Paxun

Bought this mystery transmission for a rebuild project in my '89 GTA. Followed the ATSG manual religiously given this is my first AT rebuild. TV cable is absolutely adjusted correctly. My 4th gear is at 35mph with 3.27 gears and stock F-body tires/wheels. I believe stock it should be at 45mph.

Called two transmission shops and both told me they have no interest in looking at this thig for me, one shop said he knows nothing about a 700R4/4L60 while the other shop was kind enough to implicate the governor. Thinking about a governor recalibration kit, but would appreciate some more input before I start messing with the governor. I think this trans is from a 1990 truck based on the stamps.

Anyone in here know these 4L60/700R4s well that could make a solid suggestion?

FranksCustomTrans

First does the TV max out at WOT? 327 is within the 700R4 gear options over the years. What does the line pressure look like with tv fully pulled.
You can raise the shift points in a number of ways , Gov or using the sonnax TV spring or a stiffer TV limit valve spring.
If your pressures are good 60 psi or so at idle relaxed TV and 160 or higher at max TV around 1200 rpm. I would go with gov recalibration, But there is another easy trick , This thread may be helpful https://ls1tech.com/forums/automatic...l#post20562282

Paxun

TV cable is maxed out at WOT, but is adjusted all the way forward.

Line pressure with TV pulled (idle; 650rpm) is 190psi.

Idle pressure in P is about 78psi at all engine speeds. NOTE: I used a 5 or7 vein pump if I remember correctly.

Reverse pressure is 120psi with no change at various engine speeds.

When I go to low gear manually pressure hits 190ish at idle (bouncing around 170-195). Pressure is the same when I manually shift into second, BUT when I manually shift into third the line pressure goes back to 78ish while the same for OD.

While in D and OD the line pressure is basically 78psi and does not change much at all regardless of engine speed.

NOTE: All of these pressure readings were from a cool engine/trans; not at normal operating temp.

FranksCustomTrans

Sounds like your TV is working and adjusted properly, So I would go at GOV you can try the simple things I mention first as they are easy. Harbor freight spring kit, and if that does not get what you are looking for then the GOV reprograming kit like like from TCI
Personally I would try adding the spring it has a few of various stiffness that will fit in the cup in gov as I posted and see what the result is. For the majority of my customers looking for a smaller change 10 to 20 mph or so, It has been pretty effective over the years and it easy enough.

Paxun

Does this look heavy for a stock thirdgen with 3.27 gears?

FranksCustomTrans

Looks pretty typical for 273 to 323 of so gears , Not many options really in 700 stock gov. I would really consider doing my little spring trick while you have it out, Most find the result surprising. Or optionally you can try and find a gov out of a monte carlo ss or an old S10 2.8 blazer from the early and mid 80s if any still around . I was looking for photo of one but cannot find , The S1O one has an open weight at outside hard to describe but maybe Vortec or maroonmonster will chime in with a photo. But usually these are only needed with 373 or higher numerical ratios.
I'm also curious if you throttle body/ carb is a non stock application, The ratio of the pull on the cable also come into play and is a far more likely issue if your cable is indeed maxed out at WOT as it should be and those shifts are in expected range,

Tranzman

I agree with @FranksCustomTrans about the Governor. Here's a copy of the TransGo SK700 Shift Kit instructions, it gives a very good description of the various governors that were available for the 700-R4 on pg 3. It doesn't show the Camaro 3.73 governor though. I have one I am building now. I am documenting the weight's and spring rate/weight as I write this.
Page 8 has a very good explanation on TV cable adjustment and throttle relationship. This kit was a must have for the 82-86 transmissions in my book. They needed a lot of help in the beginning. The 87 & up got a lot of these changes from the factory. I still use a SK700-JR in all my OE or mild performance 700-R4 builds.

Paxun

Thanks for the responses. This is a 5.7 Tuned Port Injection with all original brackets at the throttle body (stock) and on the transmission. Original shifter was also reinstalled. I bought the car with a th350 AT, but I had to buy this trans to get OD back - max cruise was about 40mph.

WOT shift points are about 4200 for second and third.

Thanks a bunch, I will take a look at the TransGo instructions and mess with the springs. I believe I have the spring kit from HF. Greatly appreciated!

FranksCustomTrans

4200 TO 4600 IS TYPICAL WOT shift with the stock GOV TV spring, In your case I would start with the stiffest of the little spring that fits in the cup of the GOV valve , Note the spring whichever you use must be one that will fully collapse into the cup when compressed so it does not limit the GOV valve travel . You will note when done
the leaves on the outside will default to inside and when you pull out will flop right back when you let go.