Thanks guys. Looks like I have a little more homework to do. I'll keep ya posted.

May I suggest you take another drive with your new information and start from scratch. See if you have 4 shift points from a stop, 1to2 2to3 3toOD and TCC which is just a slight bump and a small drop in rpm. If you monitor pin F you can see if TCC is commanded. The command to lock TCC is just one part needed. You must be at a certain speed and it must be steady. The throttle position sensor must not be erratic. There are other "things" that must happen plus the Command to get TCC.
Is your speedometer working correctly ?
Is your avg fuel mileage working correctly?

Just because you have an overhauled transmission does not mean it guarantees perfection.
.
https://cimg9.ibsrv.net/gimg/www.cor...7932b98cd2.jpg
https://cimg0.ibsrv.net/gimg/www.cor...312cf66865.jpg
https://cimg1.ibsrv.net/gimg/www.cor...948e8eca4f.jpg

Not sure where this chart is from but appears to have some errata. In your last slide, step one says "depress brake pedal, light should go out - does it?" Step 2 says "release brake - light should go out". The light can't go out if its already "out".

There's 'NO ERROR' - it's an other step. BUT the OP has an '85 and he should be very familiar with the TCC Diagnostics used for '85. The CHART is similar and also has a ***NOTE: Before Replacing ECM checks!

*** An '85 FSM has diagnostics for checking ECM Drivers I believe.

https://cimg1.ibsrv.net/gimg/www.cor...1a0124bb36.jpg

I believe the difficulty is in the details.

Depress brake pedal light should go out.
Release the brake pedal (I assume the light comes back on until the next step)
ground diagnostic terminal light should go out.

The difficulties are 1.) The OP has an '85 with a very different ECM 2.) Screen Captures generally don't post well. That's why I generally ask an OP if they have an FSM and refer them to the appropriate section and avoid similar experiences. I posted the '85 CHART just because it mentions the ECM Diagnostics. The OP has mentioned in the past his vast knowledge so ..........

Charts are good but I have a device that plugs inline with the 3 wire transmission cable. It has three indicator lights that test under real world driving conditions. If conditions are all met for TCC, all three lights are on while driving. Touching brake and observing the lights and tach narrows things down in quick order.

My 93 700r or 4L60 been told the same trans by X-perts .I had problems with mine first thing the shop checked was the trans pressure, if pressure not right nothing works right, mine has a pressure port on the upper driver's side. I had to change out the Governor. FIXED it .

TH700R4 transmission slipping and od problems.
 

Hello,
I have a 1989 Corvette C4 with the TH700R4 transmission with some problems.
First of all, when I´m driving in 3rd gear and give it gas to kick down, it kinda kicks down but it just stays at 2200rpm even though the speed is increasing, the rpm stays at 2200rpm until I let off the gas for a second, seems like it will not completely engage into 2nd gear. When I use the manual position for 1st and 2nd gear, it works completely fine and stays locked in the gears no matter how much or little gas I give it.

I have replaced tps, maf and iac. I have also adjusted the TV cable.

Then onto my second problem, the overdrive (4th gear). The overdrive never engages when I´m on the throttle, but when I lift off and coast it engages overdrive, until I get back on the throttle, then it shifts down to 3rd again.. And if I shift manually back to drive when I´m coasting in overdrive, I can feel it shifting down to 3rd.

I have recently replaced the transmission fluid see if that would help, but nothing changed.


Thanks in advance to all answers/replies!