Lenco Transmission Overview

Lenco offers an extensive variety of transmissions. ln general, all Lenco transmissions are a planetary design. Planetary transmissions rely on a central sun gear to provide a 1:1 direct drive ratio once shifted from the launch ratio. In order to achieve an underdrive first gear ratio the LENCO transmission relys on planet gears which rotate around the previously mentioned sun gear. Each sun and planet gearset represents two speeds. Those two speeds are (1) the lower underdrive ratio and (2) the direct'1:1 final lock-up drive ratio.

Each LENCO transmission is thus a two-speed and is housed in its single dedicated case.

We achieve more than two speeds by assembly of multiple cases. For example, a three speed requires two cases, a four-speed requires three cases, a five-speed requires four cases and a six-speed requires five cases. In all instances you will require a LENCO reverse unit to achieve reverse movement. Since each case contains one gearset and provides both underdrive and direct drive, multiple cases provide multiple underdrive ratios.

You must multiply each case's underdrive ratio in order to determine the first gear ratio. In the example of a four-speed, the case nearest the engine would contain a 1.37 ratio planet gear set. The middle case would also contain a 1.37 planet gear set. The rear case a 1.31 ratio gearset. By multiplying these three ratios you come up with a 2.46 first gear ratio. Second gear ratio is 1.80 and third gear is a 1 .31 ratio. Final drive ratio is 1:1.



The 4-speed above shows how to determine drive ratios. Multiply all three gearset ratios to determine the first gear ratio of 2.47:1. Multiply the two rear case gearset ratios to determine the second gear ratio of 1.80:1. The gearset in the third case alone, 1.31:1, determines the third gear ratio. All three units shifted equal final drive ratio of 1:1.


The internal action of a LENCO is such that when the transmission is in first gear the chosen planet gear assembly provides the launch ratio. The planet gears are driven by an encompassrng flng gear. When the transmission is shifted a clutch pack compresses the rotating sun gear assembly to the direct drive central sun gear. Thus a 1:1 ratio is achieved. Each case in succession. with its dedicated underdrive ratio, determines the immediate drive ratio. Once all cases have been shifted the entire transmission assembly is locked in the final 1:1 direct drive ratio.

With the extensive number of ratios we offer it is possible to choose from over 7,000 first gear combinations in the case of a four-speed for example. It is not necessary for the driver to disengage the clutch when shifting from ratio to ratio. All shifting is done with the engine's clutch engaged.


Call our technical department at (909) 673-9080 or email us here with any questions you may have concerning function or applications.




CS1 Standard Design
lntroduced in 1972 as a 2-speed the Standard Design LENCO is our largest and strongest transmission. Most often seen in supercharged alcohol and mega HP nitrous cars the CS1 Standard Design LENCO is also commonly used by Pro Mod machines and blown nitro and alcohol drag boats.

The CS1 Standard Design LENCO is recommended for the most severe applications and is capable of repeatable consistency with a minimum of maintenance. Engineered to handle 3500+ HP the Standard Design LENCO is available with up to 5 speeds and comes in a cast magnesium case. Lever or CO2 shift.

The CS2 ,CS3, and CS4
LENCO racing transmission is a smaller, lighter and more compact version of our CS1 Standard Design. Smaller diameter and shorter length make this transmission a practical choice for use in restricted confines and instances when you have limited distance from the engine to the rear end.


The CS2 handles up to 3000 HP; CS3 and CS4 1800 HP. Both transmissions are available in 2,3, 4 or 5 speeds. Magnesium cases are used for both the CS2, CS3 and CS4.

Competition Eliminator, Super classes, Top Dragster and Pro Stock cars are typical classes where you will find the New Generation LENCO. As with the CS1 Standard Design, the New Generation CS2, CS3 and CS4 can be shifted by lever or our CO2 system.

ST1200 Street Strip
The LENCO ST1200 is the answer for Pro Street and street/strip applications. This transmission can be used to drive your hot rod to work Monday through Friday and then to the dragstrip and the winner's circle on weekends. The ST1200 is the same engineering design as the all-out-race New Generation CS2 but with a couple of minor differences. One variation is that the ST1200 uses budget-friendly 8620 alloy for the gears instead of the more expensive 9310 material.


The ST1200 also utilizes aircraft quality bearings where the pure-race CS2 uses aerospace spec components. The result is LENCO quality and durability at a reasonable "Street Machine" price. Recommended for cars making up to 1200 HP the ST1200 is pure LENCO through and through. Air or lever shift.


The LENCODRIVE is the automatic answer for people who prefer torque converter/automatic transmission applications. A perfect replacement for expensive breakage prone Powerglides, Turbos, C4, C6 style and Torqueflite transmissions the LENCODRIVE is 100% LENCO and will handle 2500 HP with ease.

With a selection of 16 first-gear ratios for the two-speed and hundreds more for three-speeds the LENCODRIVE presents you with the opportunity to dial-in your exact combination. You can add additional cases and gearsets that will result in 3 or 4 speeds. As with all LENCO transmissions a separate reverse unit is employed. Air or lever shift

Boat Transmissions and Boat Clutches
Purpose designed and produced for drag, ski and river boat requirements. Shown with our boat bellhousing. The CS1, CS2, CS3 and CS4 transmissions provide the perfect solution for harnessing the unique HP and torque output of boat engines.

The boat clutch provides gentle engagement and disengagement. This unique clutch is a very popular replacement for clunky V-drive dog style in-out boxes.

Gear Ratio Reducer
The LENCO Gear Reducer is used as a stand-alone unit or in conjunction with our CS1 Standard Design and CS2, CS3 and CS4 New Generation transmissions in order to employ tall rear gears with the advantage of a short launch ratio.

Since the taller ring and pinion have more tooth area contact they are more reliable and less prone to breakage. The LENCO gear reduction unit - with a range of 31% to 56%-helps get you off the starting line. Most popular with Sand Dragsters, Mud racers and Modified pullers.