I finally got the tcc lockup working in my 700R4 trans in my 86 Caprice, after driving it well over a year without it working. The shifts seem to have improved quite a bit within a couple days of driving it with the lockup working again. All shifts are a lot more firm than before. Fluid was not dumped when it was fixed cause it was an external wiring problem. Just wondering if I should change the fluid, if theres any chance that the torque converter locking after not locking for so long could do anything to the fluid? It was changed not long ago cause of being overheated pretty good trying to get through heavy snow, but I might drain it again and add synthetic. Just wondering what the lockup working again, could have done to improve shift feel besides lower fluid temps. It seems to shift better whether its hot or cold?
trans experts please
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MolaKule
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I would do at least a pan drain or suck it out through the dipstick since it was overheated at one time.
Synthetic ATF or "Blend" always improves cold weather shifting in my experience.
Synthetic ATF or "Blend" always improves cold weather shifting in my experience.
There are two solenoids that can cause this problem with GM transmissions (at least up until at least 1994.) It was around a 150 dollar fix then.
I wouldn't say it was overheated badly on the current fluid, I changed it since the overheat, but highway driving at 70mph with no lockup for the past 10k miles or so since the fluid was changed will definately have run the transmission hotter than it should be.
^^Wasn't the solenoid actually, just a vacuum switch on the firewall, bypassed it somehow so it works without it.
If you plan on keeping that car, do drain and clean the pan, and refill with new Dexron-III ATF. Install a drain plug on the pan while it is off, and drain and refill every 10,000 miles until you have bright cherry red ATF.
If you really want to do your transmission a favor, clean it with Auto-Rx
www.auto-rx.net
Ken
If you really want to do your transmission a favor, clean it with Auto-Rx
www.auto-rx.net
Ken
It is pretty well bright red right now anyways, and has been the whole time i've had it.
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