Project Talladega: 1975 Chevy Laguna S-3 Gets 700-R4 Transmission- Chill Pill

Call us self-centered bigots, but we didn't do it for the polar bears. Granted, we live in an era when burning fossil fuels is as evil as capitalism, but our motives are a bit more self-centered. If our '75 Laguna S-3-aptly dubbed Project Talladega-is to live up to its family hauler mission statement, an ancient three-speed slushbox just won't cut it. Relaxed freeway cruising calls for an overdrive transmission, but with a 525hp 408 small-block in the works for our 4,200-pound behemoth, long-term street durability seemed elusive at best. To help solve our dilemma, we turned to Greg Ducato of Phoenix Transmissions (www.phoenixtrans.com), who set us up with one of his company's top-of-the-line 700-R4s.

In the walk of GM overdrives, those who don't care to fiddle around with costly and complicated computers have two options: the 700-R4 or the 200-4R. Although we were initially leaning toward the leaner 200-4R, Greg quickly altered our errant path. "In my opinion, the 200-4R is best suited to lightweight vehicles producing 400 hp or less," he says. "It's true that Turbo Buick racers have thoroughly abused these transmissions with great success, but after the 400hp mark, they require so many mods that they become very expensive and hard to live with on the street. I don't think there's a single component in a 200-4R in stock trim that's as strong as the 700-R4. The 700-R4 also has a deeper 3.06:1 First gear compared to the 200-4R's 2.74:1 ratio."

Among the multitude of modifications Phoenix performs to turn a standard 700-R4 into one of its PT700R4SX is the installation of a heavy-duty reaction sun shell, a five-pinion rear planetary set, billet Second- and Fourth-gear servos, high-capacity sprags, and high-energy frictions and bands. All this adds up to a 700-R4 that can handle up to 600 hp, and provide thousands of miles of reliable street cruising. While we're all for saving a buck and turning our own wrenches, rebuilding an automatic trans is a tedious affair that's probably best left to an expert. Here's what it takes to build a bulletproof 700-R4.

Case Prep
Phoenix's case preparation procedure is a separate story in itself, and the results are simply stunning. Since the cores used for its 700-R4 builds are anywhere from 15 to 20 years old, each case is first hand cleaned with a brush and solvent. Next comes bead blasting, followed by steam cleaning. Afterward, the case is flat-filed by hand on all mating surfaces to eliminate casting flash before all the boltholes are tapped. The most interesting part of the procedure is the finishing process, in which the case is immersed in a vibratory refinishing machine. Essentially a giant tub filled with 4,000 pounds of ceramic alloy media, a special detergent, and a brightening solution, the machine leaves a brilliant semi-polished finish on the case after the 1.5-hour process is complete. Additionally, the refinishing procedure closes case porosity for improved strength. After another round of steam cleaning, the case is finally ready to anchor the guts of a bulletproof transmission. -Stephen Kim

