I am trying to find out if this is the same unit as a Gear Vendor over/under drive unit. It looks like one but says "Gear Vendor" no where on it. I really like the idea of transforming my TH400 into a 6 speed, but don't want to throw away money on something I won't be happy with.
Thanks in advance for any and all comments, suggestions, and help.
Thanks, but I have figured out that much. Question is , is Laycock a division of Gear Vendor? or is this a knockoff? Any opinions as to it's quality compared to Gear Vendor unit that does "look" very similar?
That is what I am finding out but the guy that has it said he pulled it out of a motor home, and the drive shaft that was with it was not what I would expect to see on a Spitfire.
Guess I will pass on this and keep looking for the Gear Vendor over/under.
The Laycock De Normanville J type overdrive is fairly weak and was originally used in the TR6. That company licensed the design to Gear Vendors, and they built a much stronger unit. I believe Gear Vendors now owns the license for it.
As a design, the Laycock itself was VERY strong. There were a large quantity of "Americanized" Laycock OD's that were mfg for AMC. The project was essentially abandoned when the Borg Warner T5 made its debut; in an AMC of all things.
Theres a VERY good chance that the early GV units were the abandoned AMC Laycocks.
This design isn't as strong as the BIG warner OD (R11 and R12), but its plenty overkill.
Gear Vendors got their start by buying surplus Laycock-DeNormanville OD unit from AMC when AMC stopped using them. GV made custom adapters for the AMC units. Later, GV acquired the rights to produce the LD unit and made a bit stronger one. The unit itself should be plenty strong, and you say it DID come out of a motorhome. Under normal driving it should be just fine, just don't use OD when drag racing if you intend to use it in a street/strip car. When OD is switched off it should work like a normal auto, but for racing I'd pull the cable and lock it out. Otherwise you switch it on when pulling in gear, then let off the gas and it will shift into OD. Switch off and it will drop out.
The Borg-Warner ODs used a big electric solenoid to engage, the LD unit uses an internal hydraulic pump and solenoid, the electric solenoid in it is just a valve to activate the hydraulic servo. The design of the BW unit meant it couldn't have power to the trans when you dropped out of gear or it put a strain on the planetary gear shafts, eventually causing one to break. The kick-down switch momentarily grounded out the coil so the OD could safely drop out, but only killed engine for a split second. If you straight wired it with just a toggle switch to the solenoid you'd need to use the clutch before powering the solenoid off to kick out of OD. You don't need to do that with the LD (or GV) units, the OD unit itself is designed a bit differently. Here is the wiring diagram from AMC -- note there is no engine shut-off/coil grounding circuit as with the BW OD: http://www.oldcarmanualproject.com/...AMC Technical Service Manual_Page_379_jpg.jpg
Note that it probably isn't practical to use as a "six speed". In theory it works, but in practice using OD with 1st and 2nd is more work than help. 1+OD is about the same as 2nd, and 2+OD is about the same as third. There will only be about a 200 rpm drop between 1+OD and 2nd. Might help with a heavy motorhome pulling a hill, but not much effect in a passenger car. I straight wired a BW OD many years ago and "split shift" it a bit, not worth the effort.
AMC did make a split-**** trans with the BW OD in 63-65 called the "Twin Stick". The two sticks were a three speed floor shifter with the OD in-out cable connected to a second shorter stick to the right of the shifter. Looked a lot like a 4WD setup. The three speed trans had a big gap between 2nd and 3rd so 2+OD could be effectively used. The kick-down button was on top of the shifter. It was shifted 1/2/2+OD/3/3+OD -- effectively a five speed. You couldn't shift it very fast though.
Thanks for your reply, passed on that unit but still would like to go the gear vendor route but haven't found one at a price I can afford. Planning to work on rear end suspension this summer so hopefully while I have it down I can make the transformation.
Again, thanks for the education!
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