Anyone who is coinsidering laying down the $2,000+ for the GV overdrive might want to do so quickly. They posted a banner on their site that states on March 22nd, the prices will increase $200-$300. They also appear to have a long backlog. I ordered me one on March 2 and still have not recieved it as of March 20.

 

Personally I would have gone with US Gears, from what I hear, it is a lot easier to shift on the fly and at any speed and RPM. Although I haven't heard a lot about Gear Vendors.

 

The problem with US Gears V2OD is that it only works in Automatics. If I had the money, I would buy Gear Vendors Overdrive in a heartbeat.


Matt
1974 F-250 4x4 Highboy

 

 

I went with the US Gear v2od unit. I liked the 30% reduction option and their customer service. I now offer the product on my site and I am trying to add as much information about the swap as I can find.<! <!Boston RPM . US gear is running a sale until the end of may 2008. This would be a great time to purchase the unit after doing your research and price shopping

 

The V2OD units are available in 20 and 30% reductions. The Gear Vendors units are 22%, i believe. The V2OD, requires a manual activation at 30-40 mpg, which lowers the RPMs. The gear vendors unit uses an electronic activation.

 

The shift can be performed by a cable or a lokar shifter. The cable performs the best, I have been told. This cable shift is similar to the overdrive that came in my 53 plymouth

 

you got it. I am going to run the unit behind a built-up C4. i purchased a 351M C4 from a 78 thunderbird for the build. I sold the bellhousing on Ebay to cover the cost of the tranny. The 351m bellhousing allows you to bolt up a C4 to a ford big block. Some people are going with the C4's, over the C6s, due to their size, weight and reduced operating effort. This wouldn't be useful for big trucks, or towing applications however. I hope to get pictures up on the site of the build, when finished. Good luck on your project. You also might want to read about US Gear's dual range transmission

 

Interesting... I never considered the V20D, but that 30% OD sounds nice. I was considering a TKO swap because the 22% OD with GV wouldn't give me a wide enough gear range with my C4. That whole shifting at 30-40 mph sounds a little annoying though... Can I shift into OD at any speed below 40, or does it have to be within that 30-40 mph range?

And how does that affect the C4's shifting? Let's say I'm going to take off at a stop light, pedel to the floor, but would eventually reach 70 mph and want to be in OD at that time. Would I punch it off the line, and make my first shift by putting the V20D into OD at 30-40 mph? Would my C4 not shift into 2nd until later, or would there be a chance of shifting into OD and then the C4 shifting into 2nd seconds later, giving me a huge RPM drop?

I don't race or anything, but my truck is my toy. I like to be able to take off but then cruise nicely once I get up to speed.

 

The V2OD would lower your RPM's by a certain % (20 - 30) at any speed or gear when engaged. You can leave the unit engaged at all times or shift in at any speed below 40. It would be beneficial to not engage it in stop and go traffic or launching from the line. You are going to want to let your rear gears do the work during acceleration from stop when the engine has mechanical advantage.
Here is what I wrote about overdrive on my site:
<!<!Boston RPM

Overdrive Benefits
An overdrive transmission is perhaps the greatest improvement for vehicles equipped with a three speed automatic. The benefits can instantly be felt in the driver's seat and at the pump. This unit can actually increase performance and fuel economy. Other benefits include decreases in engine wear, emissions, and operating noise.
For three speed automatics the engine turns faster than the driveshaft. At this point, the engine has mechanical advantage because the engine does not have to work as hard to spin the tires. At highway speed, the automatic is operating in final drive (third gear) at a 1 to 1 ratio. If your rear axle ratio is 3.5, the driveshaft rotates three and a half times for every axle revolution. At this speed, less power is needed to propel the car. A tall geared car (4, 4.11, etc.) , optimum for launching from a scamaro, will be laboring at highway speeds. A 2.8 ratio, will have poor acceleration and fuel economy in the city, but will offer a higher camaro speed and increased gas mileage at cruising speeds. An overdrive unit engages an additional gear designed to allow the engine to operate at a lower RPM , optimum at highway speeds where less power is needed, while allowing the stock rear axle to be tuned for city driving. This allows the transmission to perform at peak performance at any speed.

 

Gear vendors units allow you to shift into overdrives automatically.
It is important to note that you probably would not have to shift out of V2OD overdrive until you came to a stop, meaning you wouldn't necessarily have to worry about shifting in and out all the time. If you left the OD engaged, it would just operate as if you had shorter rear gears.

 

So are you saying that I can either drive like a normal person off the line, shift into OD before 40 mph and be able to cruise at highway speeds w/ low rpms.... or I can launch off the line, miss the 40 mph window to shift into OD, and then have to rev at 3000+ rpms at highway speeds?

 

Sadly US Gear offers no solution for our era 4X4s, 30% OD would be a blessing on the highway.

 

You might want to call US Gear to confirm. I am not sure what their take would be on shifting under hard acceleration.


I think this is most useful when you know you are going to be hitting cruising / highway speeds. If I was drag racing light to light, I probably wouldn't engage it. I went with the unit because my car was screaming on the highway at 70 MPH. The unit definately allows you to run tall rear gears, perfect for drag, that would normally kill performance at highway speeds.

 

In answer to the question about older 4x4's, US Gear offers the dual range transmission for manual and automatics. I really don't know much about it, but here is what they have on the site as far as overdrive:

What is the ratio of the Dual Range?
The Dual Range is available in two different models: Direct and 20% Overdrive or Direct and 20% Underdrive. The 20% overdrive ratio is .80 and the 20% underdrive ratio is 1.25.

How does the Dual Range work?
The Dual Range works exactly like an electric 2-speed axle commonly found in commercial trucks. The Dual Range bolts directly to the back of your factory transmission giving you the equivalent of two axle ratios or twice the transmission ratios (gear splitting). At the flip of a switch, you can select a high speed ratio for highway cruising or solo driving, or you can select a low range for highway towing, city driving, or mountain terrain. Shifting back and forth from high range to low range can be done at any speed (shift-on-the-fly).