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RRC load noise when in drive!


steve200TDi

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I have a noise! That's not meant to be there!

Back story:

This is my Dad's 100 inch blue pick up ( you may have seen the megasquirt install:

A couple of times now, he's been driving along and then suddenly a tin-y tapping sound which is quite load occurs. He stops to have a look, can't see anything, starts the engine and sometimes it goes away and sometimes it doesn't. I've heard it myself just moving it up and down the driveway, but can't determine where the sound is coming from.

It stops when you come to a stand still withe the engine running and so we can rule out the engine. I had wondered if it was the starter gear just sliding foward and catching, a) I don't know if this is possible and b) I don't think it would make that sound!

I've had the access plate off at the bottom of the bell housing and it looks all clean in there with all the bolts where they should be with no oil at all.

There's nothing touching the propshafts too.

Last week we removed the propshafts to check the transfer box (borg warner)

I had heard from googling that the chain to get slack and jump a tooth. I was convinced it was this until I found the chain isn't that slack! With the gearbox in park I can roate the drive flanges aless than a 1/8 of a turn, but I cannot rotate them independently - Is this right? I have one in the garage which I can rotate separately? I also checked the chain through the oil fill hole and moved it up and down to check the slack and it wasn't that slack and certainly not enough to jump a tooth.

I think it's got to be part of the drivetrain as it happens when you're going along and not stationary. We checked the diffs by rotating them and they seem fine. We haven't removed them to check crown wheel bolts etc.

Could it still be something to do with the autobox of transfer box? If the gearbox shift was mis aligned would it misbehave or would it simply do nothing?

We're going to drop the oils next to see if there's any debris, but I'm at a lose without taking things apart!

Any ideas?

Steve

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Sounds like you have been down most sensible paths already.

Have you checked the handbrake adjustment? I assume you have given you have had the back off the transfer case.

Also assuming you have checked propshaft UJs.

Misaligned autbox linkage would just lead to you not being able to get into park/first, and the other indents being a bit offset/random.

My money on this is going to be a cracked flex plate though, sounds tinny/graunchy and stops when not under load. Unfortunately this is a box out job (or at least pushed back), so by all means pick on someone else's ideas first!

The transfer box which allows you to rotate front and rear flanges is very broken, unfortunately.

 

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1 hour ago, Bowie69 said:

Sounds like you have been down most sensible paths already. We've tried to check all avenues!

Have you checked the handbrake adjustment? I assume you have given you have had the back off the transfer case. I haven't, I maybe should have checked.

Also assuming you have checked propshaft UJs. One of the front UJ's has slight play and will be replaced.

Misaligned autbox linkage would just lead to you not being able to get into park/first, and the other indents being a bit offset/random. I thought that maybe the case, just nothing would happen, so I can rule that out!

My money on this is going to be a cracked flex plate though, sounds tinny/graunchy and stops when not under load. Unfortunately this is a box out job (or at least pushed back), so by all means pick on someone else's ideas first! Ah! This could fit the tin-y sound I'm hearing as the flex plate is thin! Does the flex plate transmit the load from the back of the crankshaft to the big doughnut in the bell housing. I guess it makes the sound, you stop, the load is released, the sound stops, you drive on. It did happen just driving back and forth in the drive way, but that was after a short drive. An avenue to pursue I think!

The transfer box which allows you to rotate front and rear flanges is very broken, unfortunately. Ah! Good to know! I may bin it then, or not fit it!

 

Thanks Bowie, alway a wealth of knowledge!

Steve

P.S. Regarding the flex plate, how is the sound achieved? Where does it crack and how does it still transmit drive?! I guess you wouldn't see much (or anything) looking through the access hole of the bell housing - as I didn't!

Edited by steve200TDi
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1 minute ago, steve200TDi said:

Ah! This could fit the tin-y sound I'm hearing as the flex plate is thin! Does the flex plate transmit the load from the back of the crankshaft to the big doughnut in the bell housing. I guess it makes the sound, you stop, the load is released, the sound stops, you drive on. It did happen just driving back and forth in the drive way, but that was after a short drive. An avenue to pursue I think!

