Dodge Manual 4, 5 & 6 Speed Trans


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Does your Dodge and Chrysler need more power to climb hills or tow with heavy loads, plus at the touch of a button taller gearing for cruising down the highway with the lower engine RPM's and improved fuel mileage, see application guide. Our Gear Vendors overdrive for Dodge and Chrysler are available for automatic transmissions using: 727 and 904 3 Speed. Our Dodge and Chrysler overdrive transmission provides 500 to 600 less RPM's plus 20% increase in fuel economy.  You'll need an auxiliary overdrive transmission capable of gear splitting behind your transmission. The toughest built best performing auxiliary overdrive transmission you can buy is the Gear Vendors overdrive from Drivetrain Specialist.


See How It Works, Guaranteed Amazing Performance for Your Dodge


Gears are multipliers of torque and our Ratio Splitting capability allows you to shift to a gear with more mechanical advantage than the next stock gear in automatic transmissions and wide ratio automatics. This also means engine rpm drops about half what it did without the Gear Vendorss and so rpm is sustained - higher torque and rpm on shift = more Horsepower. When shifted into overdrive final gear reducing both rpm and torque to reduce the manufacture of HP when steady cruising to improve fuel mileage and decreases wear on your engine. Two-year warranty rated at 30,000 pounds applications for Dodge and Chrysler, most beneficial when used in commuters, tow vehicles, 5th wheels and Motor homes. Our overdrive kits are very complete and are designed for your specific vehicle, detailed installation instructions are included in kit, and installation is also available. Related to fuel economy, performance, and emissions — Gear Vendorss overdrive units include state of the art electronics circuits that keep your vehicle in the optimum performing gear. Whether you are driving a older non-computer controlled vehicle or a late model with all the latest emissions computers our electronics provide the interface to ensure maximum performance and correct rpm without lugging or over reving in the wrong gear. The OE factory programming remains intact and our processor just makes it aware of the actual ratio 1,000 of times per second. In older vacuum or throttle linkage transmissions the stock governor on the output shaft instantly slows down the moment the overdrive shifts and so automatically moves the shift point in any overdrive gear up by the correct 28.6%. So both electronic and non-electronic automatic transmissions gain a group of features including a passing gear or climbing gear that is automatically available without driver intervention and is at the split between 2nd and 3rd where you really want it. Need more information on how to save gas or diesel fuel?

Gear Vendors's Complete Kits Ensure a Smooth Installation for You


Gear Vendors overdrive Kits are Complete with Adapters Our Gear Vendors overdrives are supplies with specific adaptation kits for each model of transmission model, the kits are completed. By supplying specific extension housings to each model/brand transfer case Gear VendorsS is able to have a better product with gvyoutubesema2008.jpg increased engineering benefit to the final installation. Fact is, when you are in 4X4 there is very little desire to use GearSplitting and overdrive unless you are racing (and we do make the in-between kit for that purpose), it's 2wd where the benefits of overdrive and additional gears are most needed, see YOUTUBE video for more information.  All our kits bolt directly to the rear of the transmission, you can automaticly control the unit or we suggest you flip switch when leaving city limits sign and turn it off when you get to next city limit sign. No additional crossmembers are required and you retain the factory ground clearance instead of moving the transfer case rearward which puts it at or nearer the middle of the wheelbase where ground clearance is most critical. You get all the benefits of the Gear Splitting performance and overdrive economy (see your appropriate transmission under GM/Dodge/Ford 2wd) and the best auxiliary transmission you can buy. 

Call our Overdrive Expert Today and get Free Information!

You get all the benefits of the GearSplitting performance and overdrive economy (see your appropriate transmission under GM/Dodge/Ford 2wd) and the best auxiliary transmission you can buy. Give our overdrive expert a call toll free 800-2161632 he can answer your questions and help you pick correct model for you application, and get free telephone support during installation when you purchase from 

  • You need quality.
  • You'll want reliability.
  • You want performance 22% Overdrive.
  • You want better mileage 20% more fuel economy!.

YOU WANT A Gear Vendors


Bolt on Performance and Power! 

  • Save Fuel
  • Extend Engine Life
  • Save Money
  • 30,000 lbs Capability
Dodge 3 Speed Automatic Truck/Motorhome   Dodge A-727 3 Speed Automatic Final Drive Ratio
Dodge 3 Speed Automatic Performance Car/Street Rod   Dodge 3 Speed Automatic Application Chart & Pricing
    Dodge RAM Horsepower and Torque
Dodge 3 Speed Automatic Truck/Motorhome

With the Gear Vendors dash switch in “auto” you will have automatic overdrive just like the vehicle came with a factory system. The dash switch can either be mounted in our under dash bezel or the custom in dash bezel like the Fleetwood Limited's that came factory with the Gear Vendors. The Gear Vendors will shift in and off without attention of the driver and can be used while towing up to combined weight of 30,000 lbs. An interactive floor switch is positioned for the left foot (just like a headlight dimmer) to give automatic control at any given moment so that you can turn the overdrive on/off for performance and gear splitting. Performance while accelerating or climbing grades is greatly improved by the availability of 6 forward ratios (see final drive ratios page 12). With approximately 1/2 the drop in engine rpm on each gear change and the ability to downshift at 1/2 the intervals (much sooner than with the stock only transmission) performance gains of over 40+ horsepower and 60lb ft. of torque are typically minimum.

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’s beyond the original equipment. With the Gear Vendors UNDER/OVERDRIVE 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. Not 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 22% so that the same rpm's that currently take you only 500 miles will now take you 640 miles.

