Laycock OD oil and level

G

gvgehrig

Junior Member
Newbie question:

I have a Laycock J type OD. From the threads, I should use 30W oil if it's old type; ATF if it's new type. (1) So how do I tell if it's old or new? Will ATF work either way? (2) There is no plug on the side. How do I put fluid in it? (3) How high should the level be on the visible tube?

I got the car last week. It was delivered with the OD engaged. It was backed out of truck in reverse, and I backed it up a couple of times, maybe a total of 40 feet before I learned that was not allowed. It does not appear to have a safety circuit for reverse. When driving down the road, it will engage the OD, but sluggishly, like it's an oil problem. Any comments would be helpful. Thanks so much.
 

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Hi, I have a Laycock like yours only a little older, on mine, I have a drain plug in that lower plate shown in your pix. Your lower plate has the boss for the drain plug but was not drilled and tapped for the plug.
To drain the oil, you will have to remove that plate try not to destroy the gasket. To fill, disconnect the plastic sight tube at the top and use that as your fill port. He takes 1 quart of oil, I use 10W-40, you can use that or ATF if you like mine worked better with 10W-40 than AFT when it got hot in CA. After you reinstall the sight tube, mark the tube with a marker to indicate oil level.
Mine has a I fill plug on the side 3/8" 0r 1/2" pipe plug.
mine was built by Rich Little in Bakersfield CA.
Post if you have more questions.
Good luck with yours.
 
This overdrive was fitted to Volvos and some British cars . The transmission had an electric switch linked to the shifter which took the overdrive out of gear when you went into reverse .When fitted to a model A torque tube you have to fit a switch linked to the trans top so you cannot be in overdrive and reverse at the same time .Sounds like your A relied on the driver to make sure that the overdrive was "out" when engaging reverse . Not a good idea as you are bound to forget .I suspect the OD is damaged as they cannot be driven backwards .

John still in Suffolk County England .
 
I have one in my 1958 Austin Healey 100-6. It takes 30 wt ND oil. I fill thru the dipstick hole on the right side on top. Not sure about a drain plug location as I have not had to drain it.
 
Hi, when I used ATF on a hot day 95 plus, it would not stay engaged, it would slip back to direct drive. That's when I switched to 10W-40 oil.
I forgot to add that you should have a switch somewhere that controls power to a solenoid on the overdrive. In your pix, you can just see the solenoid on the far side of the O/D just behind the lower site tube port.
This controls the overdrive operation, like John mentioned.
The solenoid switches oil porting inside the O/D to control when it is in direct drive (no power) or overdrive (power on).
Anytime the drive shaft turns it runs an oil pump which builds up oil pressure and when powered this oil pressure changes flow path to engage a cone clutch with the plantary gearset.
It takes shaft RPM to build enough pressure to engage the gearset.
So you may not have ruined the O/D.
Find the switch and with the motor off you should hear the solenoid click when you turn it on and off.
Take the car for a ride and when you get to 40 mph flip the switch on and you should notice a drop in motor RPM.
Always switch on and off with the motor pulling the car, this way the motor and not the drive train will adsorb the change in RPM.
Enjoy.
 
Thanks, I let you know in a few days. I have it jacked up now. Going through all the systems, checking fluids, brakes, etc. I'm going to replace the OD oil and measure the quart into it so I know it is filled properly. I'll take it out again and do as you suggest. Thanks again.
 
The Laycocks that I have had all worked well with 10-30. They are hydraulically shifted, the solenoid opens or closes a valve. Everything else is hydraulic and Planetary gears. Great units and Rick Little is the guy I did the last two with. I put an interrupter switch on the end of the right gear shift rail housing, operates reverse, on the model A shift tower, All power to the solenoid fed from there so that if I put the ****** in reverse there was no power to keep the OD engaged, even if I forgot to disengage it.
 
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As John Charlton mentioned, if the unit was engaged & driven in reverse, there is a very good chance that the unit is damaged & will need attention.
Like Davey in Danville, I also wired a switch & relay to disengage the OD function anytime reverse is selected.
Mine is a Gear Vendors unit & I use 75/90 gear oil in it
 
Drained the oil -- it had about 2/3 a cup of oil in unit. Put in a quart of ATF. It filled it up a little over half full. Hope that's not too much. Had hoped to test drive and report on how well it worked but when checking brakes I learn the front brakes did not work. Oh well. Will continue to work on it. Thanks for all the help. It really is appreciated.
 
Thanks for the advice. Took it for a drive. With one quart of atf, it shifted in and out like a dream. Now to figure out how to install safety switch.
 
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