The same Valve-Bore in the THM700-R4 also offers a Cross-Leak via a different Circuit...
That is a very Popular Modification for those Throttle-Cable TV Valve-Bodies.

 

last night i bought a used 4L60E and 4L60 GM powertrain manuals. i am going to attempt to figure out the way to do this on the 700R4 next as these are mostly the units I have built.

 

Didn't catch the separator plate only part! LOL

 

2 thank you's are in order
1st) the challenge to dig deeper causes learning... So thank you!!
2nd) Thanks for the vote of confidence, the hints and that there is more than 1 way to do it.
But a confirmation that something would work, is great! from a GM Hydramatic engineer...Priceless

 

Someone has been in my PM's and if they decide to try it their way...they could very well be the first mouse to this cheese on the post
Not naming names...but if yall are racing to results, you better get to testing before someone claims 4th place

(me/vortec/sonnax 1-2-3 in no particular order....and I'm sure there are some others out there that could have done the same and never said a word)

 

I've been learning via this thread and the PDF with the hydraulic circuits to do the OD range 3,2,1 overrun clutch mod and my valve body has low vacuum in the 3-4 shift circuit (probably why no 4th but everything else works great after full build using the monster kit with all the options plus input sleeve support and matching piston, pinless accumulators etc)

so i got a GM054-HD from summit and took pictures plus compared it to my plate and marked differences (still have to drill the new plate for the SHIFT shift kit plate mods).

First observation NO Sonnax 3-2 HD Shift valve, there using oversized but stock valves in problem locations and stock on the rest.
I'll post pics

 

GM054-HD 3-2 Shift valve

GM054-HD plate

4l65e stock 2003? Plate differences, 3 blocked passages (weld washers of same thickness in , smooth to perfection), 2 drill holes 6mm

 

This is how I do it. No sonnax valve, Two holes to block with simple aluminum pegs i make and cut slot in gasket all done. Been doing this way many years .

 

I found 1 last difference while going over the plates between stock and the GM054-HD and its three circuit 26b is not drilled in the plate, as far as I can figure out 26a goes to 26b which activates the "Regulated Apply valve" ? Am I wrong or is this valve not needed to be activated for lockup in 4th?

I only see this circuit being used (when in OD range) in 4th

Any help is appreciated i don't wanna screw this up.


Stock 2003 plate on top of sonnax GM054-HD plate. Circuit 26 in question


Isolator valve (model dependent) the upgraded T.C.C. valves over years eliminate this i believe?

Please let me know if I'm incorrect and I'll fix the information, but it looks to me like the newer/aftermarket valve designs eliminate the Isolator? If so the hole would just be wasting a little line pressure?

 

I have been studying this transmission for a few months now, because I need to rebuild one. And this is a mod I think would be good to do on mine.

The simplest way I could think of:

Drill a hole between the 35c/39 and the bolt hole so that the (valve body) 17 chamber feeds D4 fluid to (case) 39 chamber
Block 38e/39 hole so we now don't backfeed D4 into the D2 circuit

The #5 checkball should prevent backfeed to D3 but you could leave it out if you use the Sonnax 2-3 HD shift valve

Am I missing something?

 

Actually Franks way requires blocking 2 holes and no drilling. Fully reverse able with a new gasket.

 

This one would be block 1 and drill 1 on the plate, also fully reversible with the same gasket. And you can decide the feed orifice size yourself.