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**HO455** · 11-03-2022, 03:59 PM

I'm not an expert but I'm fairly certain in that year the lockup was controlled by pressure to the 3 or 4 gear circuit. Pump pressure varies with speed. That's why it unlocks when coasting as the pump isn't being driven fast enough.
There may be a pressure issue or component failing to causing the 35mph lockup. My 91 S10 locks up in 45 to 50 mph range. You might drop in to this thread and ask it it is a problem.

http://67-72chevytrucks.com/vboard/s...d.php?t=634121

And I got your prototype installed but I wasn’t able to get it to work so I pulled it out to bench test it and then my laptop went sideways. So the laptop is at my buddies for resurrection. More to follow.

11-03-2022, 03:59 PM	#139
HO455 Post Whore Join Date: Feb 2016 Location: Portland Oregon Posts: 10,891	Re: 700R4 TCC Wiring I'm not an expert but I'm fairly certain in that year the lockup was controlled by pressure to the 3 or 4 gear circuit. Pump pressure varies with speed. That's why it unlocks when coasting as the pump isn't being driven fast enough. There may be a pressure issue or component failing to causing the 35mph lockup. My 91 S10 locks up in 45 to 50 mph range. You might drop in to this thread and ask it it is a problem. http://67-72chevytrucks.com/vboard/s...d.php?t=634121 And I got your prototype installed but I wasn’t able to get it to work so I pulled it out to bench test it and then my laptop went sideways. So the laptop is at my buddies for resurrection. More to follow. __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377