Drivetrain clunk

Technical MGB discussion
Ian F
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Re: Drivetrain clunk

Post by Ian F »

When you drain the old oil out check carefully for any metal sludge or particles. After such a short mileage with the wrong oil I think you probably have got away with it.
I suspect wear in the cup washers.
As said before, these axles can clunk for years and still function.
The noises signifying the end are usually loud screeching or grinding noises.

Ian F
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whitestu
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Re: Drivetrain clunk

Post by whitestu »

Thanks - There's never been any obvious sludge or metal particles that came out when I changed the washers and shims, and other than the clunk the axle is very quiet so hopefully no serious damage.

I've changed the shims and cup washers twice now. Second time was to fit the +40 thou thrust washers so I swapped the cup washers as well. When I first changed them one of the cup washers was worn but changing it made no difference to the clunk.

Checking back on my oil used, when I first changed the shims / washers in June this year I did use hypoid oil so the car ran for a year, but not very many miles on non-hypoid.

I suspect using non-hypoid may have worn the crown wheel / pinion so I'll either have to put up with the clunk or get a reconditioned axle.

Cheers

Stu
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Bumpa
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Re: Drivetrain clunk

Post by Bumpa »

You can get a clonk if wire wheel splines are worn. Do you have wires? If yes, it's worth checking they are clonk free when fully tightened up.
Mike
1969 MGB GTV8 3.9 Conversion. Many classics have passed through my hands but the faithful BGT V8 is the last man standing.
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Re: Drivetrain clunk

Post by whitestu »

Good thinking but no, I don't have wires. I did once change an Alfasud gearbox chasing a clunk only to find the wheel bolts were loose on one side though :?
Ian F
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Re: Drivetrain clunk

Post by Ian F »

Definitely try oversize cup washers if the ones you fitted were standard size. That's what worked for me.

Ian F
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whitestu
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Re: Drivetrain clunk

Post by whitestu »

Thanks, I'll try to find some
Not_Anumber
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Re: Drivetrain clunk

Post by Not_Anumber »

I'm sure you already have, but have you checked the propshaf joints for any free play ?
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whitestu
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Re: Drivetrain clunk

Post by whitestu »

Not_Anumber wrote: Sat Jul 20, 2024 5:13 pm I'm sure you already have, but have you checked the propshaft joints for any free play ?
There is a very small amount of play in the rear propshaft joint but so small it is quite hard to spot it. I will change the joints this week though.

I took the diff cover off again to try to assess where the play is and it is pretty obvious that 95% of it is in the spline joints where the half shaft goes into the sun gears. The pinion and crown wheel has hardly any free play as so the sun/planet gears with the oversized shims.

Question now is whether the half shaft or planet gear splines are worn, or more likely both, and whether it's worth trying to fix.
Ian F
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Re: Drivetrain clunk

Post by Ian F »

Whereabouts are you? Probably not near Edinburgh I would guess?

I have spare axles, drive shafts etc., not new of course, but may be serviceable. You would have to inspect them though before considering trying to fit them

Ian F
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Re: Drivetrain clunk

Post by whitestu »

Ian F wrote: Mon Jul 22, 2024 9:57 pm Whereabouts are you? Probably not near Edinburgh I would guess?

I have spare axles, drive shafts etc., not new of course, but may be serviceable. You would have to inspect them though before considering trying to fit them

Ian F
Thanks for the offer, but I'm just North of London so a bit of a trek! I took the prop off this morning so will put new joints in today and see how things feel when back together. TBH I'll probably just live with it.
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