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4R70W Rebuild Diary - PART 21 - VALVE BODY UPGRADES

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Glacier991

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[This thread is under construction, and is locked. Please be patient as I upload the pix and paste them and as I develop this thread. THANKS!]

The 4R70W Valve Body has undergone a slow evolution from the AOD up to the 4R75W current version. Breakpoint years have been 95, 98 and 2001.

As compared to say the 5R55E Valve body, the 4R70W valve body has been "relatively" trouble free a valve bodies go. The EPC is mounted in the case, NOT the VB, and that may have some bearing on it, IMHO.

Against that background, it should not come as a big surprise that there are not a lot of upgrades out there. As is always the case the separator plate and the hole sizes are a prominent "mod" to change response characteristics.

Sonnax, has a few changes available to this VB.... and Transgo makes a "shift kit" as well. Plus, of course, the inevitable separator plate modifications mentioned above.

This thread will explore the upgrades to the VB proper, and the next tread will explore the separator plate modifications.

We'll start with the Sonnax upgrades first off.

SONNAX's OFFERINGS FOR THE 4R70W

Sonnax has 3 main offerings for the 4R70W. (Not counting adding a spacer to increase spring pressure in one bore, which we'll cover.)

They offer an upgraded Pressure Regulator Valve (P/N 76948-01 for up to 95, and 76948-09 for 96 and up). To that they add a pressure regulator boost valve and sleeve (same for all years, P/N 76948-02K) These pics show the parts side by side and their installation. First off the parts. Stock on left, Sonnax on right:

Picture_0181.jpg


And here is the installation. First off this is the bore....
Picture_0151.jpg


Notice the manual valve in the picture.... that should give you a reference. To remove it you need to unload spring pressure on a sinple retaining clip. I used a butt end of a ball point pen to do this..

Picture_0161.jpg


Using something to grasp the retainer (I used miniature needle nose pliers) and pull it out...

Picture_0171.jpg


Use something to gentle urge the old spool out and then put the new assembly back in... I like to lube mine first with ATF... push is gently into place....

Picture_0191.jpg


Line up the end plug so the retainer can go back into it's slot.... and using your finger push it back into place....

Picture_0201.jpg



So now you have 50% of the Sonnax upgrades out of the way!

Next, we are going to turn our attention to the "Bypass clutch control valve".. this one will also have a separator plate drill-out associated with it.

It sits right next door to the pressure regulator we just replaced. It is held in place by a square retainer....

Picture_0261.jpg


Remove it and then remove the valve and spring...

Picture_0241.jpg


Here is the stock (left) and Sonnax (right). Remarkably similar....

Picture_0252.jpg


Replace in reverse sequence of removal.

The also offer a O-ringed bore end plug for the 2-3 shift valve bore. Here is that bore identified:

Picture_0211.jpg


Here is the old style end plug on the right and on the left the new version.

Picture_0221.jpg


This is how it goes into the VB... O-ringed end out...Pretty easy, compress it slightly and remove the clip (just like the previous one you saw).. take out the old end plug and insert he new and replace the clip, like so.. (push in the plug to align it and push down the clip)

Picture_0231.jpg


And finally they legitimize a practice I understand has long been used by custom rebuilders, adding a 2nd "retainer" to the solenoid regulator retainer to increase spring pressure. You could use most any end plug that will fit from other trannies.... but the Sonnax one is .092 thick and looks like this:

(pic coming)

Here is the regulator spool out.... with the stock retainer

Picture_052.jpg


And here is reinstalled with the added retainer doubling up with the stock one....

Picture_053.jpg


TRANSGO KIT

It should come as no surprise that the Sonnax offerings and the Transgo cross over - after all they are adressing known trouble spots. The Transgo kit is designed to cover the period of 91-2004. There's a lot of variations in that time frame, and a lot of the kit didn't apply to my year and VB type. I'd suggest the Transgo that they reduce the price and break the kit up into periods...

The Transgo kit, after installing the Sonnax mods really did not have a lot of new things to add to the spools/bores (but lots elsewhere and some new stuff here). They add a spring to the inner piston in the pressure regulator bore (which I added) (Pic coming)


And they add an entirely new spool in the solenoid regulator bore... along with a stronger spring. (Remember this was where we increased spring pressure by adding a "shim" as an endplug. I removed that Sonnax "shim" and went with the new Transgo setup.

(pic coming)

They also have some places where they have you drill thru the wormtracks.
I'm inclinded to do that but I want to call them and find out what we are accomplishing so I can share it with you - in the case of the EPC relief valve it is pretty obvious, there there is another spot where I am not so sure.

They also add (as mentioned) an EPC relief valve (Great idea) and quite a variety of springs etc for the accumulators (more on that in the accumulators section.)

Finally, they like everyone else have some sep plate drill outs...AND a place where they REDUCE a hole size - that will be a fun post all its own.

One of the things I find most interesting with the Transgo kit is their comment:

"A main goal of this kit is to reduce and cushion against sudden inertial and torque loads against driveline and internal parts during kickdowns and upshifts. Sudden loads distort internal parts causing them to come apart, break or wear quickly. Kickdowns will be different to reduce engine and convertor runup against sprags.

POLICE/TAXI: During jackrabbit stops and starts, start off will be 2nd, not 1st, for about 1 turn of the wheels. This takes the fast throttle "WHACK" off the driveline and reduces the 301 KD engine runup and whack against the low roller."

I salute Transgo. Clever guys. Good products. Their kit runs about $45.

At the end I will post my thoughts on where to go with Sonnax and where to go with Transgo - and where to mix their products.

(Stay tuned, more pictures, more talk, more info coming.)
 




Glacier991

EF Tranny Guru
Moderator Emeritus
Joined
February 8, 2003
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City, State
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Year, Model & Trim Level
1992 XLT
If you have questions, comments, ideas or just feel an overwhelming need to post about this thread, please go here ...

http://www.explorerforum.com/forums/...d.php?t=161450

I am trying to make it easy for folks just wanting basic information. The questions etc can have their own thread. Thanks for understanding.
 




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