4L60E TCC Valve - blocking the valve vs. sonnax kit

[cybercide]

I have a 2000 camaro with 85k and the 3800 V6 & 4L60E automatic with a very intermittant famous problem, the hard 1-2 shift. Only once once threw the P1870 code.

So I talked to a guy at the local trans shop (really local and really small, one guy fiddlin with his own jeep) about having a Sonnax TCC valve kit installed. The guy was familiar with the 4L60E and the Sonnax kit, and has the equipment to ream the valve body and install it.

He said he used to use the sonnax valves before - but now he just blocks the valve. With a piece of brake hose in there somehow, I am not that familiar with transmissions so he kinda lost me in the description. Basically, he said, it is then either on or off, no more PWM, and the problem solved because no more valve. He claims to have many 4L60E's on the road with this fix.

As far as price quotes, he wanted 450 to do the sonnax kit along with disassembling the trans pan replacing gasket and fuild, which seems high from what I've read in other peoples posts. To do the full job and just block the valve it was 300. I also mentioned that I was considering removing the valve body myself and taking it to a shop, and he said he'd block the valve for FREE if I went that route....

Obviously that "free" route is appealing. Not totally free, I'd still throw him some cash for helping, have to buy gasket/filter/fluid, and do the grunt work myself, but that is a nice low cost option. I googled a bit and found other reports of fixing it this way so I know the guy wasn't just smoking crack. AFAICT it can be undone in the future and a Sonnax valve installed if I so desired.

What do you all think about blocking the TCC Valve versus the Sonnax TCC Valve kit? What would be the negative aspects if any?

[CDNFB]

Re: 4L60E TCC Valve - blocking the valve vs. sonnax kit

Wow. I've never heard that one before!

Blocking TCC valve would work mechanically without damaging anything. I believe the operational consequence is that you will loose your torque converter lockup and without the lockup you will get worse gas milage, higher than normal transmission temperatures due torque converter internal losses (but not as hot as from the friction by the partially engaged lockup caused by the leaking TCC valve), and you could still probably throw a P1870 Component slippage code.

Here's my take on this. The hardest part of the whole Sonnax valve thing is lifting the car off the ground and dropping the tranny oil pan, and you have to do that regardless of what fix your going to do.

When you get the oil drained and the filter out of the way, it's really a piece of cake after that. And if your tranny guy says he'll ream the valve body for free!!! Well thats a great deal.

I've done this job myself, but I took the valve body in to get reamed and the TCC valve installed which cost me a little. I say give it a shot, you'll save a whack of dough.

[cybercide]

Re: 4L60E TCC Valve - blocking the valve vs. sonnax kit

Well I can't get it reamed for free. He said he'd help me block it for free. No reaming required for that, said its real easy. Since there is no real physical modification done to the trans or valve body, aside from removing a spring I think, it should be completely reversable or reamed to any size later if I choose.

The torque converter still locks up right? I think theres just no more PWM anymore. But I don't exactly understand where Pulse Width Modulation comes into play in the trans and torque converter? I think it makes it more like the older 700R4 but really I haven't quite grasped the whole concept...


Links

s-series.org: 4L60E tranny still shifts hard....what gives??
http://forums.s-series.org/viewtopic.php?t=44240

ImpalaSSforum: 1870 Fix - 4L60E "mod A method 2"
http://impalassforum.com/cgi-bin/ult...=4;t=006765;p=

Transbuilder.com forum snippet
http://www.transbuilder.com/tour_forum.html
(says Free, no copyright listed, so I'll do a big relevant quote)

More 4L60E...

QUESTION:

I am seeing a pattern of 1996-1997 4L60e's come in with a code P1870, which in common transmission English is RATIO ERROR. Now I realize that just about any component in the transmission slipping could trip the code, but it seems to be, the TCC not engaging that is usually the cause. I have one right now that I'm working on. It locks up fine when cold, but after it gets warm, the VCM commands Lockup, but the TCC slip is well over 150 rpms, and no lockup is felt. I've hooked up the TransX2000 and monitored the actual voltage to the transmission when the VCM is commanding lockup, and the voltage is being sent from the VCM. Next I override the VCM and apply the lockup with the lockup feel PWM duty cycle at 40%, no lockup, BUT if I raise the lockup apply feel PWM duty cycle to above 55% it works. Does his tells me the oil PSI in the TCC apply circuit is too low? Sure sounds good, especially being that it only does it when hot. I've been replacing the pumps and the converters to correct this condition, but I can't see a thing wrong with them, though it does solve the problem. I know that we put in a few AODE converters before we found an easier fix. SO, here I go into the "what if" field. What if we could somehow raise the TCC apply feel PSI that was being sent TOO the PWM TCC solenoid, would it help, or even correct the no lockup condition? I looked at increasing the TCC apply feel valve spring, but the spring the factory has in it, looks like it has been taking steroids already. I think I may shim the spring tomorrow and just see. I wonder what would happen if I just blocked the apply feel valve? Here is another thought, what if we unplugged the lockup apply feel solenoid, and just plugged up a dummy solenoid to the wiring harness to satisfy the VCM? Any body got any ideas? You know I am beginning to dislike the letters PWM!
Dan Tucker

