700R4 build thread.

[clinebarger]

If using a TransGo SK-700 or SK-700 jr, A Band shim is included. Install Servo & Shim without the Blue Cover O-ring.
If the Output turns both directions, Leave the Shim in. If the Output is locked, Take the Shim out.

The factory procedure is to use a Servo Pin Depth Gauge Tool, I don't use the tool, It's a PITA to set-up & I really do not trust it.

I do a Wiggle Test with a 90 degree Awl, I like around 1/8" total up & down movement. Install Servo & check before final assembly!! Use Apply Pin Length chart below for selection for a loose or Tight Band.

Sonnax has a extra long Apply Pin that be ground to a Custom length http://www.sonnax.com/parts/2477

[clinebarger]

Now that the band clearance is set, Remove Servo & replace all seals.
2 Scarf cut seals on the 2nd piston, Then the Red O-ring.
1 Scarf cut seal on the 4th piston. (The tall knob on the 4th piston faces OUT toward the Servo cover!!)
Install Blue O-ring on Servo cover
Install 2/4 Servo assembly in the trans.

[clinebarger]

Time to install the Front pump.

Place the Pump to Case Paper Gasket in the Case, Orient it correctly with holes in the case. 87 & up use the gasket with Reliefs cut on the Pump Bolts holes, The Early ones do not (A lot of seal kits come with both)

Stick the Plastic Thrust washer to the Back of the Pump/Stator shaft with TransJel, Make sure the locating tabs go in the machined holes.

Make sure the Pump O-ring is installed, Lube with TransJel.

Lube the Stator Shaft Sealing rings, Center them by hand afterward.

Lube Stator Shaft Bushings.

Locating Dowels are handy, Cut the heads of 2 long 8x1.25mm bolts, Thread them in the Case 180 degrees apart.

Orient the pump over the Case/Locating Dowels, Lower Pump until it stops.
Work the pump down with hand pressure, The 1 piece Stator Rings like to fight you, The have to shrink pretty good to get past the Reverse Input Bushing, You can Work the Pump down with a Dead blow hammer....LIGHTLY & alternate where you hit.

Do Not force the pump down with bolts, You will most likely roll one of the sealing rings, Then you will not have Reverse.

Once the Pump is bottomed, Remove the Dowels.

Put new O-rings seals on the Pump Bolts (Early model bolts take sealing washers)
Install bolts & Torque to 18 ft.lbs in a star pattern.....Yes you NEED to torque them!!

[clinebarger]

Check Endplay again, Spec is .015" to .036", Use Chart below if out of spec.
The Selective is under the Input Drum Torrington bearing.

[clinebarger]

Turn Trans so the Pan rail is facing Up.

Install the TCC Solenoid & Governor Thimble Filters, Push them in with a pocket screwdriver.

Install the Case Checkballs as shown below, If using a Shift Kit...Follow those directions!

The Green Arrows....These are "Z" holes/Alignment holes.
Cut the heads off 2 6x1.00mm bolts, Thread them in the Z holes, They act as dowels, This will align the gaskets, Plate & Valve body.

First pic, '82-Early '87, Install #9 Checkball.
Second Pic, '88-'93, Omit #9 Checkball.

[clinebarger]

Z holes, Green arrows.

[clinebarger]

4th Accumulator, AKA 3-4 Accumulator.

Check for wear at the Pin hole in the Piston, Insert the Pin in the Piston, Should be very little side to side movement...I see Very few 700's that have good Accumulator Pistons.
Check Pin for wear as well, Visually & with a Micrometer.

Install new Seal on Accumulator Piston.

Most '93 B-Body 4th Accumulators have no Spring, Install piston with "legs" Up...Toward the separator plate. (For the OP's Trans)

All other stock 700's, Install Piston "Legs" up in the Case, Then the Spring.

You can put the Spring in the Case, Then the Piston "Legs" Down. (Keeps the spring off the Separator Plate).

You can also Block the Accumulator with a Cup Plug or Checkball, I use Cup Plugs.

Whatever you do with the 4th Accumulator, It doesn't make much difference, As in, Firm to Hard 3-4 shifts are not possible with Accumulator manipulation or Blocking it all together.

[clinebarger]

Separator Plate.

Use a TransGo 700-P separator plate, At less than $20....Using the old plate is pointless. The holes are optimized for stock-mild builds, If using a Shift kit....Follow the directions for hole sizes.

This Plate Fits ALL 700R4's, Depending on what year/model you have, A couple holes may need to be plugged. The Plate comes with 2 Aluminum Plugs. This is EASY to do, Place the plate on a smooth concrete floor, place the plug in the desired hole, With a Ball-Pein hammer whack the plug a few times (Do Not strike the Plate!!), This will expand the plug & seal the hole.

