Gear Vendors Overdrive for Ford 4, 5 & 6 spd. manual transmissions


Gear Vendors Save Gas or Diesel Fuel Extend Your Ford's Mileage, Extend Engine Life, Start Saving Money Today!

Does your Ford 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 Vendor overdrive for Ford are available for the following manual transmissions: T10, T-18, T19, ZF-542, ZF547 and the ZF 6-650 6 Speed. Our Ford 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 Vendor overdrive from Drivetrain Specialist.

See How It Works, Guaranteed Amazing Performance for Your Ford

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 manuals. This also means engine rpm drops about half what it did without the Gear Vendors 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 Ford, 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 Vendors 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 Vendor's Complete Kits Ensure a Smooth Installation for You


Gear Vendor 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 VENDORS 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 manually 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 GearSplitting performance and overdrive economy (see your appropriate transmission under GM/Dodge/Ford 2wd) and the best auxiliary transmission you can buy.

Free Technical Support, Get Expert advice about your vehicle's performance with our Gear Vendorss Overdrive. Call toll free at 800-216-1632. More fuel milage 20%, 600 RPM reduction in Engine RPM means longer life and you save Money!

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


  • Save Fuel
  • Extend Engine Life
  • Save Money
  • 30,000 lbs Capability


Ford 4 Speed manual Truck/Motorhome   Ford ZF 5 Speed Manual Final Drive Ratio
Ford 5 Speed manual   Ford 6 Speed Manual Final Drive Ratio
6-Speed Manuals   Ford 4 and 5 Speed Manual Application Chart & Pricing
Ford T18/19 4 Speed Manual Final Drive Ratio   Ford Horsepower and Torque Curves
Ford 4-SpeedManual Transmission Trucks (cars call).

The Borg Warner T18/19 and NP 435 are wide ratio 4-speeds. They have a granny low and so then just 3 normally usable ratios. See the final drive ratios chart and notice the extreme benefit there is to gear splitting by using the Gear Vendors.

You will have an Eaton 2-speed switch on your shift lever to control the Gear Vendors (turning it on/off) while depressing your clutch. The .78 to 1 overdrive ratio will increase you vehicle speed by 28% or reduce engine RPM at a given speed by 22%.


Fuel savings are typically over 20% in both diesel and gas applications. The Overdrive will pay for itself while giving you tremendous performance gains in torque multiplication and horsepower. Read the other sections below, including 5speeds and Common Questions. No competing product can benefit you asmuch as the Gear Vendors so call us and get one on its way to you.

Ford 5-Speed Manuals

Look at the Final Drive Ratiocharts and notice the great benefit in gear splitting withthe Gear Vendors. When you are climbing grades you will have a gear between 2nd/3rd and 3rd/4th that is ideal for keeping the engine in the power and the torque multiplication up. Look at the horsepower and torque curves and notice that by keeping the enginein the power you will gain 50+ horse power and 60+ lb. ft. of torque without any modifications to the engine.

The more heavily you are loaded the more you need the Gear Vendors and when you are heavy you would do best by not using 5th but instead use4th+Gear Vendors (4th over). This will keep your transmission temperature as muchas 100 degrees cooler (extending transmission life) and puts the stress on the Gear Vendors planetary gearing which is much stronger.


When you are running empty (without the aerodynamic load of the trailer) you can use double overdrive (5th over) and enjoy 22% lower rpm and better fuel mileage.  At today’s 75mph highway speeds this is a very nice feature.

Ford 6-Speed Manuals

Look at the Final Drive Ratios chart in this section and notice the benefitsof gear splitting with the six speed transmission. 2nd-over and 3rd-over give yougears that make more torque multiplication than taking the full grab to the nextgear. Also now when you do shift up to 3rd-direct you are going 28% faster so therpm drops nearly half of what it did without the Gear Vendors.

Performance with these shorter steps improves horsepower 50+ and torque 60+ft. lbs. Without modification to the engine the most reliable way to make power (study the Horsepower and Torque curves in this section). Notice that 4th-over and 5th are really duplicates (which is why you don’t feel like you need a gear here).  5th-over however is very useful when the vehicle is heavily loaded.  By running this gear, you will have a slightly higher torque multiplier and the transmission will run as much as 100 degrees cooler than in 6th (which is the weakest gear) so you will only use 6th when empty.  When you are running empty 6th-over (double overdrive) will get you better fuel mileage and far less engine wear at today’s 75mph speed limits. Not only is the engine turning slower but so are all the engine driven accessories which cuts down on parasitic losses and wear to these components (turning the air compressor or alternator slower greatly reduces their work and load on the engine).


For the empty truck which never tows and is never drivenabove 55 or 60 the stock transmission is good, but for everyone else 10 gears willgive great performance gains. Plus this gearing will actually pay for itself manytimes over the life of the vehicle. Even the resale value of your truck will improveby more than the cost of the Gear Vendors because you will be able to point out thatthe engine has seen better care and effectively far less miles than other used trucks.Although we do a tremendous amount of business nationally with customers moving theirGear Vendors from their old truck to their new truck, it’s likely even more economicalto get the added value when you sell and just purchase another Gear Vendors.

