Fished out of my gearbox!

PostPost by: davidj » Sun Jun 26, 2016 7:38 pm

Ok, so what was it?!

My gearbox would not go into reverse. After following the very useful suggestions on this site, but unfortunately no success I have pulled my engine/gearbox out of the car (very stressful and definately not for the faint hearted!)

I took the lid off the box found a mangled piece of metal stopping the reverse from engaging. Has anyone any ideas what is was? From what I can see, the gears look in very good condition but I guess a complete stripdown is required to investigate further?

Cheers,

David
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PostPost by: el-saturn » Sun Jun 26, 2016 7:51 pm

in medicine they call this (or similiar) corpus alien - doesnt belong there - maybe one of the specialists can shit scrap metal - awesome in the most neg. form one refers to sandy -- the fellow who didnt notice this ate a hammer as they say here sandy, alps
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PostPost by: StressCraxx » Sun Jun 26, 2016 10:15 pm

It appears to be a "split cotter pin" or possibly a "roll pin" used to retain one part to another.
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PostPost by: Mick6186 » Mon Jun 27, 2016 6:48 am

When I rebuilt my 5 speed I made some adaptors to hold the selector forks in place when the selector rods were removed. These were then pushed out when the rods were replaced. My adaptors were made from metal tube and if you were forgetful they could be left in the gearbox when the selector rods were replaced. The pieces of metal in the pictures look to have been quite large diameter originally, almost as big as the selector rods, so maybe, if required during a four speed rebuild, the engineer overlooked one.
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PostPost by: Craven » Mon Jun 27, 2016 10:54 am

In the first pic, you can see on the left selector rod a split metal tube, this together with that clip thing on the rod limits the overthrow of the selector fork.
Size and shape of mangled piece resembles this tube, although can?t imagine where in the internal space an object of this size, other than on top of the selector rods, could lodge.
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PostPost by: davidj » Mon Jun 27, 2016 11:52 am

Yes, it does look like a very mangled tube. I don't know if there is a tube in the gearbox? I fished it out from the reverse idler gear, where it was vertical up against the case restricting the gear sliding into reverse. I can see why, from some angles it does look like a "split cotter pin", but appears to plate sheet steel.

Yes, it also occurred to me it may have been left behind during a gearbox "refurbishment" or maybe the metal cage of a seal, but again, how would it find its way into the gearbox?

Any more ideas are most welcome! I have rebuilt triumph gearboxes in the past, but unfamiliar with this design. It might be the split metal tube, and I will investigate this as well. Is there one on the reverse?


Cheers,

David
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PostPost by: CBUEB1771 » Mon Jun 27, 2016 1:03 pm

davidj wrote:I don't know if there is a tube in the gearbox?

There is a tubular sleeve over the 3/4 selector rod, however it looks like the sleeve is in place properly in your gearbox.
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PostPost by: gearbox » Tue Jun 28, 2016 10:45 pm

Yes, it is the sleeve that goes on the shift rod. Part number 23.
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PostPost by: davidj » Wed Jun 29, 2016 11:32 am

Thanks, but I don't think it is, as you can see from the photo's it is in place on my box. It may be another one, left accidently by someone refurbishing the box.
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PostPost by: gus » Wed Jun 29, 2016 1:17 pm

sure looks like a spare piece left in the box

question is what now?

the 'right' answer is tear it down and rinse every single piece out

rinsing it out repeatedly with kerosene is probably a 90 percent solution
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PostPost by: Hawksfield » Thu Jun 30, 2016 11:19 am

Hi

Sure looks strange, the amount of damage to this piece of metal could not of been caused in the box without the driver knowing. Also it looks like heat as been part of the damage.
Could it have been wedge in place for some time therefore not causing noise or damage ? if so why.

Like to see more photo's, what's the history of the box and when was it last opened
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PostPost by: rgh0 » Thu Jun 30, 2016 11:36 am

From the photos it sure looks like the sleeve tube that was left in the box and got mangled.

A few measurements would confirm it in terms of wall thickness and length and diameter.

My guess is someone was rebuilding a box and lost the sleeve in the bottom and then fitted a new one without realizing the lost one was still in the bottom of the case. Easy enough to do if you were doing it over a number of days. It then got mangled by the gears and may have sat happily in the bottom of the box again for many years before it finally jammed reverse.

cheers
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PostPost by: davidj » Thu Jun 30, 2016 12:05 pm

Good afternoon,

After further investigation, I am not 90% certain the mangled metal is the remains of a sleeve which goes on the shift rod as suggested by "gearbox", part no 23 on the illustration. It is a similar length and at the end, a bit of the curve is still visible. However, as you can see for my photos, the sleeve is still in place in my gearbox and the illustration does not show two. Is this the case and the other rods do not have sleeves? I can only guess the gearbox is a refurbished item fitted by a previous owner, and maybe the sleeve was left by whoever ?rebuilt? the box and has been rattling around since. I have not had the gearbox out, but then again, have not covered many miles either as I only got the restoration finished this year. One thing I did notice was the gearbox is earlier than the car, as there is no reverse switch, despite the car having reverse lights and the wires to the switch! This also confirms another gearbox has been fitted.

The good news is that if it is the sleeve, I have most of it and there is not any more in the gearbox. The condition of the box also looks OK as I have examined it with a borescope, so I am tempted to flush it, refit and hope for the best. Is rinsing with petrol (kerosene) the best option?

Cheers!
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PostPost by: davidj » Thu Jun 30, 2016 12:09 pm

Sorry, That should read "I am now 90% certain" !

Doh!
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PostPost by: rgh0 » Thu Jun 30, 2016 1:29 pm

The problem will be metal particles in the oil film inside the various bearings that will be hard to flush out. This is especially the case with the needle rollers and plain bearings on the gears on the main shaft. These will lead to accelerated wear and premature failure.

Having pulled the box out, stripping it down and inspecting and cleaning each component is not a long task in comparison and I would certainly do it.

cheers
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