By: Bob Ryder
Reprint from Truckin’ Magazine, January 2008
Photography by: Bob Ryder
We have been following along as Bill Markel from Bonfire Racing in Lancaster, California, and Elon Ahal from Van Nuys, California, have been building a custom ’67 Chevy C-10 pickup. In Truckin’ Volume 33, No. 8, Part I, “What it Takes,” introduced us to Nightmare’s foundation of the frame, suspension, brakes, wheels, and tires. Truckin’ Volume 33, No. 9, Part II, “’04 Pontiac LS1 Engine Make Over,” Bill and Elon increased ’67 Nightmares torque, horsepower, and appearance.
In this segment, Bill and Elon will be linking the ’04 Pontiac GTO LS1 horsepower through a GM 4L60E four-speed automatic transmission to the GM 12-bolt rear end. A Gear Vendors 4L60E under/overdrive unit will be bolted up to the 4L60E transforming it into an eight-speed automatic transmission.
For more capacity, Bill substituted the factory transmission fluid pan with a LPW Racing Products cast-aluminum pan, that allowed two more quarts of fluid capacity and features a recessed magnetic drain plug. The Drivelines fabricated a new 44-inch driveshaft, complete with Dana/Spicer yokes and U-joints. The driveshaft was bolted up to the GM 12-bolt rear end that received a fresh Richmond Gear 4/11 ring-and-pinion gear set, pinion yoke, and axle bearings. The factory rear-end cover was upgraded with a stronger LPW Racing Products cast-aluminum cover that allows more fluid capacity and dissipates heat faster for optimum performance.
A B&M Racing Performance Black Diamond carbon-fiber ratchet shifter with carbon-fiber-faced transmission temp and oil-pressure gauges was also added to the drive-train equation.
1. Gear Vendors Under/Overdrive System bolts right up to either a manual or automatic transmission. The unique gear-splitting capabilities of this reaction planetary gears doubles the number of pre-existing forward gear ranges at any throttle position.
2., 3., and 4. Shims were installed to achieve the proper depth of the Gear Vendors coupler that slides over the splines of the GM4L60E output shaft.
5. After removing the factory FM4L60E tailshaft housing, the Gear Vendors tailshaft adapter housing was slid over the transmission’s output shaft.
6. The Gear Vendors tailshaft housing was aligned with the factory GM 4L60E transmission housing.
7. A 1/2-inch closed wrench was used to snug up the bolts, securing the Gear Vendors tailshaft adapter housing to the factory GM4L60E transmission.
8. and 9. To achieve spot-on alignment, the transmission mounting plate was flipped over, then sandwiched between the crossmember and the transmission housing. The nuts were secured using a 1/2-inch wrench.
10. and 11. After lubing the Gear Vendors speedometer adapter O-ring, it was slipped into the GV tailshaft adapter housing and secured using an 8mm wrench.
12. The Gear Vendor main body is stuffed with all new unique designed internal components including: vertex clutch, planetary gear-set, roller clutch, ring gear, fluid filter, and internal pump. Notice the eight long mounting studs that secured the main body.
13. Gear Vendors stout input shaft will be aligned with the Gear Vendors coupler, mating the GM4L60E transmissions output shaft to the Gear Vendors input shaft.
14. The Gear Vendors main body studs were aligned with the tailshaft adapter mounting holes and secured.
15. From above, we can observe the assembled, slender compact Gear Vendor unit with its reinforced rib construction.
16. Currie Inc. installed a set of 4.11 Richmond Ring/Pinion gears and an Auburn posi-unit into the GM 12-bolt rear end.
17. To acquire added strength and aggressive looks, an LPW cast aluminum differential cover was bolted up the GM 12-bolt rear end.
18. The Spicer driveshaft yoke was aligned and slid onto the Gear Vendors output-shaft splines.
19. Yarman Drivelines in Lancaster, California, fabricated the master link, a 44-inch x 3-1/2-inch-diameter .083 wall, DOM driveshaft with Spicer yokes at each end.
