Hi. I am new here, beeing from from Europe. English is not my native language, so please forgive my spelling and my way of writing :-)
I have to admit that I unfortunately dont own a LS1 engine, still only dreaming of one.
Searching the internet for some answers to my TH700r4 questions I came across this page and found out that some of the members here, have a lot of knowledge and experience with these transmissions.
Some 20+ years ago I bought a GM performance parts re-manufactured 1993 Camaro Z28 4L60 (TH700r4) transmission code 3FMM (PN 12363206) the last year you could run the transmission without a computer and also a one year only valve body as I understand.
After all these years on the shelf, it has now replaced a tired TH350 in my 57 chevy. It is hooked up to a 350 cui gen1 small block with aluminum cyl. heads and a very mild cam, almost a RV cam. Lot of low RPM torque and not so much past 4500 RPM, but still pretty fast of the line. 3.36 rear end.
The TV cable is hooked up to a Quadrajet carb. I made the brackets for the TV cable my self, following the descriptions and drawings found every where and geometry is very precisely made. The cable is an adjustable universal one.
Here comes my first issue:
When setting up the cable following the WOT method ( Throttle opened all the way, then cable adjusted so the end of the TV plunger is flush with the sleeve at the valve body ) then when engine is idling at 600 RPM there is no instant rise of line pressure when touching the accelerator pedal. with engine at idle I will have to pull the TV cable 1/4 of an inch to see rise of line pressure on manometer. Is this how the design was back in the days? or is it important to have rise of line pressure just off idle?
If both rise of line pressure just after idle, and the TV plunger to go all the way in at WOT is important, I see 3 possible ways to make that happens:
1. I could alter my brackets and geometry at the carb ( Make the stroke shorter )
2. I could adjust the cable to get rise of the line pressure just off idle and install a corrector spring from Sonnax that allows the cable to go past detent without bending the brackets.
3. Get a longer TV plunger spring, but which one and from where? At the moment I have made the TV plunger spring longer with two washers as shims between the plunger and the spring. That gives me rise of line pressure just off idle without compromising the WOT setting. BUT it also raises the genral line pressure to about 220 psi ( 180 psi without washers ) when pulling the cable with transmission in Park for testing.

What is the right thing to do?

I hope someone in here can get me some advise. ( I have got a headache from overthinking all of this )
Thanks in advance.
Claus

 

Sounds like you have a ratio issue with the cable. and it completely relaxing away from the plunger at idle. (Also is a universal cable with the lock nut middle cable make sure that nut is very tight or it will make your adjustment all over the map over and over) In any case the way I like and you make have to move the position of the stud on carb or add a small stiff spring to end of cable between attachment and cable end, I like the arm inside trans to just touch the plunger at idle and max out the plunger at wot. This can be felt with the pan on pulling the cable gently by hand till you feel the bump or with pan off. If using the small spring method just find one the right length to accomplish the goal and that fits over cable end (you can use a fishing weight to secure it old school stuff) or optionally you can work out where t move the stud on carb to achieve the ratio for the pull. Springs probably easiest .

 

Frank, thanks for answering.
The nut on the cable is tight and secure. The arm inside the transmission absolutely touches the plunger at idle, just seems to be kind of a short distance between start of line pressure rise and till plunger max out. I think moving the stud on the carb will be the best solution.
My main concern is this: Are these transmissions designed so the line pressure should rise with just a slight movement of the accelerator pedal or is it not that important?

 

The line should indeed rise almost immediately with throttle yes, But bear in mind it is not linear. The rise will increase exponentially with throttle. Less with a little and more rapidly as cable is pulled out.
Its sometimes hard to judge at low idle however, I suggest about 1500 t0 2000 rpm to check this rise. And depending on boost valve and PR SPRING SET UP , you should see 60 to 80 or so PSI at idle and 150 TO 200 PLUS AT WOT with TG boost and spring would expect to see the higher side of those at both ends.

 

Ï will keep that in mind and not beeing too focused on rise of line pressure at low idle.