	By altering the size of the...        read full caption By altering the size of the control orifices in the valvebody plate, Greg customized the shift characteristics of our 700-R4 transmission based on its intended use. Some holes were enlarged while others were necked down or blocked off altogether. Shift timing, shift firmness, and the lubrication properties inside a trans are all regulated through proper oil control, so it's critical to set up the orifices properly.	To further modify internal...        read full caption To further modify internal fluid pressure, stiffer springs were installed in the valvebody. Generally, stiffer springs yield a later shift point. Getting the spring rate just right requires measuring the tension on a scale before installation.
The performance shaft on the...        read full caption The performance shaft on the left is used in all of Phoenix's premium 700-R4 variants. The stock shaft to the right has lube holes that are spaced close in proximity and along the same line, which can lead to breakage in a high-horsepower application.	Phoenix uses a genuine GM...        read full caption Phoenix uses a genuine GM five-pinion reaction carrier in its premium-level transmissions. It not only has an extra pinion gear in comparison to the factory piece, but is also built from more rugged heat-treated steel. Moreover, greater surface area along the internal bearing increases load capacity.	For illustration purposes,...        read full caption For illustration purposes, Greg placed a stock 700-R4 planetary assembly (left) and a 200-4R unit (right) side by side. Since both transmissions have devout followers, we won't proclaim the superiority of one over the other; however, it's tough to ignore the fact that the pinions and axle pins of the 700-R4 are almost twice the size, and that its one-piece casting design appears far stronger than the 200-4R's stamped steel construction.
	After the five-pinion reaction...        read full caption After the five-pinion reaction carrier set was loaded into the case, BorgWarner clutches and steels were placed on top of the low-reverse clutch stack. These are among the most critical components in a performance transmission, as the clutches and steels determine which elements within the planetary gear assembly are held stationary to achieve different gear ratios.	By freewheeling when spun...        read full caption By freewheeling when spun in one direction and locking up when spun in the opposite direction, sprags spline into the reaction carrier assembly and enable smooth gear changes under load. The units fitted onto our 700-R4 (top) feature full-length low-drag springs, a wider reinforced cage design, and bronze contact surfaces for improved lubrication.
	Compared to the factory reaction...        read full caption Compared to the factory reaction sun shell (left), the high-performance unit (right) used by Phoenix is thicker overall for vastly improved strength. The beefier spline area goes a long way in preventing breakage and splitting.	The latest GM five-pinion...        read full caption The latest GM five-pinion input carrier (bottom) features a vastly superior cage design in addition to an extra pinion when compared to the older GM design (top). The new design has an upgraded internal thrust bearing assembly as well, which promotes strength and friction reduction.
The 700-R4 incorporates both...        read full caption The 700-R4 incorporates both an input and reaction planetary set. The reaction unit used by Phoenix (right) significantly reduces drag over the factory piece (left) to minimize parasitic power loss. Cutting friction here is critical, as the planetary gears turn far greater rpm than the engine. The reaction hub's heat-treated splines also resist twisting and breakage behind high-horsepower engines.	Prior to installing the pump...        read full caption Prior to installing the pump cover bushing, the mating surface was knurled with a screwdriver before adding a dab of Loctite. These measures promote adhesion and prevent the bushing from walking under high-rpm loads.
GM has used three different...        read full caption GM has used three different pump rotor designs in its overdrive transmissions since 1981. Phoenix prefers the 10-vane unit (left) for its strength and the dividends it offers in pump stability. The sheer number of slots in the 13-vane rotor (right) results in an inherently weaker design, particularly when line pressure is increased for firmer shifts. The primary drawback of the seven-vane rotor (bottom) is its inability to sustain stable pump pressure.	Among the numerous modifications...        read full caption Among the numerous modifications Phoenix made to the pump body was the installation of billet steel pump rings, Torrington vanes, high-capacity boost valves, and a high-performance pump slide and springs. This results in increased pressure output and stable pump operation even at 7,000 rpm.	The spline contact area of...        read full caption The spline contact area of the drums often breaks under heavy stress. Installing a billet steel reinforcement sleeve helps to fortify the spline dramatically.