Essentially yes, that's my theory at the moment. As you say it connects the crankshaft to the 'big doughnut' (torque convertor) that sits in the bellhousing.

it is tricky to see unfortunately, without removing the box :(

Could just be a brake dust shield or a rattly exhaust though! ;) 

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I thought the BW with the viscous centre should allow one wheel to turn with resistance when jacked up ? What happens when you drive in a full lock circle ? any tyre slip ?

That said , it does sound like it could be a cracked flex plate , and as Bowie says engine and box need to be separated to see it properly . If it is cracked definitely check the end float clearance on the torque converter when you re-assemble .

It could also be a loose baffle in a silencer ..

cheers

Steve b

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19 minutes ago, Bowie69 said:

Essentially yes, that's my theory at the moment. As you say it connects the crankshaft to the 'big doughnut' (torque convertor) that sits in the bellhousing.

it is tricky to see unfortunately, without removing the box :(

Could just be a brake dust shield or a rattly exhaust though! ;) 

I already checked, it has no brake dust shields!!

Yes, maybe an engine out job......The engine mounts need replacing anyway and so it's only a few more bolts!

Steve

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6 minutes ago, steve b said:

I thought the BW with the viscous centre should allow one wheel to turn with resistance when jacked up ? What happens when you drive in a full lock circle ? any tyre slip ?

That said , it does sound like it could be a cracked flex plate , and as Bowie says engine and box need to be separated to see it properly . If it is cracked definitely check the end float clearance on the torque converter when you re-assemble .

It could also be a loose baffle in a silencer ..

cheers

Steve b

I thought the same thing as it has a 'limited slip' diff, but maybe more torque needs to be applied rather than just a hand?!

Yes, I've just been reading up on all the flex plate aligning threads!

Steve

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Yeah exactly, there is workshop manual figures, but it is stiffer than hand tight.

The test for when fitted to a vehicle, is put a 2' wheel brace on a raised front wheel and stand on it -it should sink to the floor slowly -obviously do this in the direction for doing UP the wheel nut ;) 

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You can of course just change out the viscous, and have a good transfer box:

https://www.ashcroft-transmissions.co.uk/viscous-couplings/range-rover-viscous-coupling.html

Note the 27Nm of force required in the FAQs for a bench tested unit, essentially what Steve was doing by grabbing the flanges.

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  • 1 month later...

An update on this.

Yesterday I took the lower cover plate off of the auto box to expose the internal flywheel, torque converter, flex plate. I also removed the little inspection hole cover plate too.

On rotating the engine it all looks perfect; no oil, no cracks, no noises, nothing!

So I find it hard to believe something can be making a noise in there!

So the plan going forward:

 - Replace engine mounts - as they need doing!

 - Inspect and service starter motor - I did think that if the starter motor gear doesn't return fully then it could catch and make a noise. I'm not entirely sure how it works, will have a look at a spare in the shed, but it wouldn't hurt to remove and inspect anyway.

Hopefully I can do both of those without removing the exhaust, but we'll see!

Then it'll be a test drive/use and see if the noise comes back.

If it does, I'll be onto inspecting the diffs!

Steve

 

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Prop UJs can’t be checked without removing the prop from the vehicle - you have to check for play, binding and notchiness.

I had a problem with the rear diff of my wife’s 90.  The roll pin securing the cross-pin in the carrier kept shearing, allowing the cross pin to slide out against the inside of the ring gear and contact the pinion head on every rotation.  It was only audible at around 30-mph on the overrun, and it sounded like a rattling rear door.  I think the recurring roll pin failures may have been caused by a worn cross pin or oval used cross pin holes in the carrier.  The pinion head had quite obvious witness marks and the edge of the cross pin was chipped, both visible looking in through the filler hole with a torch while rotating a wheel.

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3 hours ago, Snagger said:

Prop UJs can’t be checked without removing the prop from the vehicle - you have to check for play, binding and notchiness.

I had a problem with the rear diff of my wife’s 90.  The roll pin securing the cross-pin in the carrier kept shearing, allowing the cross pin to slide out against the inside of the ring gear and contact the pinion head on every rotation.  It was only audible at around 30-mph on the overrun, and it sounded like a rattling rear door.  I think the recurring roll pin failures may have been caused by a worn cross pin or oval used cross pin holes in the carrier.  The pinion head had quite obvious witness marks and the edge of the cross pin was chipped, both visible looking in through the filler hole with a torch while rotating a wheel.

