Q: I have rebuilt a 1984 Suburban 4×4. I replaced the 350 with a 402 big block with 10:1 compression, and rebuilt a 700R-4 transmission with a Corvette servo.
The problem I have concerns the transmission. It shifts fine if you hammer the throttle or in open highway driving. But if you accelerate too slowly, the transmission will not shift from second to third until 3,200 to 3,500 rpm, and sometimes between 3,500 to 4,000 rpm. I have to feather the throttle to get it to shift.
Is the problem an improper detent cable adjustment? If so, what is the proper way to adjust the cable? Is the cable travel distance wrong on the carburetor? The truck has no computer, and I am using an adjustable throttle cable bracket with an automatic transmission kickdown.
A: The detent cable on a 700R-4 is more commonly known as a “TV cable.” As you have discovered, if this cable isn’t adjusted properly, the transmission won’t shift properly, if at all.
Here’s the procedure for adjusting the TV cable:
- Depress and hold the metal reset tab.
- Move the slider back through the fitting, away from the throttle idler lever, until the slider stops against the fitting.
- Release the reset tab.
- Test drive.
You may have to do the reset procedure more than once to get the transmission to shift properly. If this doesn’t cure the problem, then you’ll want to have a good transmission shop check the output pressure on the transmission pump.
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