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Hi all, amazing info here. My question refers to something I read from Dana at PBA, concerning removal of the checkball near the band release hole. This assists in the 3-4 apply oil circuit. I attached pics, is this the checkball where my pen is pointing?
If you remove that check ball and plug the hole you can (should) also increase the band release hole to .106 and the third apply to .140. Then remove the spring from the 3-2 valve and block it inboard.
To give a little background on how/why you do this...the checkball (#2) is "unseated" during a 2-3 shift and allows full flow of 3rd accum oil. 3rd accum oil is oil that goes to both the 3-2 control valve and the backside of the 2nd gear servo (to push the band off)
If there is a leak at either the checkball in the case for the 3rd accum (typical) leakage around the band pin (VERY typical) or at the 3-2 control valve (typical) then you're wasting a bunch of oil and pump volume that should be going to the 3-4 apply piston. So...you block the 3-2 control valve inboard to fix a bunch of the leak there, and you block the checkball to reduce flow to the other 2 leakers that aren't as easy to fix. You have to open up the orifice hole (called the band release hole because it is what pushes-off the band aka releasing it) so that the 2-3 shift timing is correct. If you don't open it up, then the 3-4 will apply before the band releases and you'll actually shift from 2nd to 4th (for a split second...because 3/4 clutches are on and the band hasn't yet released) then into 3rd
One thing to keep in mind is, now with the 3-2 blocked, you don't have that quick exhaust path for 3rd accum oil on a 3-2 downshift...but now that you've open'd up the orificed hole, you still get a good exhaust path. So it works out fine.
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Like Jays says...open 3rd feed to .140 and open band release to .082 if you block the check ball and the 3-2 control
Thanks for the response Maroon. Why I ask this is I am getting ready to rebuild my Silverado, and have been looking around for mods to do at that time. I rebuilt my yukon about 6 years ago, and is still going strong, but since then have been looking for tips and tricks, knowing my truck would need a rebuild one day. So no, not really trying to fix a problem, just pretty curious about the hydraulic circuitry of the 4L60E.
That's a mod we saw from units brought in with the old B&M 4L60E shift kits. It's also used in Transgo 700r4 and 200r4 kits, some old tech still survives today.
TG instructions for hole sizing is trash in my personal opinion.
A. if NOT blocking the 3-2 valve, and you want slightly better than stock shifts, drill .100(3rd feed) and .082 (band release) (dont block the checkball)
B. if NOT blocking and you have a camaro or gto or a truck that you have increased power on, etc..drill .125/.093 (don't block the checkball)
C. If blocking the 3-2 valve and using "corvette" servo...drill .135/.100 (block the checkball)
D. If blocking the 3-2 and using a billet servo...droll .145 or .150 and .110 (block the checkball)
The band release hole really only matters for downshifts UNLESS you're blocking that check ball hole closed...then it can affect the 2-3 upshift timing.
Scenarios A and B drilling the band release hole only changes downshift exhaust speed for the band
Scenarios C and D drilling the band release affects the 2-3 upshift and the 3-2 downshift timing
@PBA please step in and correct me here if I'm speaking out of turn or sharing something that you see needing correction.
Also, I've personally drilled the 3rd feed hole .140, blocked the 3-2 downshift control, drilled band release to .100, and left the checkball alone. Worked fine.
You do not have to block the checkball hole for band release when you are making sure that the checkball sealing the plate is actually sealing against the plate. When talking to TransGo about this years ago, (1) they block this hole because of the "average" builder is not going to check this closely, and (2) it is more precise. I agree. I have done it both ways over the years. If I am building a 675+HP horsepower unit using a 9 clutch (someitmes10 clutch) using BW-Hi E's (set at .030" - .040" clutch clearance) and the Sonnax 2nd apply servo and blocking the 3-2 inboard, I'll use a 2-3 shift feed hole at .155" - .174" and a BR hole at .104". With the Corvette servo (up to 675HP), and everything else as stated above the 2-3 shift .135" - .140" and BR at .101".
