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MG MGB Technical - OD trans swap: What do I need?

Hi All

Read the archives and wonder if some of you that have changed out a standard transmission for a D type overdrive unit in a Mk1 (1967) can give me a list of what I need and what I need to do for the swap?

I purchased a good OD transmission that will be gone through. I know my 67 has the wiring down to the transmision area.

Anyone have a parts list for needed items and instructions?

I read that the crooked shift lever can be used if it is modified. Anyone have a picture or instructions for the modification? (or is it just better to purchase the straight shifter from Moss?)

Other question is drive shaft. I know I need a longer one, but it was unclear in the archives if a later model B shaft will work.

Last, what is a good technical books on this transmission/OD unit.
Bruce Cunha

Bruce,
Let's see here.

It would be a good idea to order the OD harness from British Wiring. You will need an OD switch for the dash which will be mounted to the left of the steering wheel. It is that crooked switch with the escutcheon with the Overdrive in out lettering. The straight flipper toggle switch can be used, just not the correct look. There is a relay and vacuumn switch that is mounted on your firewall just to the left of the heater box and the vac switch is plumbed into the intake manifold for kickdown on accelleration when the od is engaged. I believe the driveshaft is the same as the later ones, but I will have to check the length of mine against another later one.

The straight gear lever is correct for the od tranny and you would probably be better off with it.

I would get a good Bentley manual or even an old Haynes as the Haynes manuals used photographs instead of drawings.

I have a 67 with the optional OD, but the car is disassembled for restoration, it is starting to go back together now.

Good luck,
Mark
Mwhitt

Bruce, I did this conversion a year ago on an early car myself. The parts books list the later driveshaft as correct for early OD cars. Check the parts books and you will see. Also, the vacuum switch is very hard to come by and when they do pop up on Ebay, they are not cheap. I lucked out and got one out of England for 5 pounds along with shipping. That is another story though. You do not have to have it for the OD to operate. Moss, VB, The Roadster Factory all have the extra OD harness. There is not much to it. There is also a relay. The 2 wires that would hook up to the vacuum switch are just left disconnected. The crooked lever will work as is, but the straight is correct. Hope this helps.
Emmanuel Kafant

Bruce,
If you plan on using the vacuum switch and relay you will need two harnesses one for the relay and vacuum switch and one for the gearbox mounted switches. You can check these out at www.Britishwiring.com
Good Luck,Tony
Tony Shoviak

I also did this swap. The crooked lever works fine, looks better in my opinion. The vacum switch is really of no use unless you are in the habit of turning off the overdrive at very high speed: It is a safety device that prevents you from downshifting when you should not.

Good luck finding the crooked switch for the ON/OFF switch. Unless someone has started selling one.

Beware, some vendors charge a lot more for "Overdrive" electrical bits than they should. The 1ist and 2nd cutout switch was 50 bucks as an overdrive bit and only 15 as a reverse light switch. Ditto with the relay. There are much better relays on the market now days if you do not mind the modern look.

You will like the results, it transforms the car as far as highway cruising is concerned.

Pete
Pete

Moss has the crooked OD switch. I'm putting a 4 sychro OD into my 67.
Bud

The four sync is another kettle of fish. Much better tranny than the three sync and the syncro first is almost as big an improvement in itself as the overdire benefit. (I am using a four sync non od in the 67 after blowing up two early ODs) The swap is a little more involved as you need to decide if you want to alter the bell-housing or the tunnel. The paths are quite different depending on which way you decide. Either well, the archives will answer all of your questions.

Pete
Pete

This thread was discussed between 01/05/2006 and 03/05/2006

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