Overdrive Gearbox

[UPSCAMPERVAN]

Hi all,
I am going to fit a 4 speed overdrive box to my MK2 camper that is fitted with a 2.5 DI, I have the box and the guy I got it from gave me some of the loom, question is does anybody know how to wire up the overdrive?

Regards Dave

[John Grove]

I'm not sure but I think the wiring diagram is shown in the Haynes manual?

[madmark]

it is a very easy wire up job but it depends if you have the 2 inhibitor swithes on the gearbox, anychance of a photo???????

[manandvan]

in short, it needs a plus 12v to the overdrive solenoid to activate the overdrive condition, via: a fuse, a switch, and an inhibitor to stop it being used when reverse is engaged, using relays is an improvement but not absolutly neccesary i could e-mail a wiring diagram (with relays) for a small fee if you like manandvan@btinternet.com

[UPSCAMPERVAN]

Many thanks for your help guys just got to locate the correct prop now then I will start fitting
Got till the spring to get the camper running sweet but if anybody has a spare they want to sell I would be more than gratefull

regards Dave

[baconsdozen]

Some boxes have two switches,some one.To energise the overdrive a feed is supplied via the ignition switch.Using a multimeter or lest probe you should find that the switch (or switches) are open (no contact) in anything other than 3rd or top.Feeding the solenoid through thsese will ensure the unit can't be engaged in reverse or 1st or 2nd.Engaing in the lower gears might put four nice holes in the bonnet as the pistons go into orbit,engaging overdrive and driving it in reverse will damage it beyond repair.

[manandvan]

re last post, i wouldnt be concerned abou 1st 2nd gear inhibitor as i found being able to go from 2nd to 2nd plus overdrive quite usefull when heavy pulling, use in reverse though will smash the overdrive unit it literally bursts the casing apart.

[kevt]

hi, we're in the process of converting an old ci motorhome into a recovery truck, yeah we know, sacriledge, but only to some anyway the scrapman got it first and chopped the body off but its got a chassis to die for, fully waxoiled and then greased,never been welded and its an '83,but i digress,its got a 4spd with overdrive and always thought they only worked in 3rd and 4th, would be seriously interested in knowing how to get it to work in second as well,be great for pulling,any info welcome, cheers kev..

[madmark]

if you look at the wireing you will see that one solinoid is for reverse to stop in going in and the other is first and second ,join the 2 wires together from the 1 and 2 and you will have overdrive in 1234

[FredTransit]

hi, we're in the process of converting an old ci motorhome into a recovery truck, yeah we know, sacriledge, but only to some anyway the scrapman got it first and chopped the body off but its got a chassis to die for, fully waxoiled and then greased,never been welded and its an '83,but i digress,its got a 4spd with overdrive and always thought they only worked in 3rd and 4th, would be seriously interested in knowing how to get it to work in second as well,be great for pulling,any info welcome, cheers kev..

I don't think that's sacriledge at all, I am thinking of doing that with a camper and a luton body. After all, once the body's had it people won't want it as a camper.

[baconsdozen]

Overdrives aren't designed to take the torque transmitted through the drive train in 1st or 2nd gear.Changing down and over revving the engine is also a real possibity.

[kevt]

hi all, on the subject of O/D units,got one that came out of the garage of a reliant scimitar fan with the 3ltr essex lump,brand new but got wet when garage roof fell in,doesn't turn by hand so dont know if its ok or not,was going to look inside till i looked in an haynes manual for o/d and changed my mind any body know if it might fit a tranny?? kev..

[V8TRANSIT]

what engine are you maching it to? i have a simular overdrive box out of an ambulance which should be the same as the scimitar one? mine has got a 3.0v6 in it and it fits nice even the gearstick is in the same place but you may have to do some slight mods on your prop and drive tunnel depending what engine you have???
also you may need a longer speedo cable? these boxes are faily indestructable like the capri boxes so i wouldent be to concernd about a bit of wet damage it should free up ok mate

hi all, on the subject of O/D units,got one that came out of the garage of a reliant scimitar fan with the 3ltr essex lump,brand new but got wet when garage roof fell in,doesn't turn by hand so dont know if its ok or not,was going to look inside till i looked in an haynes manual for o/d and changed my mind any body know if it might fit a tranny?? kev..

[kevt]

hi, we're doing a conversion on a mk2,its already got a 4spd od box but we wont know if it works till its been fitted, but was curious if it will fit if needed,its a laycock lh type. If its no good to us we'll offer it on here in case it may be of some use to one of you guys, will let you all know in due course,thanks kev..