Compared to the cast factory...        read full caption Compared to the cast factory clutch piston (top), the billet piece (bottom) used by Phoenix is a much stronger alternative. Note the increased tang dimensions and crack-resisting radius of the billet piston.	With the drums loaded into...        read full caption With the drums loaded into the pump, the clutch packs were checked during assembly for clearance, sealing ability, and positive engagement. The blowgun simulates the hydraulic pressure the trans will experience in the car, and reveals any leaks that may be present.	Since input clutch drums are...        read full caption Since input clutch drums are laser welded during the manufacturing process, even brand-new units are often warped. As is evident on this well-worn Reverse drum (left), an uneven surface results in reduced surface area for the band to clamp around. Machining .010 inch off of its drums (right) yields a perfectly smooth band apply surface that's concentric to the center of the drum.
The stock clutch pack uses...        read full caption The stock clutch pack uses steels in between each friction disc. The Raybestos Z-pack 3-4 clutch pack (bottom), on the other hand, features discs that only have friction material on one side. This eliminates the need to run a steel between each friction disc, which reduces heat retention and warping. The greater number of frictions improves the clamping force as well.	After loading in the 3-4 clutch...        read full caption After loading in the 3-4 clutch pack, Greg installed the Reverse drum before sliding in the band and bolting down the pump. He prefers using cadmium-plated hardware on all external surfaces to prevent corrosion. Next, final shaft endplay was set at .025- to .030-inch.	The band anchor pin on the...        read full caption The band anchor pin on the left is used in all Phoenix's overdrive transmissions. Since the stock piece (right) is prone to shearing off right at the seam, this design flaw has been eliminated in the aftermarket pin.
Here is the billet Second...        read full caption Here is the billet Second gear apply piston used in our rebuild (right) sitting next to the Corvette servo (center) and the stock unit (left). The section around the center of the piston is the apply area, and the billet unit boasts significantly greater surface area than either the Corvette or stock piece.	A heavy car like our '75 Laguna...        read full caption A heavy car like our '75 Laguna places a tremendous load on the trans during freeway cruising, a condition that's exacerbated by a high-torque motor. Since the trans doesn't have much line pressure to work with under light-throttle cruising, Phoenix installed this billet dual-stage Fourth-gear apply piston assembly (left). It has nearly twice the apply area of the stock servo.	This custom fixture is used...        read full caption This custom fixture is used to measure band clearance for proper set up of the servo assembly and band apply pin. Improperly setting band clearance-which is a very common mistake-can lead to premature band wear and failure.
In a non-electronically controlled...        read full caption In a non-electronically controlled transmission like the 700-R4, shift point rpm is adjusted by altering the weights and springs in the governor. The lighter the weights, the later the shift point. Based on the projected output and power curve of the 408 small-block that will power Project Talladega, shifts points were set at approximately 5,500 rpm at WOT.	With the transmission inverted,...        read full caption With the transmission inverted, the separator plate, gasket, and auxiliary valvebody were positioned in place. Next, Greg tweaked the spring tension in the accumulator to further fine-tune shift quality. The goal is to produce streetable shifts under light throttle that increase in firmness under harder acceleration.	The proper torque spec for...        read full caption The proper torque spec for the valvebody bolts is 150 in-lb, far less than what most would think. Consequently, many novice builders overtighten these bolts, which can result in warpage and valve binding.
The valvebody retaining bolts...        read full caption The valvebody retaining bolts come in more than one length, and mixing up a bolt can cause serious problems. Using too long or too short of a transfer tube bolt can lead to locking out the low-reverse piston, or breaking the case. Phoenix relies on simple color coding to avoid such fiascos.	This wire connects the throttle...        read full caption This wire connects the throttle valve (TV) linkage inside the transmission to the TV cable. TV pressure is critical on GM overdrives, and a bent wire or a binding linkage can create erratic line pressure and shift quality.	Just how does the lockup function...        read full caption Just how does the lockup function work on a non-electronic transmission? In Fourth gear, oil in the valvebody is routed to a pressure switch that sends 12 volts to the lockup solenoid when pressure reaches a predetermined level. The solenoid then strokes a valve in the pump stator, which engages a clutch that locks up the converter. All this happens in a fraction of a second.
After installing the filter...        read full caption After installing the filter and pan gasket, Greg bolted up a brand-new anodized GM pan. All of Phoenix's transmission builds are tested on the transmission dyno prior to shipping. Phoenix backs all of its transmissions with a two-year, 24,000-mile warranty. Our PT700R4SX model retails for $2,800, and a custom torque converter is included in that price.	Phoenix matched our new 700-R4...        read full caption Phoenix matched our new 700-R4 with its custom 245mm converter, which was built in-house. It features a one-piece hub, and an anti-balloon plate for extra strength. For an ideal compromise between acceleration and efficiency, it was set to stall in the 2,800- to 3,000-rpm range.