Tips for your 700R4 Rebuild

Posted: February 7, 2016 in Automotive
Tags: , ,

If you’re diving into your first 700R4 rebuild (or maybe it’s just been a while), and are looking to verify some of the suggestions from your friends, local mechanics, or even the instructions from your rebuild kit, this is the write-up for you.  There is not likely any new information here; however, I have tried to compile a short list of tried and true techniques that I have personally had success with.  Let’s start with the Anti-stick Spring.

700R4 Anti Stick Spring

 

Anti-stick Spring – This is the small (.015” diameter) tapered spring which goes between the Throttle Valve and the Valve Body casting (or TV Bushing if equipped).  This spring is used to keep the Throttle Valve from sticking, which helps to maintain control of throttle pressure.  This spring works well to upgrade an OEM or a smooth tailed Throttle Valve; however, it tends to actually get hung on replacement valves with grooves on the tail (pictured above).  If the spring hangs on the grooved valve, it causes throttle pressure to remain high.  I suggest avoid using the Anti-stick Spring with the grooved Throttle Valve.

Steel Plate in servo modification – Cutting grooves in the Steel Plate in the Servo is a common modification.  This is done to allow for a less restrictive flow of oil from the second and fourth pistons.  In the photo below, you will see the four grooves tucked behind the snap ring.  A bench grinder was used on this particular plate.

700R4 Servo

Separator Plate Slugs – Used in two locations given the Valve Body does not have a roll pin and/or transmission has an Auxiliary Valve Body.  Check the existing Separator Plate for holes in the following locations.

700R4 Separator Plate Gasket

If the existing plate looks like the one pictured above, slugs are needed in both locations on your new plate (assuming the new plate has holes).  Insert slugs with a hammer (lightly), with the round side of the plug facing up, from the Valve Body side of the plate.  Slugs will not install flush with the plate, there will be a small margin of the slug visible as shown below.

700R4 Separator Plate Slug

Lining up Valve Body Gaskets and Separator Plate – If the dowel pins are not present or have receded into case, use a hand full of the Valve Body bolts to line up the gaskets and plate.  Thread a few bolts into the case starting near the Shifter Detent and working diagonally towards the 1-2 Accumulator.  Then go ahead and mount the Accumulator and Auxiliary Valve Body, remove the bolts and install the Valve Body.  This is one of those techniques that may take a little time but seems to always work.

700R4 Valve Body Gasket

Oil Pump Pressure Regulator Valve Modification – By grinding a single machined ring off of the Pressure Regulator Valve, more consistent line pressure is presented to the converter feed.  This modification is said to extend the life of the converter, and is a common upgrade with some shift kits.

700R4 pressure regulator valve body modification

Say goodbye to the Load Release Spring Assemblies – These assemblies are used to assist with the release of the 3-4 Clutches however, they are known to restrict the clamping force necessary to hold the clutches.  This restriction results in premature wear of the 3-4 Clutches.

700R4 load release spring

There are many other tips that usually come with the instructions in your rebuild and shift kits.  These may include drilling a .093” hole into the Valve Body Separator Plate, some kits come with a drill bit to accomplish this.  Also, ensuring the 4th Accumulator Piston is oriented a specific way is another common suggestion.

What I have found is that when working on these transmissions, the technical handbooks and various instructions that come with the rebuild and shift kits may seem to conflict on certain points, leaving you uncertain about which route you should take.  Understand that aftermarket kits use a combination of alterations to improve various operations of the transmission.  Once you begin altering the stock combination, the transmission will definitely perform differently…the science comes into play when getting it to perform the way you want it to.

Another thing I can tell you for certain is, if you have an Auxiliary Valve Body, and you put a checkball here….

700R4 check ball 5 removal

You will definitely experience 1-2 tie-up, burned Lo and Reverse Clutches as well as a burned Band.  Don’t ask me how I know!  All I can say is thank goodness for Transmission Dynos.  Ouch!!!  Apparently when the Auxiliary Valve Body was added (1987-1993), checkball #5 (pictured above) was removed, and checkball #12 (Forward Clutch checkball) was added to the Auxiliary Valve Body.  This was done to force Forward Clutch feed oil through an orifice.

It doesn’t take much to get the flow of fluid out of whack in these transmissions.  As you could probably tell, in this write-up, I tried to explain the “why” as much as possible.  When in doubt, take time to figure out how the transmission works, because you can’t fix burned clutches with new clutches.


Atlas Concepts LLC_Jordache Williams_Shop TalkJordache Williams, of Rock Hill, South Carolina, is the Program Manager for Atlas Concepts, LLC.  He understands that sometimes a small piece of information is the difference between success and failure. His contributions to the Shop Talk blog are purposed with sharing relevant information based on his own experiences.

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