Dodge 3-Speed Auto

DODGE 3-Speed Automatic Truck/Motorhome

If you are driving a Dodge Truck with a TorqueFlite 727 there is no reason not to get the Gear Vendors Under/Overdrive kit. It will pay for itself in fuel mileage, engine wear, and resale value let alone your daily enjoyment which is substantial. The very first day you drive the truck it is just a whole different vehicle. Lower engine noise from the 28.6% faster gearing. Fuel mileage jumps 22-28% and engine wear is significantly reduced with the same number of rpm’s that currently take you just 500 miles now taking you 650.

Dodge auxiliary transmissions

With the GEAR VENDORS dashswitch in “auto” you will have automatic overdrive just like the vehicle came with a factory overdrive system. The GEAR VENDORS will shift on and off without attention of the drive and can be used while towing up to combined weights of 25,000 lbs. An interactive floorswitch is positioned for the left foot (just like a headlight dimmer) to give manual control at any moment so that your can turn the overdrive on/off for performance and gear splitting while red and green lights in the dash keep you informed on the overdrive operation. Performance while accelerating or climbing grades is greatly improved by the availability of 6 forward ratios (see Final Drive Ratios). With approximately ½ the drop in engine rpm on each gear change and the ability to downshift at ½ gear intervals (much sooner than with the stock only transmission) performance gains of over 40+ horsepower and 60lb ft. of torque are typically minimum, see Final Drive Ratios.

Hot Rod's, '00 Dakota

Most importantly you are getting this horsepower and torque without modification in any way to the engine. Any other way of increasing power (chips, induction, exhaust, fuel) all put stress beyond the original equipment. With the GEAR VENDORS UNDER/OVERDRIVEâ„¢ you get this power because gears are multipliers of torque, plus the engine can be kept in a narrower (better performing) rpm range when power is needed. For this reason, if you do have performance modifications the GEAR VENDORS also helps them work to their maximum potential. No only do you get performance without engine modification but the overdrive will pay for itself in fuel mileage alone. Add to this the savings in wear you get from slowing the engine down, how much nicer and quieter it is in the truck while cruising and you start to understand that it really doesn’t cost anything in the long run to own the Gear Vendors. If and when you decide to trade off the vehicle you will find that a used torqueflite kit on ebay command over 50% of its original cost or take it with you to the new truck by using our factory exchange program.

The GEAR VENDORS UNDER/OVERDRIVEâ„¢ will do more for this vehicle than any Underdrive or Overdrive on the market. You will get all the features normally associated with an underdrive except a gear below first, plus all the economy of overdrive. Because GEAR VENDORS is the only product you can shift under throttle you will have far greater performance and economy. The GEAR VENDORS comes with the best warranties in the industry (2years for noncommercial use) including a 30 day money back guarantee so you know you are going to be happy with everything abut how this kit installs and drives (see Warranty for details). There is no room here to discuss the countless situations where additional gears and torque multiplication help your vehicle perform. Look at the Final Drive Ratios and then call and get one, you will wonder how you ever got along without it.

DODGE 3-Speed Automatic Muscle Car/Street Rod/Restoration

If you own a car with a TorqueFlite 727 or 904 3speed auto – you own one of the best transmissions ever built. We have race teams that use the Gear Vendors behind these transmissions in vehicles that are not even Chrysler based vehicles (the transmissions are that good). By adding the Gear Vendors you get to keep this great trans and add overdrive and performance gear-splitting ratios to it. You will then have a 6 speed Semi-Automatic that is just the best performing, most durable transmission package out there with huge increases in fuel mileage (typically 22-28%) and performance and fun while driving that you have never had in the vehicle.

Gear Vendors reputation is all about performance and handling horsepower reliably. This is why you have seen GEAR VENDORS in 8 second ¼ mile cars in publications like Hot Rod and National Dragster. This is also why all GM Callaway Corvettes with automatics came with a TH400 and GEAR VENDORS instead of the base Corvette 4-speed auto, as did all the newer Jensen Interceptors with a TF727. If you’re running more than 1200 horsepower (and we have customers that are) then talk to us at the factory as there are some hydraulic changes we do for vehicles up to 2000hp.


GEAR VENDORS to any factory overdrive automatic or manual. You will have a dashswitch that allows both manual and automatic operation. With the switch in “auto” the vehicle will act just like it came from the factory with overdrive. The overdrive will kick in at 47mph or whatever the eprom is set for in our electronics and turn back off at slower speeds without attention of the driver. The ratio is .78 to 1 (see Final Drive Ratios). This equates to 28% faster vehicle speed at the same rpm or take your existing rear gear multiplied by .78 (ie 4.10 X .78 = 3.20). In this example a vehicle with a 4.10 behaves just like it had 3.20s when the overdrive is engaged. This is just the right amount of overdrive as any taller would require a lockup converter or create excessive converter slippage. With the .78 to 1 ratio you’re good with any torque converter you choose for high performance street/strip use.

Another awesome feature of the GEAR VENDORS is that you will have a full 6 forward ratios when you switch to manual on the dashswitch. Pull into low, then hit our button (on the shifter or the floor), a red light appears indicating our Auto-Launch circuit – accelerate between 1st (2.45) and 2nd (1.45) and has a whole bunch more torque multiplication than you have ever felt in your car before. With a 3.55 rear for example the torque multiplication in 1st-over is more than 4.56 diff car would have in 2nd – awesome performance gains. After you have revved up in 1st-over then shift to 2nd and turn us off. Then rev back up and hit the button for 2nd-over for the same benefit (that 3.55 example now get a 4.01 gear). Then 3rd and 3rd-over (the 3.55 in 3rd over is turning like it had a 2.77 diff now hence the trademark Under/Overdrive.

Because of all the performance improvements, if you were thinking of going to a stouter rear gear (higher numerically), wait until after you have driven with these new ratios and you may find you are in love with the performance without a ratio change at all. The performance and sound of the motor is tremendous as it goes through 6 full throttle close ratio shifts. You are in each gear ½ the time you are now so the car is not only faster but it also feels and sounds much faster.

With a 2year unlimited horsepower, abuse, or mileage warranty and a 30 day money-back guarantee – you are guaranteed you will be happy with everything about how this kit installs and drives in your muscle car, street rod, or restoration project. See Magazine Articles for some of the baddest mopars of all time that run a Gear Vendors 6 speed.



Gears Under/Overdrive

Find your transmission and rear gear multiplier below. The Final Drive Ratio shows you how many times the engine turns for one complete turn of the tires. This Final Drive number is also your torque multiplier when in that gear. GEAR VENDORS reputation for being the best is because of its sophisticated planetary construction. This means GEAR VENDORS is the only auxiliary intended as a GearSplitter behind automatics and the nicest to work behind both automatics and manuals. You are able to shift half gears that keep the engine in the power. Any auxiliary that requires you to let off the accelerator or is not intended to shift frequently is not going to give you this performance.

There is not room here to cover all the details so call the factory to discussthe full benefits demonstrated on these charts.


Axle Ratio
Trans RatioFinal Drive Ratio


TORQUEFLITE A904 3-SPEED AUTOMATIC (4 and 6 Cylinder Applications)
Axle Ratio
Trans RatioFinal Drive Ratio

Call or e-mail the factory to find out all the options available in your perfomance application. 1-800-999-9555

DODGE 3-Speed Automatic Application Guide