Most of the builders Here are familiar with the sonnax HD 2-3 valve which keep the overrun clutch on in D3 2 and 1 positions to help protect sprag. The problem with this is How many actually drive around in D3 or remember to pull down when hitting it for a quick zip on the street roll or (street run) - nopt suggesting you should do this on the street . Or even towing.
A few years ago as we built the 4l60e as we approached the 1000 rwhp level while the 3-4 clutch set up used was holding well as were most hard parts, But we ran into the issue of sprag roll and sometime shatter with launches and sudden kickdowns. While I realized the Sonnax HD valve worked great to eliminate this in D3 the reality is no one really drives around in D3.
So out with the Hydraulics diagrams and boom I came up with this shown in the attached photo, it is a simple modification, it changes the feed for the overrun to the forward clutch instead of D3 oil.
You block the Two feeds in the bathtub and eliminate the check ball, then simply cut the valvebody side gasket as shown in the photo. connecting the two channels.
This results in Overun clutch being on in gears 1-2 and 3 even when in the OD position instead of just D3 protecting the sprag with the extra support and shock resistance using the overrun clutch.
The overrun clutch is then exhausted when the trans shift to 4th via the 3-4 valve.
Some might ask does this not also exhaust the forward clutch and yes to some extent however since it is doing nothing in 4th gear and the sprag is freewheeling this causes no issues.
This mod will eliminate input sprag roll over and shatter and is proven after years of use in very high power applications.

CONS for some , You will feel the downshift from 4-3 and 3-2 coming to a stop. (You won't feel the 2-1 as the low/rev clutch has to come on for that. (though I do have a mod for that too in super extreme launch applications) this is noticeable but how noticeable varies per tune and idle speeds can be a light bump as it is in my own car to a somewhat harsh feeling bump on the coast 3-2 but again its very dependent on the tune how it feels but this is harmless.
Excuse the cut being a little dirty like. It's harder to do with the bonded new plates I prefer to use. and yes you do leave the ball in the overun spot. This also negates the need for the HD valve , You can still use one if you like but it will serve no purpose.

 

I shared this mod a couple years ago I believe in a corvette discussion
I make separator plates that do this among other things. Makes it a simple bolt on deal

Cutting the gasket works as well, but the feed is limited, and plugging the plate can be a pain.

Orifice sizing can be revised to help with shift feel on a 3-4 up or a 4-3 down.

Frank if you'd like some separator plates I'd be happy to get you some of the ones I cut, really makes these easy!

 

Sure I would like to see what you do. I first did this in 2015 with the first black editions. I have slotted the valve body and or plate in various setups but chose the gasket cut to limit the feed as I was concerned about dumping the forward clutch oil which has pretty large feed and dropping overall line pressure. I had noted with larger slots or feeds I would see a couple pound drop in overall line presure on the dyno on the 3-4 shift that did not recover and none with the gasket cut method .However I doubt the couple lbs drop in overall line would matter much .
And yes blocking the holes can be a pain in the bonded plates . This photo is not an example but I have been using lathe to make little brass slugs to do it.

 

The way you have it will work just fine, But I prefer to do it a bit differently.
Neither of us are really re-inventing the wheel.
I've had plates made for quite some time now (2018 maybe?) that do this but GM did it first back in the early 2000's

The corvette did the overrun feed in D3 without the need for a special valve by blocking the bathtub holes and feeding the overrun by moving a hole over in the plate.
This would feed the overruns in D3 without the need for a special sonnax valve.

For anyone reading...you can do the exact same thing with a couple plugs and a drill bit if you'd prefer just a D3 feed of the overruns with no need for the sonnax valve.



I feed the overruns with D4 oil but differently. I like to use a custom plate I have laser cut, and I block all these holes in that plate for a cleaner install, but also so that I have precise control over my orifice size.
With a slot in the plate, or a slot in the gasket, your orifice hole no longer really counts. It relies on the size of the slot or gasket cut.
Custom plate also moves/changes other things like orifice sizing, accumulator oil, tcc and afl feedback oil, etc.
All things to help optimize the 60e circuits.

Now, regarding your drop in psi on a 3-4 shift.
I think we should re-visit this.
D4 oil feeds a tremendous number of things as I'm sure you know.
D4 oil is the basis for all clutches.
D4 oil is what (after all the valves and passages) feeds 2nd, 3rd, and 4th gear friction apply elements. It feeds real lube orifice (aka a constant leak), it feeds the accumulator valve and subsequently the accumulator oil circuit, it's used as 3-4 and 4th signal oil, etc
So the overruns being on via a slot in the plate or gasket should not have resulted in a hydraulic loss when shifted to 3rd.

I've not noticed the same psi drop when using my plates or doing this via slots in the past.

 

It was on 4th shift and was just tiny on gauge so nothing of concern I just decided this was an easy simple way so I thought I would share. Not saying my way is better just simple for anyone to do. I am sure your plates are great would love to see some and yes GM did the d3 thing in 2005 on the corvette.
But again the idea was to share a simple mod to save and pretty much make the sprag indestructible from my observations over the year that anyone can do in minutes during a build or shift kit.