First, Identify what Valve Body you have,
1st design VB's have separate 1-2 TV & Low bushings (Has a Roll-Pin for the Low Range Bushing).
2nd design has a Combined 1-2 TV & Low bushing (No roll pin), If you have the 2nd design VB, Plug the Hole in the Pic.

If Trans has a Auxiliary Valve Body, Plug the other hole in the Pic.

[clinebarger]

The above Pic is a Non-Auxiliary, 1st Design Valve Body Separator Plate.

This is a Auxiliary, 2nd Design Valve Body Separator plate, The Circle's are where the holes in the TransGo plate that needed plugging....If needed.

Just Info, It's easy to just tell someone to do something, I want to show Why you need to do it.

[clinebarger]

1-2 Accumulator

Inspect Accm. Piston for Pin wear.
Inspect Pin for wear.
Inspect Accumulator Housing for wear.

Install new seal on Accm. Piston.

'82-'92, Install Piston in bore with "legs" up, Then Spring.

'93, Install Spring in Bore, Then Piston with "Legs" Down.

The '82-'92 Stack-up produces a later...Firmer 1-2 shift.
The '93 Stack-up produces a earlier...Softer 1-2 shift.

[clinebarger]

Auxiliary Valve Body/Forward Accumulator.

Remove the 3 8mm headed bolts over the Forward Accumulator assembly.
Remove Spring & Piston.
Check Piston Pin Bore for wear.
Install new seal on Fwd. Accm. Piston.
Clean Bore of all clutch material.

Check Cover and see if the Pin can pass though the hole in the center of the Cover, If it can pass through....Obtain a later style Cover OR Braze/Weld the hole shut & drill a oil relief hole elsewhere in the Cover. If the Pin was to work out, You would loose Forward & Burn the Forward Clutches.

All Aluminum Covers have a narrowed-Oval hole.
If you have a Iron Cover, Check it!!!

[BADAZ chevy guy]

Originally Posted by clinebarger

1-2 Accumulator
Install new seal on Accm. Piston.

'82-'92, Install Piston in bore with "legs" up, Then Spring.

'93, Install Spring in Bore, Then Piston with "Legs" Down.

The '82-'92 Stack-up produces a later...Firmer 1-2 shift.
The '93 Stack-up produces a earlier...Softer 1-2 shift.

In my 93 I still want the firm shift. Is it okay to install the accumulator 82-92 fashion, or is that not possible in the 93 models?

[clinebarger]

Originally Posted by BADAZ chevy guy

In my 93 I still want the firm shift. Is it okay to install the accumulator 82-92 fashion, or is that not possible in the 93 models?

You can install it either way. If you find the 1-2 shift to firm after the Band Seats, You can always put it back the factory way.

Here's some info to make this easier to understand.

[clinebarger]

Valve Body Gaskets, Separator plate, 2nd Accumulator, Aux Valve Body.

Use '88 & up Auxiliary VB gaskets with TransGo 700-P Plate ONLY, Even if your running a early Non-Aux trans, The Late gaskets fit the Plate better.

The Aux. Gaskets are identified by painted stripes in the Gaskets. And the Aux. VB holes

Recheck that the Case Checkballs are in place & correct.

With the 2 home made alignment dowels threaded in the "Z" holes.

Place The CASE gasket on the Case, The Gasket is identified by the letter C cut into the gasket.

Place the Separator Plate on the Case Gasket.

Place the Valve Body Gasket on the Separator Plate, Identified by the letter V cut into the Gasket.

Place the 2nd Accumulator Assembly on top & Start the bolts.

Place the Auxiliary Valve Body on top as well (Install #12 CheckBall on the plate or TransJel it to the Aux. VB), See post above for Checkball location.
Start the Aux. VB to Case bolts.

[clinebarger]

Valve Body...

It is very important your work area is clean, Any Valve or Valve Bushing needs to be cleaned as well as the Bore it is removed from. I use a Solvent Blow Gun & New Clean Solvent, Blowing Solvent is hazardous to your Lungs.

Always place your finger over the hole a Bushing/Valve is in when removing a Roll Pin, The 700 isn't to bad about this (The 3-2 Spring IS), Just a good habit.

Let's start with the MOST important part (And gives the most issues) The TV Valvetrain.

Remove the TV Plunger Bushing Roll Pin.

Remove Plunger & Bushing, Use the Plunger Valve as a slide hammer to remove the Bushing, Use fingers, Not Pliers, Dykes or any other tool if you plan on reusing the Plunger or Bushing. New "94 Code" Plunger assembly is a recommendation.

Remove TV Spring.

Remove TV Valve Roll Pin. See Pic.

Remove TV Valve.

[supercheyenne]

Great thread clinebarger!

I gotta admit it's a bit overwhelming though. I do want to rebuild a transmission someday.

[clinebarger]

I highly recommend using a TransGo TV correction kit (Included in their Shift Kits SK 700-JR & SK-700) It will eliminate TV valve sticking problems that plague 700R4's.

