Gearbox access panel

[John Mellor]

Hi all, whilst having removed the (fibre glass) cover I thought it would be sensible to cut an access panel. Doubt about my ability to cut in the correct place and also what/how to organise a cover for the hole. Any suggestions welcome before I raise a scalpel !!!

Regards

[ianc]

When I fitted a split gearbox cover, I took photos of the whole process and made this note:

Note: The red tube at floor level is the rubber sheathing for the petrol pipe – brake and petrol runs from front to back are taken through the cabin so that they cannot be ripped off the underside of the car.  Photos 1447 & 1451 - The aperture for access to the gearbox filler plug is centred about 9.75" back from the leading edge of the cover (unfortunately, the flash makes it difficult to read the measurement!).

I changed the gearbox/overdrive oil about a month ago (before the freeze!), and had no problem filling the gearbox using the Penrite plastic container with flexible plastic tube.

Hope this helps

Ian Cornish

[John Mellor]

Thanks Ian, from where did you source the rubber plug?

[Ralph Whitaker]

1 hour ago, John Mellor said:

Thanks Ian, from where did you source the rubber plug?

That looks like the standard TR3 plug for access to the propshaft grease nipple, but on my car I used a plug from the jack hole in the floor which is a little larger I think.

Ralph

[ianc]

I think I used the rubber bung which was in the original (not split) gearbox cover, but it was a few years ago and I can't be sure.

Ralph's advice is helpful, and those bungs will be in the Moss catalogue.

Ian Cornish

[rcreweread]

John - you don't actually say which hole/cover you are wanting to do - if your car has overdrive, you ideally need two holes and covers - one for the filler plug which is what the above responses refer to and the other to get access to the right angle drive for the speedo which is on the RH side of the tunnel.

Original OD tunnels had a curved and bulbous shaped steel cover for this which was held onto the tunnel with 3 self tappers. Couple of photos of one attached - I might have a spare one if you want one - PM me if you do

Cheers Rich

[John Mellor]

Many thanks folks. Rich, I sent a PM

[BlueTR3A-5EKT]

11 hours ago, John Mellor said:

Thanks Ian, from where did you source the rubber plug?

Looks like a 605602 transmission tunnel plug that fits a 2 1/2” hole. For access to universal joint and gearbox fill dipstick.

[Nigel C]

I found you can drill a few holes and look throught to make sure your directly where you want the hatch to be. Then cover that area in tin foil and fibre glass it up. Then pop it off the tin foil and you have a perfect match in surface shape to the area you want to cut away.

Shape the piece using jig saw/sander etc and place back on the tunnel surface. Draw a line around and then project a line within this by around 10mm. cut out to the INSIDE line. Drill four holes and self tapper on.

I have now gone over to riv-nuts to hold these inspection panels on due to inspecting to many times 

 

 

[stillp]

I used a rubber plug intended for the jack hole in hte TR4 floor.

Pete

[ianc]

I made some measurements this morning.  In 2004, I must have cut the circular hole using the 2.25" cutter from my set of circular cutters, which go to 2.5".

The 2.25" hole gives a snug fit to the bung, which is the same size as that on the propshaft tunnel - Peter says this bung is 605602, and I'm sure he is correct.  The hole in my steel propshaft tunnel is also 2.25" diameter, giving a snug fit.

I think that cutting 2.5" hole would make a loose fit, and that would be undesirable.  If one hits a large puddle, a loose bung could get blasted out and the water would hit carpet, passenger and left floor!

Ian Conish.

[stillp]

I can't remember what size hole I drilled for the floor grommet, but it certainly isn't loose. I can't check the car as it's away at TRGB, but I'll have a look at my holesaw set to see which one I used.

Pete

[Ralph Whitaker]

2 hours ago, stillp said:

I can't remember what size hole I drilled for the floor grommet, but it certainly isn't loose. I can't check the car as it's away at TRGB, but I'll have a look at my holesaw set to see which one I used.

Pete

If using a jack hole floor bung you need a 2.75 inch (70mm) hole, or for more room use a Land Rover transmission tunnel bung, Britpart no 334189, available on ebay, which needs a 3 inch hole.

You can of course use the TR propshaft greaser bung, but that is quite a bit smaller, Ian says 2.25 inch diameter.

Ralph

[stillp]

2 hours ago, Ralph Whitaker said:

 

the TR propshaft greaser bung, 

 

Every day's a schoolday - I didn't know there was supposed to be one! I've always greased mine from underneath.

Pete

[Ralph Whitaker]

On 12/22/2022 at 4:13 PM, stillp said:

Every day's a schoolday - I didn't know there was supposed to be one! I've always greased mine from underneath.

Pete

Think they did away with it on the TR4s

Ralph

[ianc]

Perhaps because my Works' TR4 has a modified chassis, with much larger and stronger plating above and below where the exhaust passes through the centre of the chassis, there is no access from beneath to the grease nipple at the front of the prop shaft, and there is a bung in the metalwork of the propshaft tunnel to permit access from above.

In addition, to permit me to grease the sliding spline of the propshaft (also inaccessible from beneath), I have drilled a hole behind the big bung, plugging it with a small rubber bung.

In the attached photo, the bungs for the gearbox filler and the propshaft greaser are visible, but the small bung for the sliding spline is a little further back.

Ian Cornish

[stillp]

3 hours ago, Ralph Whitaker said:

Think they did away with it on the TR4s

Ralph

That's what I thought, but the Moss catalogue shows it.

Pete

[ianc]

My TR4 Parts Manual, Second Edition, 1st Printing, does not show a hole for access to the front end of the propshaft.

Both the paper and on-line Moss catalogues don't appear to show a hole, but list the bung/plug (item 131, 605602).

Perhaps an owner of a standard TR4 could tell us what is (or is not) in his/her car - and the year of manufacture, because there could have been changes.  Peter Wigglesworth is likely to know, of course.

Ian Cornish

[rcreweread]

When I stripped down my very original TR4a many years ago and a also rebuilt my TR4, they both had large holes in the original hardboard tunnel covers for a rubber bung to enable greasing of the front propshaft UJ  - see photos so they definitely exist! I have 4 of these and they all have the holes. 

Cheers Rich

[John Mellor]

Hi all, never drilled fibreglass: apart from eye protection and a mask any tips for drilling for gearbox access grommets

[Nigel C]

if you can use a tank cutter the right dia that would be really good, if you only have a drill bit the right size then so be it.

Try and fit a block of wood behind where you're going to drill/cut to support it, if you can't hold the wood in place screw through the grp into it and then fill the holes afterwards.

vacuum cleaner close to the area too and go steady

[ianc]

The material at the point were one needs to cut a hole for access to the gearbox filler is quite thin, so no special precautions required and takes almost no time at all.

I have a tool, acquired many years ago, which is similar  to the 500584 hole saw from Wickes, which has a variety of sizes, including 57mm, which is 2.25".

Ian Cornish

[John Mellor]

Thanks Ian and Nigel. 

Ian, sent you a message

[james christie]

Some gaffa tape, stuck on both sides, catches the bits…

james