This is not a question as much as passing along information and what worked for me. I couldn't find very much on this topic on here or elsewhere online.

The 700 in my 442 developed a sticky throttle valve out of nowhere this week. I was able to isolate that as the cause by examining the symptoms, doing some research, and checking some other equipment on the unit (like the governor) for defects.

The issue I experienced was all of a sudden the transmission would refuse to shift until very high RPMs. There wasn't any slippage, and when it would shift, it would shift firmly, but part throttle shifts disappeared. When it first happened, I had to hit nearly 4500 RPMs before it would grab second. This is a pro-built 700-R4 behind a big block Oldsmobile, so that meant a lot of wasted rubber just trying to get into second gear. I'm lucky I didn't get a ticket.

I was resigned to letting a shop clean out the valve body when I thought of an old hot rodding trick. Being a Quadrajet guy, I've occasionally encountered the dreaded "needle and seat stuck open" issue where things get stuck and the carb keeps filling with gas. Gas leaks everywhere, etc etc. An old mechanic taught me to cut the fuel to the carb when this happens until it starts to stall out, and then let the fuel push full pressure to the carb. You can do this on a carb by kinking the line, and then unkinking it. Works like a charm.

The transmission analog I thought of was to unplug 12v to the distributor and crank the engine while pumping the gas. I have a ministarter so my engine cranks fairly fast, but my thought was the variance in low rotational speed on the hydraulic pump in the trans would be about perfect for making the pressure fluctuate widely.

So far it's unstuck the "stuck" valve twice for me this week. I tried the method where you just yank on the TV cable, didn't have any luck. Going to do flush/filter this weekend and hopefully be gone of TV woes.

YMMV, but something else to try if you find yourself in this situation.

 

Thanks for the good info. Of course I already have the valve body, and govenor out. My trans was doing something like yours. Just out of no where the upshifts got extended and when it didn't upshift and I let off the gas the trans would feel like it was in neutral. Checked operation of tv cable and tried jiggleing it while it was running. Before I tear it out I just might put it back together and give it a try.

Thx