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C6 over/underdrive
Posted: March 19, 2009, 6:40 pm
by ICEMAN6166
Posted: March 20, 2009, 12:00 pm
by Bills 66
Ice
The add does not contain enough info. Doug Nash and Gear Vendors made both over and under drives for C6's. Doug Nash parts are hard to come by. Gear Vendors is a expensive unit. Under drive allows you to run a low numerical rear end (2.73) and pull like 4.11s also allows split shifting. 1st low, 1st high ect. Over drive lets you run 4.11s and cruise like 2.73s. Figures are just examples they come in different ratio's. I don't know about switching them from a over drive to a under drive. Used a lot in motor homes. Parts are pricey.
Bill
Posted: March 21, 2009, 9:41 pm
by ICEMAN6166
Posted: March 21, 2009, 10:07 pm
by don morris II
interesting
Posted: March 22, 2009, 12:34 am
by Greg D
DNE - Doug Nash. I can't say I have any experience with one though.
Posted: March 22, 2009, 10:44 am
by 64 f100
NO Bozo's! Leaves all the clowns out, damn. Just when I thought it was safe to be a clown again. Noticed it's made for a four wheel drive, dammit again.
Rich
Posted: March 23, 2009, 12:18 am
by modeleh
Those were developed for the corvettes in the 80s, parts are obsolete for them. They are a solenoid shifted gearbox, with straight cut gears, no planetary. Clunk when shifted. Apparantly quite tough though.
The GearVendors units are nothing more than a Laycock planetary OD, an english design used in all kinds of european cars, often found in volvos in the 60s and 70s. GV makes all kinds of adapters to fit either end of the laycock planetary so you can adapt it to pretty much anything, even closed driveline cars like old Model As have had Laycock ODs fabbed in. I just picked up a used GV setup for my slick but haven't got it in yet. What sold me is that parts are still available for them, and if you go to their website the new ones are warranted for 2 years when installed on an auto. Even if you race with it they say. That's a pretty good claim.
My truck has 4.56s and it will give me the equivalent of 3.55s in OD, so I'm excited to get it installed.
Posted: March 23, 2009, 7:47 pm
by DCarr
Gear Vendors is close by me , if you need anything checked out.
Posted: March 23, 2009, 8:06 pm
by banjopicker66
Brian, that is definitely an early Doug Nash unit. A set of brushes and contacts in the side panel reverse the current to shift in and out of OD.
Remember when I visited, and saw a set of switches I liked? I was going to use them on the DNE unit I had at the time in my Slick with a 352 and C-6.
I took the DNE unit out, I decided I didn't really like it. I don't really recall why, though.
I do remember that the DNE unit sits up too high under the cab to fit without cutting some of the reinforcement cross member on the underside of the cab. I didn't like the way it fit up under there, and getting up under there to troubleshoot it was a real headache.
Seals were not available, and it leaked more than I cared for.
It did work though, and was tough as nails.
You need an adapter to fit the DNE unit to the rear of the C-6. You remove the transmission tailshaft housing, and replace it with the adapter; the DNE slips over the output shaft splines and bolts to the housing adapter.
You shorten the driveshaft accordingly.
In the ad's picture, the right side would bolt to the backside of the transmission.