20. and 21. After thoroughly coating the Spicer rear U-joint and U-bolts were inserted and the nuts and bolts were then secured.
22. A profile view of the Gear Vendors under/overdrive unit bolted up to the GM 4L60E transforming the four-speed automatic transmission into an eight-speed automatic transmission.
23. The 4L60E eight-speed gears will be engaged with this B&M Racing Performance Black Diamond Composite X ratchet action floor shifter. It features a carbon-fiber console with transmission and water temperature, carbon-fiber face gauges. A comfortable hand-formed carbon-fiber pistol grip features a red reverse lockout button. Gear Vendors supplies a plug and play aluminum case speed control processor.
24. A view from above gives you an idea of the size of the Gear Vendors unit. The GV system input shaft is coupled up to the factory GM 4L60E output shaft.
GM4L60E automatic transmission x 2,
(automatic four-speed = automtic eight-speed + OD).
Gear Vendors Bullet-Proof under/overdrive magic splits the existing gear ratio spread of the transmission. It is designed to shift during any throttle position, either up or down (gear splitting). The Gear Vendors essentially creates a “half-gear,” meaning when the unit is engaged it develops First gear, First Gear over, Second gear, Second over, Third gears, Third over, and Fourth gear, Fourth over; which would be suitable for towing. In other words, the Gear Vendors transforms the GM 4L80 four-speed automatic into an eight-speed automatic transmission with overdrive. When shifted into overdrive, the engine speed is reduced by 22 percent.
The mechanical internal parts of the Gear Vendors under/overdrive compact automatic transmission are constructed of high quality materials withstanding the continuous meshing of gears, planetary gears, clutches, and hardened shafts.
The Gear Vendors under/overdrive system will give you an increased gear selection of eight speeds forward, which will develop more grunt (torque), less wear on internal engine and transmission parts, due to the high rpm.
YOUR QUESTIONS ANSWERED:
Time Spent Working . . . . . . . . . . . . . . . . . . . . 4 Hours
Degree of Difficulty . . . . . . . . . . . . . . . . . . . . Intermediate
Tools Used: Assorted hand wrenches, a pneumatic wrench, a 3/8-inch drive ratchet, and sockets.
PARTS LIST: B&M RACING & PERFORMANCE PRODUCTS
BLACK DIAMOND SHIFTER
PN 81091 Black Diamond with pistol grip shifter . . . . . . . . . $425.00
PN 80331 Smoked lens/LED water temperature . . . . . . . . . $70.00
PN 80330 Smoked lens/LED trans temperature . . . . . . . . . $70.00
GEAR VENDORS INC.
PN3D4L61 GM 4L60E Tow N Go replacement . . . . . . . . . $425.00
LPW Racing Products Inc . . . . . . . . .
PN501-700 GM 4L60E transmission pan . . . . . . . . . $89.99
PN44l Yarman driveshaft 44-inch 3-1/2-inch OD . . . . . . . . . $223.51
PN301-12T LPW aluminum rearend housing cover . . . . . . . . . $167.00
Richmond Gear 4.11 . . . . . . . . . $185.00
Total Cost: . . . . . . . . .
. . . . . . . . . . . . . . . . . $3,825.50
25. The enhanced ’04 Pontiac LS1 powerplant will increase it’s performance, mileage, and emissions after installing the Gear Vendors under/overdrive unit. The GM4L60E, final overdrive ratio will reduce the engine rpm increasing fuel mileage by approximately 20 to 28 percent and reducing the engines emissions by nearly 25 percent.
B & M RACING & PERFORMANCE
9142 INDEPENDENCE AVE.
CHATSWORTH, CA 91311
PO BOX 1000
TOLEDO, OHIO 43697
1717 N. MAGNOLIA AVE.
EL CAJON, CA 92020
LPW RACING PRODUCTS
632 E. MARION ST.
LANCASTER, PA 17602
RICHMOND GEAR HI-PERFORMANCE
1208 OLD NORRIS RD., P.O. BOX 238
LIBERTY, SC 29657
166 WEST AVE.
LANCASTER, CA 93534