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Gearbox issue

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Old 18-03-23, 06:02 PM
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Default Gearbox issue

Hello everyone,

As my engine is running fine now and my steering is not binding anymore, I ran into gearbox issues.
It is hard to take out 3rd and especially 4th. The gears go in okay, but not as smooth as 1st and 2nd.

The behavior is always less than smooth, but the amount of binding force is varying. I can not see a
pattern/rule in that variation.

From the inside the gearbox looks overhauled. All synchros and the gears look almost new. There are
no signs of wear.

I have a complete workshop manual, but the information for desired clearances and dimension
inside the transmission is limited. in addition it would be nice, to have part numbers oder dimensions
for spare parts to narrow down my problem.

Is there anybody out here, who can help me? I can supply pictures and videos of the box if needed.

Christian

Last edited by Christalfa; 19-03-23 at 09:24 PM.
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Old 18-03-23, 06:06 PM
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Sorry double post, please delete one ....
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Old 22-03-23, 04:54 AM
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Christian,
It is difficult to comment on gearbox problems , especially when one does not know which car it is fitted to and the gearbox Type number (stamped on the RH side of the gearbox case)
Is the gearbox in its original form or has it had a remote shift fitted.

Geoff
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Old 03-04-23, 07:04 PM
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sorry for the delay, on the casing it says: BWCP9/314

I think this should be the original box from Borg Warner.

I have noticed that the bearing inside the bellhousing has spun. There is also some sort of loctite, maybe to prevent that from happening. Did not work ...

As there are already 3 big bearings holding the main shaft in the casing => What is the 4th bearing for?
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Old 11-04-23, 10:02 AM
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Christian,

From the gearbox number BW CR9/314 I assume it is fitted to an Arnolt Bristol.

If new Syncro rings have been fitted without checking the distance between
the 3rd and 4th ring it is possible that the Syncro ring does not have enough clearance to the gear and once engaged it could be come difficult to release from the tapered cone of the gear. Are those Syncro rings actually the correct ones for a Bristol ??
If this is the case the 3rd gear might need setting rearward a little and the input shaft moved forward a little .
The selector rod might then need shimming to centralise the fork in the middle of the movement of the selector rod.

The front bearing of the input /drive shaft should be a slide fit into the bell housing and should not have any Loctite on it . This bearing just helps
the alignment of the input shaft and takes almost no load.
Note all the bearings of the gearbox should not have any Loctite used .

Another tip is that the long cross bolts bolts of the main case should just be
nipped up to 40 inch lbs (not 30 foot lbs which can distort the alloy case and bearings ).

A further tip is that most modern bearings with a circlip are supplied with a thinner circlip than the groove in the bearing and groove in the main case .
This over time can allow the shafts and bearings to move in the case .

A Bristol gearbox rebuild should not normally be undertaken by a owner without experience with these gearboxes.

I hope this helps a little but it is very difficult to advise you without seeing the gearbox .
Good Luck
Geoff
Sydney/Australia
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Old 14-04-23, 03:36 PM
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Thanks for your support. I did not take apart the shafts/gears. The synchros are new and some bearings are as well. The Gearbox looks clean.

When shifting from 4th or 3rd into neutral by pushing the sliding piece by hand over the snchro and gear, the sliding piece is binding lightly on the synchro. In 1st and 2nd that is not the case.

Is there any manual, I can look up numbers for desired play? In the arnolt bristol workshop manual I can only find measurements for the distance between gears.

In addition: Can anyone give me a trustworthy gearbox specialist in central europe? As you say, I am actually hesitating to dive deeper into the box.
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Old 05-12-23, 01:47 PM
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Default Synchros needed

Hello again,

against my first impression the synchros seem to be old and a bit worn. The Gearbox shop would like to swap them. Can anyone give me a hint where to buy quality replacement parts?

The main problem, the binding of gear 3/4 while shifting was due to a low clearance of the sliding sleeve.

Christian
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