overdrive gearbox lid/remote linkage

[Fizzy]

i got an OD box from chic doig, d type, and am still slowly getting the bits together for a conversion. however i didnt realise that the remote linkage or something is slightly different, i think the bar that pokes out the end of the housing is longer or something, to fit the inhibitor cam on ? im not really sure. looking at the one on my box, from memory i cant say it looks any different to the one on my non od box. i'll get a photo later on, but is there anything i can look for to see if its the right one ? what exactly is the difference ? to be honest im not entirely sure how the whole inhibitor system goes together/works.

also, is this the correct relay for the OD ?

http://cgi.ebay.co.uk/Lucas-6-RA-24v-Relay-/170659961730?pt=UK_CarsParts_Vehicles_CommercialVehicleParts_SM&hash=item27bc205b82

[Richard B]

Hi Jason.

Thats not the correct relay as it is a 24volt one you want a 12volt although they look the same. However you can use the more modern relays if you want.


This is the MkIII Spitfire version of the linkage. look at parts 11, 46 & 43

I 'borrowed' the drawings from CC and I think its they are from the parts catalogues.

11 closes the switch 43 when the gearbox is in 3rd and 4th. the other side of the linkage is for the reversing lights.

[Richard B]

Here is the MkIV Spitfire version 158002 & 158072. The switch is not shown but it goes in the bracket same as the MkIII version.

[Fizzy]

thanks. the relay auction, in the title it says 24v, but in the description it says 12v, so ive emailed him to confirm. if its 12v, its right though yeah ?


so in the mk3 diagram, the inhibitor cam (11) slides over the end of the linkage bar that pokes out the end of the remote cover ? and it looks like there should be a hole that a locating pin slots into?  its this bit that im unsure of on my top cover i got with the box.

the bracket (46), uses the bolts that bolt the lid down to attatch ? can the later style bracket be used the inhibitor cam (11) ? ive already got the cam, so need to be using it.

if anybody has a photo that would be relevant of the top of an OD box, i would be most appreciative.

and you say the inhibitor cam also works the reverse lights ? i thought it would stay at the switch i have at the back of the gearbox, directly under the gearstick ?

cheers.

[Fizzy]

right, heres a photo of what ive got together so far



my spit has the 4.11 diff, so i think all the flange bolts are all the smaller size of the 2 types ? the propshaft (which was donated and greatly appreciated), i cant remember what was on it now im at the pc, but with the loose end pictured, i think its ready to fit between the car and the new box. however, when looking at the back of the box, i noticed the flange has 8 holes drilled. is this normal ? im assuming so that both flange types could be used. the UJ's on the car are probably much newer than the ones in the prop, and if its worth it i will probably swap my newer ones on, if thats what the extra holes are for in the box flange.



with the bits in the picture, i also have another reverse/inhibitor switch thats on the car at the moment. ive arranged to buy a mounting plate and half the wiring loom, hoping to make the rest myself. hopefully the relay i linked to will be right, then ive just got to find a bracket. then i think thats it ?

unless ive forgotten something ? ive got to cut the tunnel back aswell i think, just to where the UJ's new position is ?

the linkage bar upon closer inspection IS the right one, huge relief. i see now where the cam goes on, and the pin goes through.

is there a way to test the OD clicks in, or the solenoid, on the bench ? does the OD unit take gearbox oil ?

[Richard B]

Yes you have to cut the transmission tunnel back (about 5"). There's a U shaped plate to cover the hole, easy to make, held in by 3 self tapppers.

Re the 8 holes, yes looks like its for both. Someones DIY, hope they are in the correct places.

The O/D uses the gearbox oil. No separate filler, but the volume is larger with an O/D.

Looks like you are getting there. Do you have the mounting plate beteen the chassis rails?

You can test the solenoid on the bench, hook up 12v feed to the wire and earth the casing and the solenoid 'should' click

[Fizzy]

yes got a mounting plate sorted, thanks.

which modern relay can i use instead ? ive never brought a relay, but they seem quite expensive, and the one i linked to on ebay is 24v unfortunately. would a modern one just be a straight swap in ? wiring isnt my forte.

you mentioned reverse lights further up, im still not sure where these come in, if not in the usual hole under the gearstick.

[Richard B]

Relay http://www.vehicle-wiring-products.eu/VWP-onlinestore/relays/relays.php  I use R20B

Pinouts

30 Power feed in from battery  (Ideally wants to be fused)
87 Power out to Solenoid
85 Power feed in from ignition switch    (so the Overdrive only works when the ignition is on)
86 Wire to O/D switch on column and then to inhibitor switch and then to earth


Socket  http://www.vehicle-wiring-products.eu/VWP-onlinestore/relays/sockets.php  I normally use RS1 but you could use RS3F with which will allow a fuse to be installed.  You don't have to use a socket but it makes it neater and easier to swap out the relay.

Does your car have reversing lights already (it should  :-/ ). The wires should drop into the transmission tunnel near the coil & starter solenoid. Theres a pair of wires one should be green one green (& black I think). This is the best place to feed in the O/D wires. are you using the column switch or a gearstick switch?

[Fizzy]

Thanks for the links. Yes i have the green and black wire going to my current reverse switch. So that switch will be redundant when the relay is in then?

im using a column switch

[Richard B]

No, The reversing light switch is a spearate switch to the O/D inhibitor swtich.

On a D'Type they are two totally different circuits.


Which bracket/linkage have you got? If its the MkIV type then you have one switch on either side of the U shaped bracket.

[Fizzy]

ahh i see. i dont have the bracket yet, one of the last bits i need to get. so the inhibitor cam ive got, that goes on the linkage shaft, is made to be used with the later bracket, which will hold a switch in each side ?

is the same cam used for both types of bracket then ?

apologies, im getting quite confused by this reverse switch business. i was under the impression the cam i had was the early type (as in the diagram you posted from CC) and therfor would need the bracket from the same diagram, which only holds one switch, thus needing to keep the reverse switch i currently have at the back of the box.

but unless im wrong, you're saying the cam i have can be used with the later type bracket to activate the inhibitor and the reverse switches ?

[Richard B]

Going on the cam in your photograph it looks like it has two arms, one for each switch. If you get the bracket for that cam then you can do both functions.

Alternatively if you have a reversing light switch somewhere else and you are happy with it; leave it alone.

[Fizzy]

yes i have the standard reverse light switch which goes in the top of the lid underneath the remote linkage cover. ive got to get a bracket anyway, and i think ive already seen the double sided one for sale somewhere, so will go for that i think. thanks again.

[Fizzy]

solenoid clicks, which is good news. am i right in thinking with no oil in the box it wont actually affect the drive ? spinning the input shaft, and clicking the solenoid on, it made no change to the drive coming out the back, but theres no oil in the box.

heres something i noticed, not something ive seen before. please tell me this is normal, or at least isnt a problem. i dont want to take the gearbox apart, everytime i try it i end up worse off than i was in the first place.



looks like a shim or something. it wont budge either, and is obviously off centre. its not in the other 2 gearboxes ive had int he car.

[thescrapman]

It's teh oil flinger, I have had totally mullered ones on the 2 boxes I have dismantled and rebuilt. Worn to a small disc.

Bothe were slightly off centre as well interestingly.

should be held central by the input shaft being pressed against the bearing. I suspect if there is teh slightest gap it can move about.

Cheers

Colin

[Fizzy]

can i leave it where it is without trouble ? at least for the short term ? were they on all boxes. as mentioned, ive been inside 2 and never seen one before.

[Richard B]

O/D works on oil preasure  (Lots!)