You do not have to block the checkball hole for band release when you are making sure that the checkball sealing the plate is actually sealing against the plate. When talking to TransGo about this years ago, (1) they block this hole because of the "average" builder is not going to check this closely, and (2) it is more precise. I agree. I have done it both ways over the years. If I am building a 675+HP horsepower unit using a 9 clutch (someitmes10 clutch) using BW-Hi E's (set at .030" - .040" clutch clearance) and the Sonnax 2nd apply servo and blocking the 3-2 inboard, I'll use a 2-3 shift feed hole at .155" - .174" and a BR hole at .104". With the Corvette servo (up to 675HP), and everything else as stated above the 2-3 shift .135" - .140" and BR at .101".
Good to know I haven't been doing it wrong all these years haha. Thanks as always for popping in and sharing info
Originally Posted by sjsingle1
maroon......what 2nd servo ya running....vette or sonnax....i would say fairbanks but does anyone use that ?
have you blocked the checkb all in any of your trannys ??
jay....my TG instruction is from the sk jr kit ....wonder why diff
calling PBA.....WHERE ARE YA
Yes I have blocked the CB and not blocked. Didn't notice any significant difference because I always make sure check ***** aren't leaky.
My preference for most any 450 ish hp car is .125 3rd and .093 br...leaving the checkball alone. 7 or 8 clutches...clearance at .0025-.0035 per clutch. Works awesome. (with vette servo, wide band, and a new rev input drum)
Since checkballs are being discussed here, can I ask a question on the differences in the Jakes kit, and the CK Performance kit? They are almost identical, however when it comes to check *****, the CK kit uses several more chackballs than the Jakes. I know 1 checkball is for the reverse, and it has been mentioned that without it, reverse applies a little harsh, but as far as the others, I have not dug through them yet to see what they control or how removing them would change things.
A. I'm assuming you're referring to the 80e kits...this thread is discussing 60e stuff
B. it depends what kit you're using. The jakes kit blocks the accumulator feed holes with the separator plate, so there is no need for the 2 check ***** in that area. Leaving the reverse checkball out is usually fine by my standards for perforance stuff with higher stall converters.
That's a mod we saw from units brought in with the old B&M 4L60E shift kits. It's also used in Transgo 700r4 and 200r4 kits, some old tech still survives today.
True.
I personally have never been happy with any of the B&M shift kits... I do not use them...
As far as the THM200-4R and THM700-R4 units; I do not use the TransGo supplied 3-2 control valve and spring.
I prefer to use the OEM 3-2 control valve found in the THM200-4R and THM700-R4 units, but discard the OEM spring.
I block the valve inboard using the small spring from under the pump pivot pin found stock in both units.
Some builders use a 0.2500" cup plug on the valve instead of using the pump pivot pin spring.
Instead of OEM valve, OEM spring, then roll-pin... the order will be pump pivot pin spring, OEM valve, then roll-pin.
I usually install a new pump pivot pin and spring with the other pump parts during overhaul.
The original reason for this 3-2 control valve modification for high performance use; is because the 3-2 control valve acts as a big variable orifice for the 2-4 band release circuit in the THM700-R4 and the Intermediate band release circuit in the THM200-4R.
So, we block the valve in a static position; there by eliminating that "orifice". Then plug the check-ball hole and delete the check-ball; there by eliminating that "orifice"
Now there is one orifice in the separator plate left that the size is tuned for proper 2-3 shift timing along with the third feed circuit orifice size tuning.
Yes, I know that mod well vorteciroc. Chris from CK performance use to preach that mod way back in the turbobuick forum. He also wrote a piece about it in Gears magazine for his 2004R mods. Works great, I'm just pointing out how some old tech is still used and how it has evolved for the better.
03-18-2019, 08:02 PM
Checkball removal 
