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Discussion Starter #1
I was watching one of those YouTube videos by High Peak Autos and he was discussing the 3.0d crankshaft issues. He happened to mention that he felt that it was important to renew the transmission fluid at timely intervals, otherwise the transmission could cause strain on the crankshaft and subsequently cause the crankshaft issue.

It sounded more like his opinion because he didn't reference where he sourced this theory/fact from, but could there be any truth in this?
 
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I'd have thought the whole drivetrain would cause 'strain' on the crankshaft.
 
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Quite Neill.. crock and poo spring to mind...
 
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Discussion Starter #4
I'd have thought the whole drivetrain would cause 'strain' on the crankshaft.
I would guess he meant "extra" strain.
 

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I use to have a Peugeot 406 manual and I replaced the gearbox to Auto. The “recommended“ timing belt changes are 60k and mine snapped at 40k. The mechanic believed in the same thing that auto gearbox put more strain on engine compared to manual.
 

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I use to have a Peugeot 406 manual and I replaced the gearbox to Auto. The “recommended“ timing belt changes are 60k and mine snapped at 40k. The mechanic believed in the same thing that auto gearbox put more strain on engine compared to manual.
What about this guy's theory (or wherever he got it from) that not renewing the transmission fluid could cause additional strain? I could see how there may be more strain on the transmission, but I can't seem to visualise how it could effect the engine?
 

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I thought the crankshaft issues were because of the bearings rotating within the big end, covering the lube hole?

If that's the case - it wouldn't matter how often you replace the oil.
 
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What about this guy's theory (or wherever he got it from) that not renewing the transmission fluid could cause additional strain? I could see how there may be more strain on the transmission, but I can't seem to visualise how it could effect the engine?
It’s because of the harsh gear changes that would put more stress. Like rotational hammering on the crankshaft. Tbh when I sent my crankshaft for grinding after that spu bearing they said it needs some alignment on mains. It be this.
 

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I thought the crankshaft issues were because of the bearings rotating within the big end, covering the lube hole?

If that's the case - it wouldn't matter how often you replace the oil.
What Graham suggested could be cause of a spun bearing.
 

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Discussion Starter #10
It’s because of the harsh gear changes that would put more stress. Like rotational hammering on the crankshaft. Tbh when I sent my crankshaft for grinding after that spu bearing they said it needs some alignment on mains. It be this.
I never thought about the harsh changes, interesting. Food for thought I guess.
 

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I never thought about the harsh changes, interesting. Food for thought I guess.
When you go to D or N and you have a chance to see engine you will see how much it moves. All that is an impact on crankshaft and other moving parts. That is not the case when you have a clutch.
 

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When you go to D or N and you have a chance to see engine you will see how much it moves. All that is an impact on crankshaft and other moving parts. That is not the case when you have a clutch.
So another reason to keep her in Drive when sitting at the lights etc? :)
 

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So another reason to keep her in Drive when sitting at the lights etc? :)
I always keep it at D unless I know I have waiting for more than 1min. These boxes are more clever that people think. The car won’t overheat if you keep it at D. Keeping it engaged will only put stress on oil but changing it will put stress on bands, friction plates, solenoids, an probably moving parts of engines.
 

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I would guess he meant "extra" strain.
I’d do that 😁

But if their tolerances are that tight, it’s a bad design somewhere.
 
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When you go to D or N and you have a chance to see engine you will see how much it moves. All that is an impact on crankshaft and other moving parts. That is not the case when you have a clutch.
I’d have to question that.

My R-S has the quick-shift box. The changes can be quite severe at near-line engine speeds. The Change in engine speed will therefore impact the crank immensely. But there’s no such 5.0 failures.
 

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The forces on the crank during a gearchange must be miniscule compared to the force exerted on it every time you hit the brakes.
 

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I’d have to question that.

My R-S has the quick-shift box. The changes can be quite severe at near-line engine speeds. The Change in engine speed will therefore impact the crank immensely. But there’s no such 5.0 failures.
This should have been covered in the design. 5.0 is a completely different engine and for sure the crankshaft and many other parts are stronger. Also the harmonics due to those impacts are different as well as tolerances due to being a higher performance engine.
The idea was that harsh changes will accelerate the crankshaft failures or spinning a bearing.
 

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The forces on the crank during a gearchange must be miniscule compared to the force exerted on it every time you hit the brakes.
Gear changes happen in fracture or a sec while when you brake there is delay between releasing the gas pedal and brake. Then there is long way between tyres to crankshaft. I would compare harsh gear changes with hard kickdowns though.
 

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Gear changes happen in fracture or a sec while when you brake there is delay between releasing the gas pedal and brake. Then there is long way between tyres to crankshaft. I would compare harsh gear changes with hard kickdowns though.
It doesn't really matter how long it takes to get there ... it's still a considerable force when it arrives.
 

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It doesn't really matter how long it takes to get there ... it's still a considerable force when it arrives.
What I meant was ECM have time to adjust the fuel injection and timings so that forces acting on crankshaft from connecting rods matches the resistance from gearbox. It’s not a shock when engine is set to accelerate and instead of an smooth transition a rotational shock is exerted on the crank end.
 
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