Another avenue to pursue! I'll certainly be having a look at the oil and in through the filler hole and probably removing the diffs too!

Thanks

Steve

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The oil wasn’t contaminated any more than usual as the damage was so small - the cross pin was just clipping the flat end of the pinion head.  The chipping was no more than 0.5mm built up over a year or more, and the pinion marking was entirely superficial with what looked like small moth wings.  You won’t find metal grains in the oil, either.  You’d only see it by looking through the filler.  The interesting thing is that this was a recurring fault on a diff with less than 25,000 miles from now on a three four year old vehicle that had never towed and never been off road.

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  • 2 months later...

 

I'm still trying to sort this. i phoned a local auto box specialist today which recommended undoing the flex plate bolt to look at the blocks they go into on the torque converter - these could be cracked where they are welded on. Worth a look I suppose.

I've also email Ashcrofts, so awaiting there feedback.

I've also attached a short video clip of the noise!

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  • 1 year later...

So to update this, as it's been over a year, wow!

We've taken the start out - looks ok.

We've trained the BW and auto box - no lumps of metal, all good

We've removed the two boxes - this was last autumn inbetween lock downs and before the bad weather hit!

Flex plate looks fine with no cracks

Looking in through the filler hole of the Borg Warner i can see the chain, still a nice clean grey colour and I've pushed the chain from left to right and I thought that that wasn't an excessive amount of chain slack.

We'll take the auto box to a local reconditioning coming to have it checked over beings it's out.

Does anyone know of any local Hampshire/Sussex/Kent places that would have a look at a Borg Warner transfer box or what things can go wrong?

I know of chain stretch, the viscous locking up, but apart from that there's not much else to look at.

I will check the starter again for gear springyness of it sliding out and catching the flex plate. It's almost worth fitting a new starter.

Plan of action is try and get both boxes checked over, refit, maybe new starter and see what happens.....

Regards

 

Steve

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You are right, the BW is very simple, just bearings, chain and viscous.

You can service the BW box very simply:

https://www.ashcroft-transmissions.co.uk/diy-rebuild-kits/borg-warner-rebuild-kits/rrc-rebuild-kit.html

Add a chain:

https://www.ashcroft-transmissions.co.uk/diy-rebuild-kits/borg-warner-rebuild-kits/borg-warner-chain-classic.html

You can test the viscous coupling on the bench as well:

1) Secure the output shaft ...

2) Apply a clockwise torque of 27 Nm to the (front propshaft) output flange nut. If no resistance to turn is felt, unit requires replacing.

3) If resistance to turn is felt, apply a clockwise torque of 20Nm to the (front propshaft) output flange nut for 1 minute, this should result in a rotation of approximately 25 deg - 30 deg. If no rotation or a greater force is required, unit requires replacing.

27 Nm = 20 lbf-ft 20 Nm = 15 lbf-ft

 

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  • 2 months later...

 

A long overdue update!

The autobox was sent here: https://www.automaticgearboxcentre.co.uk/ and they did some checks to it. Oil pump is good, the clutch pack was showing signs of wear, so that was replaced, and the torque converter was also sent away to be checked over. So it all looks good.

The transfer box looks ok, the two output shafts turn together and there is resistance between the two, i'll check it again once it's back in.

So last week, I finished the chassis repair behind the gearbox crossmember (interesting rust was holding it in and was a pain to remove with hammers etc....it just slide in on refitting...I was surprised!), gearbox and transfer box in along with wiring, starter (gear spring back so no signs of it catching on the starter ring), handbrake etc. 

I also removed the flexplate and starter ring and it was all perfect, no cracks or nicks etc.

So my Dad will be fitting the seats and propshafts this weekend. Everything else is fitted and we'll add some oil next week and see if it moves, then it'll be onto an MOT and go and use it. 

Unfortunately we haven't found anything definitive that has caused the noise and so we'll have to wait and see if it comes back, is still there or we find it now we've disturbed a lot of things!

Steve

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