911 Gearbox mounts - static position/ARB clearance

[Gary71]

I'm seeking some guidance on how much clearance you have from ARB to gearbox mount, specifically early 911 with 915 box.

Recently I've been getting a clunking noise from the back of the car and narrowed it down to the rear ARB whilst driving.

It's always been close (no more than 10mm) but it's now about 1mm away.

I'm thinking the gearbox mounts have failed, but before I invest in a second set (these are about 10 years old) I'd appreciate a second opinion.

This is how they look now also showing he ARB clearance: (dirt phobics look away)

[Gary71]

I've since pulled the x mbr off and the mounts look absolutely fine.

So other than putting a spacer under the ARB mounts I'm not sure what next!


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[Gary71]

I'm taking to myself I know, but the problem is the ARB mounts, not sure they should be this shape:

Last year I grounded in a large unseen pothole in a snow covered car park, I guess this was the result!

Hopefully once this is back in the right place the ARB will clear.

[fetuhoe]

Gary,

The Transmission mount doesn't look correct.

The mount should bolt into place from underneath the cross member and I don't know what the thick block that looks like rubber is doing but it is not part of the standard arrangement.

It looks as if the mount has been bolted in from the top and spaced down.

Was your shell originally fitted with a 911 (late spec 901 style) box which would be the case in a very early 2.4.

If a 915 has been retrofitted there will be a small difference in the shell and the 915 could touch the rear of the body and this change may have been doe to lower the box.

The end of the tunnel on the earlier shell is slightly narrower and this is why there is a potential issue.

We have seen this problem once before.

[Gary71]

Hi, I've some more pictures of the mount out of the car below and I think it's ok to your description. The mounts are bolted in from underneath, and there are no spacers, except the ali plate between the box and x mbr.




It's a fairly early 2.4 (00226), and I've no reason to think the box has been changed, but its history is patchy to say the least so who knows!

I've reworked the ARB mounts back to square now and I'm just repairing the underseal on the floor before putting it back together.

[fetuhoe]

the steel pressing is more radiused than I am used to seeing and with it off the car it is what I would expect to see.

[Gary71]

Cool. Hopefully once the bar goes back on it will have some clearance again.


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[Gary71]

Back to a massive 8mm gap again. Fingers crossed this is enough to avoid contact.



Always nice to find some original paint when working under the car:


Now covered in underseal of course!

[911hillclimber]

mine is as close as yours Gary, 73T 915 from factory.
I have that 3mm alloy spacer too.

It certainly does not look right in the first picture. Will have a closer look tomorrow after my MoT.

[Gary71]

All ok now I hope Graham, just bent ARB mounts. My mot has also expired!


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[911hillclimber]

Snap. Mine expired on 4th July.
8.30am tomorrow for the nail biting 45 mins.
Glad it's sorted.

[hot66]

Viper green ... One day Gary ?

[Gary71]

One day indeed


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