for quick reply, is there an easy way to check the diffs? its coming from the front or at least not from behind. If I remove the front prop and it goes away then how will I know if its TB or diff? Doubt its big ends as there is no hint of noise such as this knocking unless clutch is engaged and under load, revving at standstill does not produce any knocking. Will pull front diff tomorrow and see what happens.

jamesmartin · Dec 17, 2015

HonestJon007 said:
Thanks for quick reply, is there an easy way to check the diffs? its coming from the front or at least not from behind. If I remove the front prop and it goes away then how will I know if its TB or diff? Doubt its big ends as there is no hint of noise such as this knocking unless clutch is engaged and under load, revving at standstill does not produce any knocking. Will pull front diff tomorrow and see what happens.

if it goes away with front prop removed ,issue is in front axle or the removed prop

HonestJon007 · Dec 17, 2015

ok thanks, if it matters the knock seems faster in low range and obviously not moving as fast either...hence me thinking TB

jamesmartin · Dec 17, 2015

that could be the case ,usually if removing both props doesnt effect it ,it is likely the t/box ot g/box, you can remove sump from t/box after draining oil to check its condition ie end float in gears or movement indicating bearing failure etc

HonestJon007 · Dec 17, 2015

Ok got it now, Might also have to double check valve clearance as it was dark and raining and only checked that none of the lock nuts were lose and the posts were still tight, even forgot to look at the caps to make sure one of those hadn't gone, none of the loose rockers were moving very much and I suspect that it would be noticeable at stand still if the tappets and associated parts were to blame just by revving it up. Did use a long spanner and no.1 injector seems to immit a knock at tick over that the others don't...I just cant be sure between a knocking engine when driving or a trans noise, have had engines start knocking and know the sound of big ends but LR's and 4x4's in general are new to me...noisy old beast at best of times...

Dippypud · Dec 17, 2015

HonestJon007 said:
Ok got it now, Might also have to double check valve clearance as it was dark and raining and only checked that none of the lock nuts were lose and the posts were still tight, even forgot to look at the caps to make sure one of those hadn't gone, none of the loose rockers were moving very much and I suspect that it would be noticeable at stand still if the tappets and associated parts were to blame just by revving it up. Did use a long spanner and no.1 injector seems to immit a knock at tick over that the others don't...I just cant be sure between a knocking engine when driving or a trans noise, have had engines start knocking and know the sound of big ends but LR's and 4x4's in general are new to me...noisy old beast at best of times...

You'd have done better giving the rockers a rock to see if any moved excessively ...

HonestJon007 · Dec 17, 2015

Well just driven home and I swear that the noise is less or different - the only thing I have done is tweak the tappets when checking if they are loose, so mat have narrowed it down. Tomorrow...

Dippypud · Dec 17, 2015

HonestJon007 said:
Well just driven home and I swear that the noise is less or different - the only thing I have done is tweak the tappets when checking if they are loose, so mat have narrowed it down. Tomorrow...

That'd be good ...

Disco 300tdi knocking under load and on overun slightly

HonestJon007

Member

jamesmartin

Well-Known Member

Dippypud

Never Knowingly Understood

HonestJon007

Member

jamesmartin

Well-Known Member

HonestJon007

Member

jamesmartin

Well-Known Member

HonestJon007

Member

Dippypud

Never Knowingly Understood

HonestJon007

Member

Dippypud

Never Knowingly Understood

Similar threads