Anyone running a Gear Vendor or Doug Nash (Now US GEAR) over/underdrive?

[68 Suburban]

I just scored an over/underdrive unit for the turbo 400 in my burb. I was wondering if there is anyone out there that has one of these units on their truck? From what I understand, they are awsume. Nothing like having an available 6 speeds that can pull 30,000 lbs I still have not decided if I am going to use it or not, but I could not pass it up.

[MrGoodpliers]

Wow, if you got it cheap or free, you scored! I checked them out online and-- Get out your checkbook! Whew, they're expensive! I'd love to have one, though, so if you decide not to use it...

[kwmech]

In my opinion the gear vender unit is the better of the 2, have one in my 68 and it works great. Takes my 4.56 gears down to 3.64

[Custom 68]

Hey Chris I had asked that too. Put me in line if you decide not to use it. I would like to try one I am using the 400 also and like to keep it but for the money the 700 is generally cheaper.
Let me know if you decide to get rid of it.
Thanks
Dave

[Custom 68]

Kwmech I had a question and never found anybody using one. How does it work on the shifting between gears? I mean say you are in first in the overdrive side and you go to second does it automatically go back to the low side for second? how quick is the splitting?
Thanks

[68 Suburban]

Originally posted by Custom 68
Kwmech I had a question and never found anybody using one. How does it work on the shifting between gears? I mean say you are in first in the overdrive side and you go to second does it automatically go back to the low side for second? how quick is the splitting?
Thanks

IT is not automatic. It is like driving a truck with a 2 speed rear end. Here is what I was told. Not in my words:

To shift down, from DIR to UD in our case, the driver backs off the gas, pushes the shift button, then taps the gas to take the preload from the driveline, which allows the synchronizer to pop into -place. An upshift is just as painless. When cruising steadily, the driver hits the shift button while accelerating a little, then quickly taps off the gas for a moment to allow the gearbox to make its shift back to DIR drive.

[Mechanic]

I run an American Overdrive behind my TH400 w/4.10 gears and it sure is sweet out on the highway. It's a .7 OD that brings me to around 2.87. So at 60 mph it drops from 2600 to about 1800 RPM. It switches with an electric solenoid...pretty much instant. It does not automatically shift in or out of OD when the trans shifts up or down...you have to do that your self. I really only use it when I'm up to cruising speed to get the RPMs down. This is a BB Cheyenne 20 w/a camper, towing a horse trailer set up. You can get some wicked top speed with one of these in an empty truck with the right gear set.

Frito-Lay used to put these in dually BB delivery trucks years ago. The ones that used to pull the trailers around to stores. You might find one in a wrecking yard out west around WA, OR, and CA. I've seen them in P chassis step vans also. American Overdrive used to be in Redding, CA. but they're no longer in business. One nice thing is the internals are all TH parts. Only the case is custom. Mods needed: remove the tailshaft, and shorten the driveline, and replace the front yoke and UJs. Been in the truck 15 years. Tom

[68 Suburban]

I had the choice of an overdrive or and underdrive unit. Since I have a 3.08 rearend all ready, I decided to go with the 25% underdrive unit. That will make my burb drive like it has a 3.85 rear end until I switch down and my final drive will be the 3.08. This is a much better unit for me since I do a lot of towing in the mountains. I will be able to tow better and still be able to keep my 3.08 rearend gas mileage.

[Custom 68]

So did you buy this new? I would be interested in the overdrive unit since you had your choice. Is there one available? PM me if you have any info.
Thanks
Dave

[68 Suburban]

Dave, no I got it used. What trans do you have in your truck?

[68 Suburban]

Dave, this is a neat little unit that was used back in the late 60's and early 70's on Yenko and Baldwin Motion cars.

http://cgi.ebay.com/ebaymotors/ws/eB...K%3AMEBWA%3AIT

[67Fleetsidedream]

I have a T56 that has an overdrive in 6th of .62. It cost me 4 1/2 hours of install time and $2500.00. I looked at the GV unit and it is WAY over priced. You got a deal if you bought it for less than 3 grand.

[Custom 68]

Thanks Chris. I saw that from your previous post. looks pretty neat honestly I had not heard of them. My tranny is a 400 turbo. I really like it but like the idea of the overdrive. I have 3.73 gears.

67Fleet I agree. They are way overpriced. I wont and cant justify that heafty price. I like most people are looking for a steal of a deal. I would love to have the 6 speed but I also cant justify that cost maybe someday.
Once I get my truck back together I will probably drive it for awhile and decide if it is necessary. I had the 3.08 before the tear down but in the process I ended up with the other gears, for performance this is what I wanted. I am installing a new motor and these gears so we will see what it does when it is all said and done.

[68 Suburban]

Originally posted by 67Fleetsidedream
I have a T56 that has an overdrive in 6th of .62. It cost me 4 1/2 hours of install time and $2500.00. I looked at the GV unit and it is WAY over priced. You got a deal if you bought it for less than 3 grand.

First of all before you say they are way overpriced, you can get a NEW GV overdrive for $2400. Second, they are not designed just for a C-10, C-20, or a C-30 truck. They are designed to work with big Motor Homes and trucks and can handle 35,000 lbs. I don't know to much about the T56 trans, but I am pretty sure it was not designed to haul heavy weights. Besides, I drive my truck to much, and the automatic is soooooo nice

Also, I paid about 1/10 the dollar amount you quoted.

[68 Suburban]

Originally posted by 68 Suburban
First of all before you say they are way overpriced, you can get a NEW GV overdrive for $2400.

http://www.gearvendors.com/prices.html

Second, they are not designed just for a C-10, C-20, or a C-30 truck. They are designed to work with big Motor Homes and trucks and can handle 35,000 lbs. I don't know to much about the T56 trans, but I am pretty sure it was not designed to haul heavy weights. Besides, I drive my truck to much, and the automatic is soooooo nice

Also, I paid about 1/10 the dollar amount you quoted.

[67Fleetsidedream]

They are designed to work with big Motor Homes and trucks and can handle 35,000 lbs.

I wanna see you pull 35,000lbs in your burb. You still got a killer deal on it. I would have jumped all over it.

[68 Suburban]

Originally posted by 67Fleetsidedream
I wanna see you pull 35,000lbs in your burb. You still got a killer deal on it. I would jumped all over it.

With my drum brakes and kevlar showes I can do anything :p