4L60 / 700R4 Aux Valvebody Complaints & Fixes

    In 1987 GM added a Auxiliary Valvebody to the 700R4 / 4L60 transmission in order to give a much nicer (smoother) engagement when placing the shift lever into drive or overdrive. This accumulator cushions the apply of the forward clutches because some vehicles would bark the tires when dropped into gear or they would chew the splines off of the forward clutches over a period of time. A high idle condition of the motor can cause a very harsh engagement or not letting the motor idle down (A Throttle Body Injected motor would take a few minutes to idle the motor down & some people are always in a hurry & would NOT wait). The problem is now that these Aux units have been out on the road for a while is that the accumulator pin will come out of the housing (pictured below) & dump the forward clutch oil. The car will drive like it has a VERY high stall converter in it if the shift lever is placed into the Overdrive position, barely pulling itself but will drive normal if the shifter is placed into regular drive position. 

 

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The picture below shows 2 auxiliary valvebody's side by side, the pin on the right is moving up out of the bore. If you don't check the height of the pin it will slide past you and cause you and your customer a problem in the very near future. Let's fix it right and with confidence.

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Pictured below is the new Heavy Duty Solid Steel Auxiliary Cover that will hold the pin in place without using any epoxy or welding for good. This makes for a fast, inexpensive & easy fix for what can be a very big problem. All you have to do is make sure the pin is all the way down, then bolt the New Heavy Duty cover in place and it's fixed for good! Email me if you would like to know where & how you can get this cover.

Part # K051 $ 6.95 each plus shipping

 

New Heavy Duty Cover

Take the new steel cover and flip it over (dimples face up) and slide the cover across the end   (as pictured below), if the plate hits the pin, then the pin must be tapped down or pressed down until the cover will slide over the top without hitting the pin. Aux # 3 Photo below shows how to use a steel ruler to check the pin height if you prefer rather than using the new cover.

Aux # 1 Photo Below

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Aux # 2 Photo Below

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Aux # 3 Photo Below

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Inspect the center hole for wear, the steel pin causes the hole to egg shape allowing pressure to leak past. Once the pin is down into place, reassemble the accumulator installing the piston into the bottom then the spring and the new steel cover. Install all 3 bolts and tighten bolts to spec's.

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