700R4, great when cool, early shift when hot
10-10-2017, 09:06 PM
#1
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Car: 1990 Firebird, 1992 S10 V8
Engine: 383
Transmission: 700r4
Axle/Gears: 3.73
700R4, great when cool, early shift when hot
Long time listener, first time caller!
I have a 90 firebird with a 383 in front of a 700r4. The 383 is carbed with correct geometry on the TV cable, however I am having a few issues that I am wondering if they are related.
First and foremost, the 700 shifts perfect when it is running cool. Shift points are correctly spaced, crisp, and 4th kicks in around 45 at light throttle. After about 20 minutes, the shifts start to stack on one another. It will kind of slop into 3rd and fourth while still accelerating from a light or stop sign. I have a brand new aluminum racing radiator and trans cooler which behind an electric cooling fan and sees lots of airflow, so overheating trans fluid just doesn't seem to make sense to me. They are running through rubber lines however, and they run somewhat near the headers. I will put a temp gauge on the lines, both supply and return from the cooler this weekend to verify the in and out temps.
The other issue I am having which I don't think is related... but I have been surprised by less... is the trans WILL NOT detent with throttle pull on the TV. This does not matter if the engine/trans is hot or cold. It correctly downshifts with the governor when the car speed slows, but it will not kickdown without dropping the gear manually with the B&M shifter.
I am dropping the pan to install the B&M shift improver kit this weekend as well, and will do a new filter when the pan is off. I have been reading throughout these forums about possible debris or blockage in the TV plunger or in the lines, but is there anything else I need to look for? Would this also cause the trans to get hot and lose its shift points? This is a 1992 4l60 from a Regal which I had sitting around.
Any help or past experiences of similar problems would be great.
Thanks.
I have a 90 firebird with a 383 in front of a 700r4. The 383 is carbed with correct geometry on the TV cable, however I am having a few issues that I am wondering if they are related.
First and foremost, the 700 shifts perfect when it is running cool. Shift points are correctly spaced, crisp, and 4th kicks in around 45 at light throttle. After about 20 minutes, the shifts start to stack on one another. It will kind of slop into 3rd and fourth while still accelerating from a light or stop sign. I have a brand new aluminum racing radiator and trans cooler which behind an electric cooling fan and sees lots of airflow, so overheating trans fluid just doesn't seem to make sense to me. They are running through rubber lines however, and they run somewhat near the headers. I will put a temp gauge on the lines, both supply and return from the cooler this weekend to verify the in and out temps.
The other issue I am having which I don't think is related... but I have been surprised by less... is the trans WILL NOT detent with throttle pull on the TV. This does not matter if the engine/trans is hot or cold. It correctly downshifts with the governor when the car speed slows, but it will not kickdown without dropping the gear manually with the B&M shifter.
I am dropping the pan to install the B&M shift improver kit this weekend as well, and will do a new filter when the pan is off. I have been reading throughout these forums about possible debris or blockage in the TV plunger or in the lines, but is there anything else I need to look for? Would this also cause the trans to get hot and lose its shift points? This is a 1992 4l60 from a Regal which I had sitting around.
Any help or past experiences of similar problems would be great.
Thanks.
Last edited by GM Robotics; 10-10-2017 at 10:01 PM.
10-12-2017, 04:41 PM
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Re: 700R4, great when cool, early shift when hot
Use the TransGo Junior Shift kit with the Corvette servo, larger .471" or .500" main boost valve and the .296" intermediate/reverse boost valve and drill the separator plate out to my specs depending on the stall and diameter of the torque converter, what is done to the motor, rear end gear ratio, and how you drive. I can give you the specs when needed here. As long as the transmission is still in good shape, (little to no clutch material in the bottom of the pan) this kit will help extend the life of the transmission. Install the temperature gauge in the top line going back to the transmission, to see how good the cooling system is working. You want 155F - 180F temperature range. I do not like the B&M kits as they do not solve the TV problems among other things. If I can be of help let me know.
10-12-2017, 06:00 PM
#3
Re: 700R4, great when cool, early shift when hot
[quote; The other issue I am having which I don't think is related... but I have been surprised by less... is the trans WILL NOT detent with throttle pull on the TV. This does not matter if the engine/trans is hot or cold] I'm not sure what you mean by "will not detent with throttle pull on the TV" Have you adjusted the TV cable properly? https://www.thirdgen.org/detent/ Here is a good video to watch on how to set up a carb bracket. https://video.search.yahoo.com/searc...81d9e11c3bb327
Last edited by red rock; 10-12-2017 at 06:09 PM.
