TV (Throttle Valve) Cable Adjustment

Tom Lentz

After mentioning it on the list, I've had a few people ask me about adjusting the TV cable, what it is, and how to do it. I thought I'd post instructions.

Okay, here goes...

The TV (Throttle Valve) cable is a cable used by the TH-200-4R (and TH-200 I think) tranny to control shifts, kick-down, line pressures, etc. The TH-350 has a vacuum line to accomplish much the same thing.

The cable is attached to the throttle on the driver's side of the carburetor. The lower cable is the throttle cable; the upper one is the TV cable. The adjuster button is toward the inside of the cable, just in back of the mounting bracket (mine's really hard to push in, almost takes two hands). In front of that, where the cable comes out of the bracket, before it attaches to the throttle linkage, there's a square plastic part with "ridges" on it. Push the button in and push that square plastic part back in (towards the firewall) so that it's flush with the bracket. That's "tight"; "loose" would be a lot of the square part exposed. The TV cable controls the hydraulic line pressure in the tranny and how early/late the tranny shifts. Tighter, and you get higher line pressure and firmer, later shifts. Looser, and you get less line pressure and sooner shifts. Way too loose can damage the tranny because the lower line pressure won't hold the clutch packs and they slip.

After it's pushed back tight, open the throttle wide (quickly) and let go. I use the throttle on the carb, but it probably would be more accurate if you used the gas pedal (theoretically, floored on the pedal should be the same as wide open by doing it manually, but the universe isn't perfect). You'll probably get 3-6 "ridges" exposed after setting it.

For performance use, now push the button in and move the square part of the cable back ONE ridge. If it pops back out when you use the throttle (usually doesn't), then oh well, figure it was meant to be that way. If it doesn't, then your tranny will shift at a slightly higher RPM and slightly firmer. Drive it for a while and then push the cable back a notch, you'll notice!

Tom