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MG MGB Technical - Correct gearstick for LH OD gearbox?

Has anyone a pic of the correct gearstick for a LH Laycock OD gearbox

( it turns out that my earlier thread was in error as the name/coverplate was defaced and the box IS an LH)

Would also appreciate any leads in acquiring a loom, a gear stick, gearstick hold down plate , switching , ANYTHING, as all I have is a bare gearbox .

Thanks

Mark
Mark Thompson

Where are you going to fit the o/d switch? The stick mounted switch uses a different stick. I've got both sticks and both hold-down plates, so just let me know which one you need to see.
You can buy the peripheral bits from Moss and most of the usual suspects.
Richard Coombs

Mark. Your model overdrive gearbox was used on the rubber bumper model cars. There are three basic differences between your gearbox and the earlier four syncro gearboxes:

First, there is a filler plug on the right hand side of the gearbox rather than a dipstick through a filler hole on the top, right hand side of the gearbox.

Second, the later models only had overdrive available in fourth gear while the earlier model had it available on third and fourth gears.

Third, the gear shift lever was different, being a two piece unit bonded together with a rubber insert. This later model lever had a slot cut for the pivot bolt on only one side (vice the two sides of the earlier model) and, as a result, used a gearshift hold down plate having a slot cut into one side so that it could be slid in place rather than coming over the top of the gearshift lever.

However, the earlier model gearshift lever will fit into your later model transmission (but not vice versa) and either model gearshift hold down plate will work with the earlier model gearshift lever. Only the correct, slotted, hold down plate will work with the later model lever.

The switch on the left hand side of the upper part of the transmission is the Transmission Controlled Spark Advance (TCSA) switch which, also, functions as the overdrive inhibit switch.

I use a switch mounted on the dash to engage the overdrive. A wire runs from the white wire circuit, through an inline fuse, to the dash switch, thence to the overdrive inhibit switch, thence to the overdrive solenoid. Very easy to make up this circuit using regular wire of 12 to 16 gauge.

Hope this helps.

Les
Les Bengtson

Thanks Les and Richard

Given the info from Richard, I guess pix of BOTH and the appropriate plates would help as I attempt to track either as options, given that I dont have a stick.

I have noted that I will need to "panelbeat" a section of the tunnel and source the appropriate fly wheel, backplate etc.

As with most things MG, it starts out simple and gets.............interesting!

Mark
Mark Thompson

Mark, not sure why Les thought your o/d was from a rubber bumper B as the LH was available from '67 -'74, with black ident cover, and '74 on with blue ident cover. However it makes no difference to the gear stick.
I've attached a picture of both which are pretty obviously for 'stick' switch or 'somewhere else' switch. As Les pointed out the hold down plates are different but the one with the slot will work with both. Again, it's all obvious from the picture.
Prior to the rebuild I ran our car with both and very much liked the stick switch. However my wife, who is actually the registered owner, disagrees so we have compromised by me putting it where she wants it! All you married guys will understand perfectly.

Richard Coombs

The earlier one piece stick can be used on the '75 and later transmissions be simply removing the locating pin, on the left hand side of the shift tower, and replacing it with a short block off bolt. RAY
rjm RAY

As Richard points out their are two types of overdrive box so if you have the rubber bumper blue ident version you will also need to change your speedo to match it.
In the uk they are as follows
62 - 64 = 1020,1040,1060 tpm
65 -74 1/2 = 1280 tpm
75 - 80 = 1000 tpm
You need to look at your speedo and see what number is printed on the face by the trip or odometer.
If you do put a blue rubber bumper overdrive in your car and your speedo is the 4 inch size you will either need to get yours recalibrated or source a 62 to 64 speedo to keep the speedo reading correctly.
Sorry if the australian speedo ratios are different but it is important if you have a late box.
With you saying you need to panel beat the tunnel and alter the hole i am presuming you have a 3 synchro up to 67 car.
Any back plate and flywheel from 68 onwards will fit your box but you also need to source a starter motor and alter your wiring as well.

Ste
Ste Brown

One thing to consider if you don't have an overdrive gearstick is the switch base. These are hard to find and most catalogs show them as N/A. If one shows up in ebay in the states they have gone for upwards of $100. I got an entire stick from the UK for a lot less including shipping.
An alternative might be the windshield wiper/overdrive switch.
E Emery

This thread was discussed between 24/09/2011 and 28/09/2011

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