Is it the TV Cable?

[SlicksInRain]

My 90 has the lame Th700R4 and I have a problem with it. I can drive like an old lady and it'll shift fine, but when I give it as much as 1/4 throttle it has trouble. It won't shift until much later, sometimes 25 before it changes into second gear. I have a transmission ready to install, but I was told it could be the TV cable that needs adjustment.

Also if I park it for a while and drive it easily it'll be fine again. This issue has been going on for a few months. A shop told me my clutches were shot?

What could it be?

 

[folkenheath]

Well if you have a lame 700R4 that must be a different one than a normal 700R4.

As for the TV cable, it can be adjusted by pushing a D shaped button on the cable housing on the cable bracket behind the throttle. You can slide the inner housing in clicks while pushing the D shaped button. The tighter the cable is, the harder and later it will shift, the looser the cable, the softer and earlier it will shift. But if you don't know what you are doing and adjust it wrong you can ruin your transmission in a few miles by burning up the clutches.

Also, you said it shifts later. When it does, does it shift hard, or does it shift real soft and slip into gear? Because if it is shifting later and hard that is more easily adjusted with the TV cable. But if it shifts later and also slips while it's shifting, then that is a bad sign for the clutches.

The fact that it changes when you don't drive it for a while is not good either.

 

[Greg Ducato]

It could be that the tv valve itself or the 1-2 shift valve is sticking. You can check the tv cable by rolling the throttle to the wide open position and observing that the cable is fully extended and banjo string tight at wide open throttle. If the cable is too tight, it will limit throttle travel at the wide open position and also induce a late firm shift. Since your problem is intermittent I would guess sticking valve. One thing you can try when the valve sticks is, with the engine off, to rapidly floor the accelerator pedal several times. This will push the primary tv valve plunger and spring against the rear tv valve and hopefully free them up. The valves have very sharp edges and will sometimes self clean as they stroke through a bore, but a nick or scratch from a bit of contamination can bind them up, especially at operating temperature.

 

[SlicksInRain]

It will have a late hard shift and effect the rest of the gears too. 1-2 will be 25mph, 2-3 won't be until 45 and it won't even make it into 4th/Overdrive. At 60mph the truck is roaring and I don't wanna damage it further by finding out what speed it takes to make it into forth.

Looks like I have some work to do.

If the valve is stuck how do I free it? Where is it located?

Thanks guys.

 

[ryoken]

http://www.tvmadeez.com/article/index.php

 

[British Slave]

It doesn't cost anything to adjust the cable and see if it helps.

 

[rufusbooth]

Pushing thg D shaped button on the cable housing on the cable bracket behind the throttle and pull the housing back until the throttle is being held open with the TV cable. Go into the truck and press the throttle to the floor. you will hear the cable clicking into the proper position. As mentioned the cable should be fully extended when the throttle is wide open.

That is the proper setting for your TV cable. You don't "adjust" a TV cable. If the cable is set properly and the trans is still not shifting properly then there is something wrong internally in the trans and needs investigation. If the TV cable is not set properly WILL cook the trans realy fast.

Rufus

 

[folkenheath]

Pushing thg D shaped button on the cable housing on the cable bracket behind the throttle and pull the housing back until the throttle is being held open with the TV cable. Go into the truck and press the throttle to the floor. you will hear the cable clicking into the proper position. As mentioned the cable should be fully extended when the throttle is wide open.

That is the proper setting for your TV cable. You don't "adjust" a TV cable. If the cable is set properly and the trans is still not shifting properly then there is something wrong internally in the trans and needs investigation. If the TV cable is not set properly WILL cook the trans realy fast.

Rufus

That's fine and dandy sometimes, but other times that procedure doesn't result with the TV cable functioning properly if you work with enough of them. It could be a sticky adjuster or something, but sometimes you have to tweek it a couple clicks here or there for it to work properly. Regardless it should still be tight at full throttle (without limiting full throttle). You are correct that it can damage the trans if not set correctly, especially if it's too loose.

 

[dabomb6608]

Ya i did the throttle to the floor thing on mine and it wasnt completely right. This was on a fresh rebuild to.

 

[folkenheath]

Ya i did the throttle to the floor thing on mine and it wasnt completely right. This was on a fresh rebuild to.

One of the times I have done that setup precedure, it actually snapped the plastic piece off the end of the cable around the throttle stud. I had to buy a new cable.

 

[Blue85]

If the problem is intermittent, I would suspect a sticking TV valve. But usually when they stick, the throttle position doesn't matter. If 1/4 throttle is different than "old lady" throttle, I would suspect the TV is working and the governor gear is stripped. It's easy to pull the governor out of the side of the transmission (no pan drop necessary) and examine it. The plastic gear that rides on the output shaft eventually wears out.