Knocking/clunking noise after going up mountains

Hi, I haven't posted for a while as Defender 2.5tdi 1989 has been sitting at my mechanics for 6 months while I decided whether it was worth chucking more money at it as the Power Steering Pump needed replacing. Decided to go ahead and it then passed its CT (MOT). However, after 20 kms up and down mountains (I live in the Volcanic National Park in France, so no real flat bits) it suddenly started to make this horrible knocking/clunking noise. Difficult to be sure where it was coming from as she could drown a radio if I had one with her normal running, lol, but think it was front, underneath - pouring with rain, so rain on roof didn't help, head stuck out of window so soaked....

Took it to my mechanic today, but on the way down the mountain decided to coast in neutrel to see what happened, again raining, window open to listen, soaked again. Of course the problem disappeared and when I got to the bottom and put back in to gear, all was fine, so when I got to the garage it was running fine. All street cred with mechanic now lost!!! He put it over the pit and couldn't find anything.

On the way home I came off one mountain and started to go up the second and the problem reappeared. It seems to manifest itself when the car is going uphill and the only thing I can think of is that I may have some cr*p in some part of the fuel system (sorry, sure there is a more technical term for this).

Can anyone offer any suggestions, any help would be appreciated.

Thanks.

Was it a drivetrain or engine related noise?

I don't know even know what a drive train is, sorry, will look it up: trying to keep defender on the road as it was my husband's pride and joy :-((

Was there any loss of traction when going up or down hill? If so did you use diff lock or at least low range?

No, no loss of traction, everything fine apart from noise. Have done search and nearest problem seems to be prop shaft thread. Will now investigate Prop Shaft. Thanks. Want to keep car on road as it was my husbands and I like driving it now he's gone.

JulesL said:

No, no loss of traction, everything fine apart from noise. Have done search and nearest problem seems to be prop shaft thread. Will now investigate Prop Shaft. Thanks. Want to keep car on road as it was my husbands and I like driving it now he's gone.

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sounds like the uj's on the propshaft.get underneath and give the props a damn good shaking,lets us know the results.

Yes. Propshaft......does that ring a bell with anyone? Pretty much sure, until told by my mechanic there was nothing wrong, that the problem was somewhere in that area. I always said it was steering column/bush related but not even sure that's near the propshaft? Husband always did the servicing on the car and until he died it had not been near a garage for 15 years so always ran like clockwork.....

Hi gemsdad, posts crossed..

What are ujs and how do I give props a good shaking )

I'll do what you say when I know what you mean.

JulesL said:

Yes. Propshaft......does that ring a bell with anyone? Pretty much sure, until told by my mechanic there was nothing wrong, that the problem was somewhere in that area. I always said it was steering column/bush related but not even sure that's near the propshaft? Husband always did the servicing on the car and until he died it had not been near a garage for 15 years so always ran like clockwork.....

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jules as you can understand,trying to diagnose a problem like this via a forum is difficult,people can only point you in the direction they think is the problem.is there no other garage you can take it to for another diagnosis??

JulesL said:

Hi gemsdad, posts crossed..

What are ujs and how do I give props a good shaking )

I'll do what you say when I know what you mean.

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uj's are universal joints,they allow a turning shaft to still move in a circular and vertical motion at the same time.they are fitted at either end of the props shafts.these are long round tubes that go from the end of the gearbox to the axles.get hold of these tubes and twist/shake them to see if there is any loose movement in them,there shouldn't be.

gemsdad said:

uj's are universal joints,they allow a turning shaft to still move in a circular and horizontal motion at the same time.they are fitted at either end of the props shafts.these are long round tubes that go from the end of the gearbox to the axles.get hold of these tubes and twist/shake them to see if there is any loose movement in them,there shouldn't be.

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^^^^ this but chock the wheels first so it cant roll and take the handbrake off

blue beasty said:

^^^^ this but chock the wheels first so it cant roll and take the handbrake off

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yes,i just assumed that would be done.

Wait a minute while I stop laughing.......no! No other garage in my area will touch my car as it is english and I can't fault the effort my mechanic has put in to keeping the defender running, he is a specialist in heavy goods vehicles. The nearest Landriver specialist is 70 kms away and I doubt the old lady would make it that far. Already spent 2k keeping her on the road since his death, which is more than she is worth, but she is 25 years old and all I have left of my husband......

So, do you think prop shaft?

Yep, that sounds like the problem. I just now need to go to garage and translate to french! Prop shafts.....you'd never believe I lived with a car dealer in my 20s, hence my somewhat hazzy, oft somewhere in the distance, car knowledge. Kisses, Jules xxxxx

JulesL said:

Yep, that sounds like the problem. I just now need to go to garage and translate to french! Prop shafts.....you'd never believe I lived with a car dealer in my 20s, hence my somewhat hazzy, oft somewhere in the distance, car knowledge. Kisses, Jules xxxxx

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ok,good luck with it and keep me/us informed please.might not be that but it is the place to start.