One last question which is a little cryptic. As mentioned earlier I bought the transmission 20+ years ago as a GM performance parts re-manufactured transmission for a Camaro Z28.
It came with an instruction that says this:
"Throttle valve spring.
The TV spring installed in this 4L60 assembly is calibrated for engines equipped with TPI or TBI. If your vehicles engine is equipped with a carburetor, you must replace the original TV spring with the the included spring to obtain the proper shift points and shift feel"
At same time there is a hand written notice in the instructions that says " DO NOT change the spring" with out any explanation.
I could not resist trying to install the included spring, it is purple, same length and seems to be weaker. with the purple spring installed, the transmission tested in park with TV cable at wot had a line pressure at of 250 psi. I did not try to drive the car so the transmission was not warmed up. I believe 250 psi of line pressure is to much? and maybe the reason for the hand written notice of not using the spring.
Do you by any chance have an idea of what this is about? Where the transmissions when new calibrated different for TPI or carburetor?

 

250 psi cold at what throttle , Pretty impressive actually but while at the imo top of max but not to high and will likely come down when warmed a bit , The stiffer spring is going to give you firmer and slightly later part throttle shifts ,

 

250 psi cold in park 1000 rpm and TV cable pulled max. With the weak TV spring.
180 psi cold in park 1000 rpm and TV cable pulled max with the stiff TV spring.
210 psi cold in park 1000 rpm and TV cable pulled max with the stiff TV spring + 1/8 shim between plunger and TV spring. With the 1/8 shim I actually could make my bracket geometry work, early rise of line pressure and plunger all the way in at WOT. This is the only combination I tried on the road, It would shift all the gears up and down, maybe not 2-1 I had to stop testing becauce of another ignigtion related problem. The up shifts maybe came a little late to my taste, so its good to know that I can make it shift earlier with a weaker spring.
I will try the stif spring with out the shim and also change of my bracket geometry to get it shift a little earlier and maybe shimming of the TV spring is a little unconventional and could lead to some unknown problems.
i really preciate your inputs.

 

FYI, most 700R4 that used a carburetor were specific to the OE set up. The 700R4 came along as they were phasing out carburetors and going to TBI. Most carburetors are built on the TH350 detent cable design. That is why Holley, Edelbrock, Demon and ETC. require a throttle arm adapter. Even most Quadrajet carburetors were for TH350 transmissions. However there were some built for the Oldsmobile 350 that had a 700R4 actual linkage. They were 1-2 years before the 3C electronic carbs.
Here is the PDF of the handout, with pictures that I used for TV set up.
Frank is correct about: If there is slight movement to the TV cable line pressure should go up. There should be no delay and 210-220psi in D @ 1500 & TV cable pulled to WOT should be enough.

 

running the Transgo TV lineup makes for a stiff pedal on my 86 squarebody with a Qjet. I had to mess with the pedal fulcrum to get full open @ WOT. also had lots of issues getting the choke to set properly on cold mornings. i plan on going to TBI so i have just lived with it. Transmission originally came out of a late 90s Caprice cop car, was the first 700R4 I rebuilt and lived in the same car for sometime. Behind the TBI did not have stiff pedal.

OP, sounds like your linkage @ carb is wrong and/or wrong length TV cable. would also not expect the TV cable to self-rachet unless the TV line up is stock. confirm pedal to the floor makes the carb go WOT. if it doesn't address this first. with carb @ wot use a small pair of vise grips and pull the TV cable where it connects to the carb, should get like 1/32" to 1/16" if greater theb manually ratchet the TV cable 1 click at a time until all play is removed. now retest at idle and see if you get instant pressure rise.

can you share pictures of your linkage?

 

Thanks to all that replied, trying to help me. Just want to share how I solved my problem for future reference, in case it can help other with the same issue.
The TV plunger spring that comes with the Sonnax 77966-94K kit solved my problem. Instant pressure rise just past idle speed. My throttle geometry seems to be close to perfect.
The spring from the Sonnax kit is a little longer than the springs that was supplied with the transmission.

 

Thanks for the update