High performance, heavy duty and even light duty 700's have been known to experience premature 3-4 clutch failure or distress. Installing a heavier pressure regulator valve spring only and ignoring these two boost systems could lead to sup standard performacne and many hours of rework so why not Fix It Right The First Time! 3-4 Clutch Pack Be sure to caution your customer! Having him or her sign a waiver or disclaimer ont he repair order might be a good idea. Given the right road conditions, this can cause loss of vehicle control.
297 inch setup will keep the unit in first with the selector in manual one right up to floating the valves, however, at moderately higher speed, the unit will go into first if the selector is pulled into manual one after an upshift to second or third gear.īe careful and thoughtfull here. IMPORTANT TECH NOTE: On most high-rev applications, an upshift to second can occur even though the selector is in manual one. 422 inch boost valve and bushing is available under part number 8634941, the. For big blocks or highly modified small blocks, use the. 433 inch valve is suitable for street and strip cars, trucks, Vettes, and IROC's.
Now check the land opposite the stem end of the TV boost valve. 297 inch valve and bushing is available from GM or your parts distributor under part number 8648959. 297", you very likely will not achieve a short, firm, tire chirping manual 1-2 shift. For the boost systems, begin by checking the size of the intermediate boost valve by measuring the long, smaller land. Most valve body kits will contain a heavier tension spring for the pressure regulator valve, to increase pressure. Okay, let's build this 700 to be a winner! You, the transmission, and whomever the customer is will be a winner too! This way, if a calibration change is needed, you will at least have a reference point. For all installations, we suggest that you follow the instructions carefully. The parts and technical information also coordinate with the separator plate orifice sizes, 2-4 servo pistons, accumulators etc. Valve body kits offer convenience, since most are packaged with parts and data to modify main line pressure, shift scheduling, shift feel and firmness, detent downshifts etc. Although there will be discussion on hydraulic controls, the various high performance, after market valve body kits, work very well whether it's for furnishing very short and firm tire chirping shifts in an IROC-Z, or ferocious shifts in a drag strip 11.52 et runner. I will discuss some of the principal areas for high performance modifications.
I'm sure you remember the first few high performance transmissions? During the mid to late eighties, many performance and durability products had been developed so that the 700 could be successfully repaired in average vehicles as well as for high performance street strip vehicles. The 700 transmission drove the industry crazy with broken pump vane rings, burned 2-4 bands, premature 3-4 clutch failure, sprag failures, planet failures, etc. Remember when the THM 700R4, now more commonly know as the 4L60/E, transmission was introduced in the early eighties.