[clinebarger]

Install the New TV Valve in the Valve Body Bore with BOTH return Springs.

Push the Valve down a little & Install the Roll Pin.

Check TV Plunger Bushing for wear, Move the Plunger Valve through the Bushing & Check for wear buy rocking the Valve in several locations. Keep in mind this is a High Wear item, If worn use this http://www.sonnax.com/parts/2512.

Install Red TransGo TV Spring into Plunger Bushing.

Insert TransGo Spacer into Spring.

Install Plunger Assembly & TV Spring into Valve Body Bore.

Install Roll Pin.

[clinebarger]

Accumulator Bushing & Accumulator Valve.

The Accumulator Valve controls the pressure in the Accumulator Oil Circuit, The higher the Accumulator pressure, The Firmer the shift.

The Pressure is manipulated buy using different spring weights, The heavier the spring, The higher the pressure. This affects the 1-2 Shift feel.

The TransGo 700-jr has 3 different Accumulator springs, Orange being the Firmest, Brown being a Medium weight, & Black being the Lightest.

Remove Accm. Bushing & Valve from the Valve Body, Check for Bushing wear, & the aluminum end cap fits snugly.

Check the LETTER code on the Accumulator Bushing BEFORE selecting a Spring weight!!

This valve train has 7 different OEM size variations: B, A, N, M, L, K, and F. They range from the largest valve diameter giving the firmest shift (B) to the smallest valve diameter giving the softest shift (F), respectively.

[clinebarger]

Accumulator Valve continued.

Assemble Valvetrain as shown below, The spring likes to hang-up in the bore, Turn the Valve Body with the Bore facing down during install.

The TransGo SK 700 (Senior) comes with a wire retainer that goes behind the 1/8" plug/4-3 pressure switch directly above the Accm. bushing, This allows Spring/Valve/Bushing changes without dropping the Valve Body.

The SK 700-JR doesn't always come with the retainer, Make your own if needed.

Not All Valve Bodies are tapped for the 3-4 Pressure Switch. If so Install original Roll Pin.

[clinebarger]

An overview of what we are working on.

[clinebarger]

Line Bias Valve.

The Line Bias Valve matches Line Pressure to Torque Rise. After about 60% throttle the Line Bias Valve starts to open & bleeds off Line Pressure.

The rate it opens varies on what Weight Spring is installed.

This is a BIG concern when installing a random 700R4 behind modified/Torquey engines because GM matches the Line Bias Valve Spring to each application.
A TPI Vette has a stiffer spring than a 4 cyl. S-10 for example.

The TransGo 700-jr has a Line Bias spring that works very well even with small Boost Valves & Even Better with Larger Boost Valves.

**NOTE, DO NOT block the Line Bias Valve, There are applications that would call for this, Like a Big Block that gets full throttle all the time, But then again....Why use a 700 in this circumstance??**

[clinebarger]

3-2 Downshift Control Valve

Remove the Roll Pin, (Place finger over the hole, This spring will launch into orbit).

If you want a easier 3-2 Downshift, Omit the Spring, (I would leave the spring out, & see how you like it) If the 3-2 downshift is to active for your liking you can reinstall the stock spring.

If your shift kit comes with a 3-2 valve spring, DO NOT use it! It is generally stiffer than the OEM spring making 3-2 downshifts hard to obtain.

Install the Valve as shown below.

Followed by the spring if you want it.

Install the Roll Pin through the top of the Valve Body, So you can remove the roll pin without dropping the Valve Body.

[clinebarger]

OK, Time for the other side of the Valve Body.

Lets start with the M.T.V. Up & Down Valves. M.T.V. stands for Modulated Throttle Valve.

Modulated T.V. Up-Shift Valve Info.

TV oil (From the TV Valve) increases with throttle opening & delays Upshifts under heavy acceleration.

At light throttle/Part throttle (PT) line pressure ramps-up quickly, If TV pressure was sent directly to the TV Shift Valves....PT Upshifts would not take place until a pretty good speed was reached (For Governor Pressure to overcome TV pressure)

The MTV Up valves job is to Modulate TV pressure sent to the 1-2, 2-3, 3-4 & Converter Shift Throttle Valves under 50% throttle.

The MTV Up valve starts to open around 10% throttle & is fully open around 50% throttle (Depending on Spring weight)

Under 10% throttle, TV pressure takes No Part in Upshifts, It is handled 100% by Governor pressure.

Over 50% throttle, All TV pressure is sent to the TV Shift Valves, Now the upshifts can be delayed by full TV pressure under hard Throttle.

This chart may help.

[clinebarger]

M.T.V. Down-Shift Valve

Starts to open around 40%, fully open at around 65% throttle.

This valve acts as "Detent". Similar to a TH350 Detent cable or the TH400 Detent Solenoid....Except completely hydraulic.