RESPONSES;

* Fri, 07 Nov 1997 09:15:42 -0600
Gentleman; If you add a spring to the isolator(pushing isolator toward regulator valve), or increase PWM oil to the isolator,the regulator will stay in a max. flow position. But...the regulator bore is often so worn out that converter apply oil leaks too excessively to control/hold the TCC clutch when hot. Until this is addressed, numerous shops are bloking the regulator to max. on RWD units. This is too severe on the 4T60E. When the bore and valve are worn, your converter apply oil goes out the window to exhaust. Inspect and Wet/air test the regulator valve. (keep this in mind on all the PWM GM's.)The regulated PWM converter apply circuits are not routed oil from the pressure regulator valve as in "the good ole'days. The 4L60E pwm oil circuits are not correctly illustrated. If you work through signal and apply circuits you will see this. Good Luck...isn't this fun!
BWsonnax

* Fri, 7 Nov 1997 23:01:16 -0600
BW SONNAX
First thanks for spending your time on the net. Sonnax products and research are a asset to the rebuilding industry. How do you recommend that we set the PWM to maximum? I, like you, am uncertain about the literature on the 4L60E. I think until we get a fix for the 1996 and up 4L60E transmission we may need to consider 'bypassing' all PWM.
Dan Tucker

* To clarify what was meant by setting/getting full PWM oil is...opening the plate orifice between the plug and the solenoid. This is about all you can do to assist TCC/PWM boost. If you increase actuator feed oil, it could flood the shift solenoids (example,4L80E)
BWsonnax

* Tue, 18 Nov 1997 11:21:51 EST
BWsonnax,
In your reply on this subject you say "numerous shops are blocking the regulator valve to max. PWM".
Could you elaborate on how they are doing this ?
Ron Widing
Widco Transmissions
Griffith, IN

* To clarify...blocking the "converter regulator valve in the valve body" will allow full line psi to flow to the apply circuit. Blocking it means...the two spooled valve must remain towards the end plug and clip on the 4L60E.
If you examine these valves they are set up similar to a line pressure regulator. They have a boost/isolator plug and a balance circuit. Keeping the valve in the high flow position allows higher apply psi. to the converter. (This pressure must flow through the converter TCC valve in the pump after the regulator valve.) I'm NOT a fan of putting Band-Aids on problems, such as this procedure. But at this time your options are limited.
BW

[cybercide]

Re: 4L60E TCC Valve - blocking the valve vs. sonnax kit

Hey CDNFB

I had emailed you a few days ago asking if you could send me the rest of the info you had, I think it was a bigger PDF with pictures? I want to get a better idea of what I'm getting into. Thanks in advance!

[CDNFB]

Re: 4L60E TCC Valve - blocking the valve vs. sonnax kit

So your the one who asked for the figures. My wife mentioned that I had an E-mail at home. But I've been pretty busy and didn't get to it. Sorry about that.

Well I thought I had an understanding of the Torque Converter Clutch lockup circuit, but this blows it out of the water:

The regulated PWM converter apply circuits are not routed oil from the pressure regulator valve as in "the good ole'days. The 4L60E pwm oil circuits are not correctly illustrated. If you work through signal and apply circuits you will see this

Sound like the PWM further modifies the oil pressure from the TCC valve. I thought that the TCC valve was the last control before the Torque Converter Clutch. My tranny guy told me that the torque converter clutch is constantly being applied at all different times and between different gears, based on conditions and that the engagement could be varied (PWM).

To be honest with you, it would take less time to do the Sonnax mod then it would be to try to understand this PWM thing. I've got some researching to do.

I'll send those figures to my write up right away.

[cybercide]

Re: 4L60E TCC Valve - blocking the valve vs. sonnax kit

I dunno but the more I tried to read into it the more I thought my brain was going to explode LOL I really don't know jack about trans and trying to read up on this stuff just proved it more

I appreciate the email! going to take a look at that later, not in a learning mode right now...