 

You also made it a challenge to figure out on our own. Franks way is an interesting way to feed the overruns in D.
I am curious if your separator plate is for sale?

 

yes maroon and vorteciroc left us some bread crumbs to figure it out. I think I figured it out but haven't had time to get my Caprice running over the last year.

 

Yes it was in
https://ls1tech.com/forums/automatic...d-3-2-1-a.html
My idea was posted in #38 and I think that's where you reminded me of "separator plate only"
So share your Idea!!!
Frank Shared his and you can look at mine...
So share your idea!

 

Here was my PM to maroon last august:

​​​​​​
​​​​i can't take any credit here, like I said maroon and vortec left enough hints to figure it out. it probably would have been faster to figure this out had I had a 4l60e apart but I was in the middle of fixing my squarebody and had no free bench space. but i was able to figure it out by looking at the 4L60E technicians guide and studying the hydraulics.

 

maroon & vortec left clues & stated there was multiple ways to get it done. The challenge was thrown out to figure it out for our-self. So credit is due to you for figuring out a way!

 

Hmm at least I did get people in here talking lol. Like I said the mod I posted works and is simple easy to do really fool proof as long as you make sure whatever you use to plug the two holes stays put. As I mentioned I generally make brass plugs on a lathe one end slightly larger than hole then place in hole and hit back side with a hammer it stays. Optionally with non bonded plates a ball of soldier works same just hit both sides.
I am very sure it can be done a number of ways as I said mine is basically just simple, easy and free.

 

For the DIY guy without a lathe, a ball of solder peened flat into the hole works well
You can also drill them out to 1/4" and cut a small disc of aluminum rod stock to about the thickness of the plate then hammer/peen it in place also


@Tranzman Sometimes it is better to leave crumbs then confirm when someone gets it right
rather than to just spoon feed with the easy answer

Generally people will retain that way better and also start getting creative and share ideas back
I try to be helpful and freely share plenty of things I've learned/developed over the years. But if I spoon fed and handed out every little bit...I may as well just write a book and publish it.
After all...there are plenty of mediocre or flat out crappy 4l60e books out there and they sell!

 

Yes, these are the proven teaching methods.
Shall we refer to you as Professor in the future? Your knowledge certainly makes you worthy of the title.

 

publish that book....I will buy it !

trial and error is a good teacher....but sometimes it takes too long and can get $$$$$

 

I think the Professor meant that all the info is available in other threads here, and you will understand it better if you read the entire thread and not just his posts.

 

Lots of info in the threads for sure....sometimes it is a pain to find it tho....a rabbit hole on the level of alice in wonderland....and heaven forbid you find conflicting info ....more research !
thats why I always ask ...WHY ...I like a deeper understanding of why a mod is done and what it effects....good and or bad....like when the ATSG book told us to chunk the 3/4 load springs....now we know better
I was motivated long ago from a how to magazine article to rebuild my 700R from my IROC Z...it takes curiosity and perseverance to attempt such a thing as soooo many things can go wrong when you are a novice in the game.....so many ways to skin a cat...I just want to find out the best way to do it

 

I am Late to the Party (and seriously after a few Brain injuries, my memory is very poor)...

But Didn't I Give you guys like 90% or 95% of the Information on how to go about doing this???

Maybe sometime in the last 6 months to a year ago.
No Joking... I Can't remember.

Please someone confirm this for me, or everyone confirm this for me...
Try and cheer up a young guy that is literally loosing his mind well before hitting 50.

Please!

 

Yes you did!!! I posted my thoughts and maroonmonsterls1 stated that it looked like someone had read his personal notes or something like that.
Frank shared his way of doing it. So that opened a whole new thread. We got Tayto to share his idea.
So it seems you are correct there were 3 ways shared so far.
I'm glad you are still with us. We are trying the best we can while you recover.
I turned 66 in January and fully retired. They just keep calling and want to give me $$. I just limit what I do to 4-5 hours a day and 2-3 units a month. The extra *** time gives me more time to spend on the forums I belong to.

 

I am wondering about when you say to drill the hole to the nearest bolt hole what this means I have looked at the hydraulic manual and I think I understand how the rest of it works except for how drilling this hole provides d4 oil and is this hole in the separator plate and what size does it need to be I have yet to open up a transmission to do a rebuild but I hope to soon and I would like to try this on it and I don’t want to cause a problem so a little clarification would be great
thanks

 

Basically Franks way is simple, easily reversible & no holes to drill.
1st you block 2 holes. Maroonmonsterls1 stated a drop of solder will work ( I would chamfer the 2 holes first).
2nd you cut the VB gasket.
This feeds the overruns clutch with D4 oil through the original overrun feed hole 35E/36 and when the transmission goes to 4th gear, the oil is exhausted by the 4-3 sequence valve.
I think what they were stating was that you would drill a (I would use a .110-.125) hole through the bathtub wall of the valve-body in the direction of the bolt.
Like vorteciroc said there are many ways to do this. In my opinion Franks way is the simplest.