Hot Rods Laycock de Normanville Model J—-O/D functions

Anyone familiar with this O/D setup/ how it functions/ it is behind a Model A truck with synchronized 39 style Ford trans/does it have 1st low and 1st high and so on for all three speeds of the 39 box for 6 seperate speeds??? There is a solenoid looking apparatus on the back of the setup—-by the way the truck has a 12 volt system!! Only pics I have so far are pretty poor quality. Thanks John from Texas but in Lewes,De. To avoid the terrible hot summers. Thanks fellow HAMB members. Flatheads Forever!! Does the clutch need to be pushed in while changing the O/D to different positions??

 

I put one in a '65 Triumph Herald. I used the transmission from the donor too. The shifter had switches in it that only energize the OD circuit in 3rd & 4th. No 1st or 2nd OD. No clutch to use OD. Just hit the switch and the hydraulics do the shifting. Up or Down. You don't really need to let up either. Your trans probably lacks the low gear lock out/s and OD will work in all gears. I don't know if I would do any full throttle 1stOD shifting. They probably locked out low gear OD for a reason on OEM applications. This is my 2nd car with one. You will love the electric/hydraulic shifts. Mike

 

They came as an option on AMC Gremlins.

 

the Gear Vendors overdrive is built from the same design.

The way it works, there's an oil pump inside, and the pump needs to build pressure before it will shift into OD. So the driveshaft needs to be turning at a significant speed, perhaps 30 mph, before you energize the solenoid.

And if you energize the solenoid when it's in reverse, you'll break it, so make sure that can't happen.

Energize the solenoid, while the car is moving at speed, it doesn't care what gear the transmission is in...it will shift into OD. De energize the solenoid, it will shift out of OD.

 

The basic design can handle a much higher operating pressure than LdN originally intended. That is probably the most important aspect in which the GV unit is different. The torque capacity depends on the operating pressure. All it requires, apparently, is a modification to the internal hydraulic pump's pressure regulating valving. That same valving would regulate an external hydraulic pressure source, should you wish to go there.

Hypothetically it should be possible to operate the unit directly via a linkage instead of the solenoid. That would change the slightly whenever-you're-ready engagement quality to a right-now! engagement quality, like on a manual gearbox. But that would complicate rigging a reverse-lockout feature.

 

They are common in European cars (Jaguar, Volvo, etc). I have one in my Jaguar. Electric solenoid kicks it in and you can do it in every gear, I think

 

Look at Mopar 42 RH/RE & 46 RH/RE's, they had big units, some with 6 pinion planetary. I think this is the source of the GV.

 

You don’t have to use the clutch but a little lift of the throttle is best as you flick the switch, with a bit of practice it becomes seamless. The 1/2 cutout is often bypassed on competition cars and with a switch on the gear lever itself it’s easy to have 8 gears. But in normal use I’ve only ever really used them in top.

 

I don't think so....the source of the GV is that funny sounding British/French name he mentioned.

 

Laycock is the British company that made them originally to a design by Edgar de Normanville who was actually British too. He also invented those circular wizzy things that act as windscreen wipers on some boats.

 

The one in my buddy's Grand Cherokee sure looked like the ones in my MGB & Triumph. Always made me wonder. I think they are Laycock with big pumps and such.

 

Thanks for everyone’s input/now I have a “starting” point to try and learn from—-appreciate the various inputs!!!

 

I have one in my avatar roadster. It was a factory option on 75-77 Pacers, Gremlins, and Hornets. They came attached to a Ford full synchro 3 speed. I took mine and removed all the side shift linkage and added a Jeep T150 top shifter. The original side shift setup had a switch on the 2-3 shift rail that prevented engagement unless the trans was in 3rd gear. All that went away when converted to the Jeep top shifter. I just installed a lighted rocker switch on my dash to turn the solenoid on and off. Works great and the light in the switch reminds me to turn off the o/d solenoid when going into reverse or starting off in 1st. It's been that way since 2009 when I first put the car on the road and has worked flawlessly ever since.