Gear Vendors Under/Overdrive
If you study the performance curves below you will see two major benefits of GearSplitting. As an example we’ll use the TH400 or 4L80E trans chart with a Vortec 7.4 (454). Gears are multipliers of torque so at 3,000 rpm in 2nd-over the torque multiplier is 4.73 where without the GEAR VENDORS you would get into 2500rpm in 3rd-direct at 4.10. The difference in engine torque is only 10lbs ft. but the difference in the multiplier 4.73 vs 4.10. That’s over 18% more working torque.
At this same moment horsepower at 3,000rpm is 260 instead of 210 @ 2500 which is over 23% more horsepower with all the reliability of your stock powerplant. To figure the drop in rpm or torque multiplier from on gear to the next calculate as follows: Final Drive Ratio of the gear you are shifting to, divided by the gear you are shifting from, minus 1, times 100. The difference from 1st-over to 2nd is even more dramatic. This is why if you are towing or loaded heavily, the best way to reliably improve performance is with the GEAR VENDORS UNDER/OVERDRIVE™. It’s the same reason the big 18 wheelers have 2 and 3 speed auxiliaries for 10 to 15 or more gears.
l GM 5.7L (LOS) |
 GM 6.2 V-8 (Diesel (LH6) |
 GM 6.5 V-8 Diesel (L65) |
 GM 7.4L (L19) |
 GM 5.7L Vortec (L31) |
 GM 7.4L Vortec (L29) |
GEAR VENDORS provides overdrive product to racing cars and trucks up to 2000hp and trucks towing heavy RVs up to 25,000lbs gcvw. Whether you are trying to move a couple tons up a steep incline or moving just a couple thousand down the track — the fastest way is with the right gearing. Add the benefits of a final overdrive ratio to reduce engine rpm and increase fuel mileage by typically 20-28% and you have a product that is the single biggest innovation you can bolt to your car or truck. With fuel costs high the overdrive can pay for itself in mileage and engine wear reductions. That makes the driving pleasure of overdrive, and performance improvements free — and then the vehicle is also worth more when/if you ever sell it with the GEAR VENDORS. In the long run it just doesn’t cost you anything to own a GEAR VENDORS UNDER/OVERDRIVE™. For an in-depth discussion on which vehicles can expect these mileage gains see our “common questions” section on the web site.
GEAR VENDORS, INC. 1717 North Magnolia Avenue, El Cajon, CA 92020
Toll Free 800-999-9555 • Telephone (619) 562-0060 • Fax (619) 562-1186