Most vehicles will experience mileage increase in the 20percent region if driven at the same top speeds as they are without the Gear Vendors.Increased mileage and reduced engine wear is why all vehicles today come with factoryoverdrive

The Gear Vendors UNDER/OVERDRIVE will do more for this vehiclethen any Underdrive or Overdrive on the market. You will get all the features normallyassociated with an underdrive except a gear below first, plus all the economy ofoverdrive. Because our overdrive is the only product you can shift under throttleyou will have far greater performance and economy. This overdrive comes with thebest money back guarantee (see warranty for details). There is not room here to discussevery situation that arises where additional gears and torque multiplication helpyour vehicle perform. Look at the final drive ratio page and then call and get one,you will wonder how y0u ever got along without it.

Dodge 3 Speed Automatic PerformanceCar/Street Rod
At about 2200 dollars (depending on models) the Gear Vendors is Gear Vendor Overdrive Dodge & Chrysler 3 Speed Automatic not the cheapest way for you to get overdrive (a rebuilt wreaking yard 518/618 is probably cheaper) but our overdrive is by far the best way. Horsepower handling is the first issue. A Gear Vendors will handle 1200+ horsepower reliably. This is why you have seen our overdrive in 8 second 1/4 mile cars in publications like Hot Rod and National Dragster.  If you’re running more then 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. Click image to enlarge.


Horsepower aside, there are several other reasons you will prefer a Gear Vendors to any factory overdrive automatic. You will have a dash switch that allows both automatic ad 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 47 mph 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 the final drive ratio charts on page 7). This equates to 28% faster vehicle speed at the same rpm. Or, take your existing rear gear multiplied by .78 (i.e. 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 lock up converter or create excessive converter slippage. With the .78 to 1 ratio you’re good with any torque converter you chose for high performance street/strip use.


Another great feature of the Gear Vendors is that you will have a full 6 forward ratios when you switch to automatic on the dash switch Pull into low, accelerate, then hit our button (on the shifter or the floor), a green light appears indicating overdrive and your in first over which is right between 1st and 2nd . Then shift to 2nd and turn us off. Then rev back up and hit the button for 2nd-over. Then 3rd and 3rd-over. See more information on Gear Splitting in the Drag Racing section. The performance and sound of the motor is tremendous as it goes through 6 full throttle close ratio shifts. You are in each gar 1/2 the time you are now so the car is not only faster but it also feels and sounds much faster.


Check out the unlimited horsepower warranty and the simple installation in the dimensions section. Then order by calling (800) 216-1632


Dodge/Dodge Ram Final Drive Ratios

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

Final Drive Ratio TORQUEFLITE A-727 3-Speed Automatic


Axle Ratio


Rear End Ratio

4.88 4.56 4.1 3.73 3.42 3.08
  Transmission Ratio

Final Drive Ratio

1st 2.45 11.96 11.17 10.05 9.14 8.7 7.55
Over 1.91 9.33 8.71 7.84 7.13 6.79 5.89
2nd 1.45 7.08 6.61 5.95 5.41 5.15 4.47
Over 1.13 5.52 5.16 4.64 4.22 4.02 3.49
3rd 1 4.88 4.56 4.1 3.73 3.42 3.08
Over 0.78 3.81 3.56 3.2 2.91 2.77 2.4

Below you can find links to other overdrive applications: 


Dodge 3 speed Automatic Trans Products 

Dodge Application Guide 2 Wheel Drive 3-Speed Automatic

Part Number





3DFS727A Automatic 3-Speed 727 18" Tailhousing. Replaces 18 1/2" tailhousing. See kit in above photo.  See the kit in above photo. 60's and 70's muscle cars and street rods. $2645.00
3DFS731A Automatic 3-Speed 727 8" Gas Tailhousing. Replaces 8" tailhousing. 60's and 70's muscle cars and street rods. $2645.00
3DFS732A Automatic 3-Speed Shorty. Uses 4x4 output shaft and housing. Off Road racing and short wheel base street rods pre 1950. $2845.00
3DFS904A Automatic 3-Speed 904. Replaces 15" Tailhousing. See kit. 60's and 70's muscle cars and street rods. $2645.00

DODGE/DODGERAM Horsepower and Torque

If you study these performance curves you will see two major benefits of gear splitting.  As an example we'll use the A727 Trans chart with a 5.9 24 valve cummins engine and a 4.10 rear axle.  Gears are multipliers of torque so at 2,000 rpm in2nd over the torque multiplier is 4.64 where without the Gear Vendors you woould get into 1560 rpm in 3rd direct at 4.10.  The difference in engine torque is oly 10lbs-ft.  But the difference in the multiplier is 4.64 vs. 4.10.  That's over 13% more working torque.  See horsepower and torque curves.
At this same moment horsepower at 2,000rpm is 170 insteadof 125 @ 1560 which is over 36% more horsepower with all the reliability of you stockpowerplant. To figure the drop in rpm or torque multiplier from on gear to the nextcalculate as follows: Final Drive Ratio of the gear you are shifting to , divideby the gear you are shifting from, minus 1, times 100. The difference from 1st overto 2nd is ever more dramatic. This is why if you are towing or loaded heavily, thebest way to reliably improve performance is with the GEAR VNDORS UNDER/OVERDRIVE.It’s the same reason the big 18 wheelers have 2 and 3 speed auxiliaries for 10 to15 gears.
We have included a frequently ask questions section that may answer some of your questions, don't see answers you need, just give us a call we will be happy to review your application with you. The following links provide specific application information, performance data that you can expect and the price data for your specific vehicle.