bbond105

You will need the A74741QA or do like Tayto said and just flip the inner stock tcc valve.

tayto

A74741QB is for 2007+ with CANBUS. Some 2005/2006 models had CANBUS as well, check​​​ Fitzall's instructions. I thought your core was a 2004, so you should need A74741QA. I like that the Fitzall has o-rings it should seal up a worn bore better. I am guessing with the correct valve it should vac better. You are vac checking at 2 locations on the TCC correct? i believe one is the regulator valve and then the other is the iso valve. I haven't used the fitzall valve yet, only flipped the iso valve.

2BFAST

iTrader: (11)

Did you install the Sonnax forward abuse valve kit?

dixiebandit69

Yes, why?

bbond105

Forward abuse valve: 16" hg

Kit should have help rase this vacuum.

dixiebandit69

Well, it did a little bit.
I can check it again; the placemat material I'm using can be kind of difficult to work with.
What do you use?

bbond105

I am embarrassed to say that I haven't taken to time to build a test set up yet. I found where Sonnax has a test block and mat for about $18
Sonnax Part No. SWAT-P1

dixiebandit69

Okay, I retested that valve, and the best I could get was 17.5" hg.

I'm still going to run it.

Here's how it looked while I was testing it; maybe MaroonMonster, Vortec, or someone else can point out if I'm doing something wrong.

tayto

I used this on my DIY vac rest rig. even went to the hose supply place and bought the push connect fitting and hose like the sonnax unit.

2BFAST

iTrader: (11)

With everything else you have corrected you will be fine with this. Your reverse abuse results are great and is tied into the 3rd accum circuit.

Was just asking is all as bbond mentioned it still seemed a little low as those kits really improve things from what I have experienced.

mrvedit

This is a great and informative thread that covers many of the questions that often occur during a rebuild.
The vacuum testing is a very useful topic which has only been discussed here starting recently.
If anyone is up to it, please create a list of links to the Sonnax (or other) pages which show exactly where and how to vacuum test each circuit in the valve body.
I found this: https://www.sonnax.com/tech_resource...uum-test-guide
But is there more?

Also, I see that the Sonnax VACTEST-01K vacuum test stand is listed on Jegs for only $157 but has a 1-month shipping delay. Summit has it in stock but at $248.
Harbor Freight has a 3CFM vacuum pump for $150. (But its their cheapo Pittsburg brand.)

bbond105

If anyone is interested in building their own vacuum test kit on the cheap you need to check out MaroonMonsterLS1’s thread.

DIY Vacuum Test Valve Body - LS1TECH - Camaro and Firebird Forum Discussion


Also check out this video




Jegs has the Sonnax 77754-VTP 4L60 Vacuum test plate for the 4L60e for $123. It’s not a necessity but it looks like it would make the job easier.

mrvedit

UPDATE - I ordered the Sonnax VACTEST-01K two days ago at the low JEGS price and despite their website saying it wouldn't ship until June (in 30 days) it showed up today!

dixiebandit69

Pfft. Lucky. I just got an email a few days ago that Jegs put the Pressure Control Valve reamer on backorder until June!

In other news, I got the Fitzall A74741QA. Here it is next to the A74741QB, in case anyone else is as confused as I was. ("B" on top, "A" on bottom)



I've got good news and bad news about the vacuum test results:

The result of the passage CLOSEST to the edge of the valvebody was 24"! I guess the O-Rings will do that for you.

Bad news: The results for the inner isolator valve were somehow WORSE than the initial test: 11.5" was the best I could get, and I was screwing around with this thing for awhile to optimize the reading. I have no idea how I got the 14.5" number the first time.

Here's a picture of the passage I tested, in case anyone has any criticisms:




Question 1: Since I really, REALLY, REALLY don't want to buy another special Sonnax valve, plus tools that I will probably only use once, is there any way that this could be passable? I really tightened up one side of the circuit.

Question 2: Since the Fitzall TCC valve pretty much blocks the isolator valve inward, is there any way that using some kind of sealant on it could be feasible?

Or what if a groove was cut into the Isolator valve, and an O-ring installed?

How do the pros out there handle this situation?

2BFAST

iTrader: (11)

Im def not a pro, but in my opinion for the application your using this for, and what you have already corrected, I think you will be ok. The extra o ring idea is intriguing though?

dixiebandit69

I was looking over the hydraulic diagram in my GM manual, and it looks like the isolator valve is just to counteract the TCC valve, and some leakage/ bypass is normal?

Maybe Maroon or Vortec can school my *** on this.

MaroonMonsterLS1

the isolator valve vacuum test doesn't matter when using the fitzall valve
or when flipping the stock valve setup around for "on/off" lockup

it will just leak the TCC PWM signal oil to exhaust. It's an orificed and pwm controlled leak so it won't be enough volume to matter at all.

dixiebandit69

THANK YOU, MaroonMonster!

dixiebandit69

I finally got the Sonnax Pressure Regulator valve reamer a couple of days ago; I used a variable speed drill at work to do this (apparently the speed of the bit is critical, and I currently only have a non-variable drill).
I used some Caterpillar No. 46 hydraulic oil for cutting fluid. It went pretty easy.





Results: 21.5" hg, a solid 10" improvement!

If you had told me ten years ago that I would be getting excited about vacuum readings, 1) I wouldn't have known what the hell you were even talking about, and 2) I wouldn't have believed you.

matermark

Does that reamer only do where that valve lands ride? I just bought the oversized valve that doesn't need reaming...