If you tow or run at speeds above 70mph there is just nogood reason not to have a Gear Vendors overdrive.

Find you transmission and rear gear multipliers below. The Final Drive Ratio shows you how many times the engine turns for one complete turn of tires. This Final Drive number is also your torque multiplier when in that gear. 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 manuals. You are able to shift half gears that keep the engine in the power band.  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 T-19 4-SPEED MANUAL (Diesel & Gas Final Drive Ratios)
    Axle Ratio     Axle Ratio
   Rear End Ratio 4.1 3.55     4.1 3.73 3.55
  Diesel       Gas      
  Trans Ratio       Trans Ratio      
1st 4.02 16.48 14.27   5.11 20.95 19.06 18.14
2nd 2.41 9.88 8.56   3.03 12.42 11.3 10.76
Over 1.88 7.71 6.68   2.36 9.69 8.8 8.39
3rd 1.41 5.78 5.01   1.79 7.34 6.68 6.35
Over 1.1 4.51 3.91   1.4 5.73 5.22 4.95
4th 1 4.1 3.55   1 4.1 3.73 3.55
Over 0.78 3.2 2.77   0.78 3.2 2.91 2.77


Final Drive Ratio ZF 5-SPEED MANUAL (Diesel & Gas)
   Rear End Ratio

Axle Ratio


Axle Ratio

    5.13 4.1 3.55     4.1 3.55
  Diesel         Gas    
  Transmission Ratio         Transmission Ratio    
1st 4.14 21.24 16.97 14.7   5.72 23.45 20.31
2nd 2.37 12.16 9.72 8.41   2.94 12.05 10.44
Over 1.85 9.48 7.58 6.56   2.29 9.4 8.14
3rd 1.42 7.28 5.82 5.04   1.61 6.6 5.72
Over 1.11 5.68 4.54 3.93   1.26 5.15 4.46
4th 1 5.13 4.1 3.55   1 4.1 3.55
Over 0.78 4 3.2 2.77   0.78 3.2 2.77
5th Overdrive 0.76 3.9 3.12 2.7   0.76 3.12 2.7
Double Over 0.59 3.04 2.43 2.11   0.59 2.43 2.11


Final Drive Ratio M6HD 6-Speed

Axle Ratio

  Rear End Ratio






  Transmission Ratio

Final Drive Ratio

1st 5.79 28.35 24.9 23.74 21.6 20.56
2nd 3.31 16.15 14.23 13.67 12.35 11.75
Over 2.58 12.59 11.09 10.58 9.62 9.16
3rd 2.1 10.25 9.03 8.61 7.83 7.45
Over 1.64 8 7.05 6.72 6.12 5.82
4th 1.31 6.39 5.63 5.37 4.89 4.65
Over 1.03 5.03 4.43 4.22 3.84 3.66
5th 1 4.88 4.3 4.1 3.73 3.55
Over 0.78 3.81 3.35 3.2 2.91 2.77
6th Dodge O/D 0.72 3.51 3.1 2.95 2.69 2.56
Double Over 0.56 2.74 2.42 2.3 2.1  

Ford 4, 5 & 6 Speed Manual Trans Products   


Ford Application Guide 2 Wheel Drive 4, 5 & 6 Speed Manual Transmissions

Part Number




3D0019C T18/T19 4 Speed Manual Transmission Replaces 4.25" tail housing 1980-1987 3/4 and 1 ton Ford pickups.
3D0435A NP 435 4 Speed Manual Transmission Replaces 4.75" tail housing 1967-1979 3/4 and 1 ton Ford pickups.
3D0050 ZF 5 Speed Manual transmission with driveline park brake Replaces tail housing, parking brake moved to the back of overdrive unit, see the kit. 1988 and newer Ford F450 with driveline park brake
3D0172A ZF 6 Speed Manual Transmission 2 wheel drive with OD

Spicer 1350 front & rear fixed yokes, see the kit.

Replaces carrier bearing in 2 piece driveshaft's, or becomes a carrier bearing. Fits all applications except 1990 & newer standard cab w/gas engine.
3D0172C ZF 5/6-Speed Manual Transmission 2-Wheel Drive with Overdrive. Replaces carrier bearing in 2pc. Driveshafts. Spicer 1350 front fixed yoke and Spicer 1350 rear fixed yoke, installation is $200.00 additional, see the kit. Fits all applications except 90' & newer standard cab trucks. Call GV about direct mount option.
3D0063 Ford top loader T&C Replaces 14" tail housing Ford cars 1960-1970's
3D0T11 Ford Borg Warmer T10 Replaces tail housing Ford cars 1960-1970's

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.