700R4 trans behavior

[kpdalton]

So my truck has the 700R4 trans and it has odd shifting behavior. If I take it easy it drives fine, if I give it a fair amount of throttle it shifts odd and almost feels like the transmission is slipping. Everything is new and rebuilt so I know its not that. I know it needs torque converter lockup kit and the cheapest I've found is $170 at jegs. But from what I read this will only take care of any issues at 40mph or greater & when in overdrive.

I'm wondering if anyone has had this issue and can offer any insight. Its almost embarrassing when its shifting funny which is anytime I try to get on the throttle.

[NEWFISHER]

How did you adjust the TV cable? Did you buy a new TV cable and not a used one? How is the fulcrum set up at the carb? Is it injected? Pic's of the linkage would help.

[kpdalton]

Its fuel injected. cable seems to be adjusted fine. WOT it is tight. A little loose sitting as it is now.

[99-LS1-SS]

Here is a good (and long) article explaining the TV cable and how to set it. Not sure if you need it or not but here it is.
http://www.tvmadeez.com/article/index.php

[LEEVON]

Others will chime in, but the the Cliff's notes are that the TV cable is not a kickdown cable, it controls fluid pressure. DO NOT DRIVE until this is resolved, you will quickly burn up the transmission. There are specific methods to adjusting this cable but the only 100% positive way is with a pressure gauge. It's easier than it sounds, the gauge is about $30 and there is a port on the driver's side that has a plug you can directly tap. Provided your linkage is correct and the plunger and spring are working you should be able to make a simple adjustment. I'll let the others chime in about how to do that and you will get a wealth of information by searching "TV" and "700R4" on this site.

As for the lock-up it can be done anywhere from free to $170 but that's waaay too much to pay. You simply need to provide 12 volts to the 4th gear pressure solenoid. Outside of the transmission there are different ways to accomplish this, some choose to use controllers (expensive) others brake switch and a vacuum switch but it's just a single circuit. Inside the trans your wiring may be different, but the bottom line is that a solenoid needs to activate to close the fluid circuit under the right conditions. Some research on this will get you going.

[NEWFISHER]

This is what helped me from daves Performance, it sounds like a geometry issue:
1.093-1.125 from CL to CL on the carb, approx 20* to the rear.
TV cable bottomed out at WOT.

That will keep the trans alive and more often then not you will have to back off the adjustment a click or two.

It is better to be slightly too short on the CL to CL measurement than too long.
Too short is less throw, so it keeps the TV plunger in the sleeve further in (higher pressure) at idle with the same WOT setting.

Too long and you can get a situation where the plunger is too far out and you have no line rise on throttle tip in.

I just did a 700-R4 a few weeks back in a '55 Chevy. $100K+ car and the high dollar trans was cooked because the high dollar RamJet 502 linkage wasn't properly setup. I caught it when I went to supervise the install.

The problem was the TV CL to CL was too long at about 1.45 inches. This means at idle, the TV plunger was too far out and on initial throttle tip-in there was no line rise.

On a stock 700 or 200 trans line pressure in Drive at idle should be 65-80 lbs. On a modded trans it can be as high as 90 psi, anything more than that and you will often have 2nd gear starts.

This isn't much pressure and it should INSTANTLY come up anytime the throttle (cable) is moved. If you gently pull the cable and there is no movement on a pressure gauge, FIX it.

90 psi of line isn't going to hold the clutches engaged behind a stout engine, even in a light car.
On take-off the converter is multiplying torque about 2.0-2.5 times the crank torque.
So lets say the flywheel torque at 1000 rpm on the 502 Ramjet is 275 lbs. The input shaft on the trans will see 550 lbs of torque leaving a stop light at minimum throttle.
If the pressure doesn't spike, then the clutches slip.

The problem with a too long CL to CL measurement is,
at WOT all is OK.
At every throttle angle less than WOT, the error becomes greater the closer to idle you get.

So effectively, as long as you went WOT every time you moved the throttle, the trans would be OK, but it's actually the mild stop light to stop light driving that would kill it in that scenario.

[NEWFISHER]

Have you tried swapping your throttle and tv positions on the linkage?

Once corrected, please post what fixed it.

[kpdalton]

Sounds like before anything is done I need to hook up a pressure gauge. Also, I had someone press the gas peddle all the way down and both throttle and tv cable are maxed out. The throttle cable and TV cable are both loose at (engine off) position. Let me just say, in overdrive is when it gets wacky and I think the torque convertor lockup will fix this. I need to drive it in 3rd and see how it does. Odd thing is, going downhill when I get on the throttle it does great (if this is any indication of anything).

As far as swapping the throttle and tv positions, I don't think thats possible since the throttle pulls in and the TV gets pulled out.

[NEWFISHER]

ok, now knowing it only happens in 4th....it may be what they call "shuttling" of the converter. When you have a lock up converter , but no command to lock up it will hunt or shuttle. I used TCI kit with vacuum switch and couldn't be happier.

[LEEVON]

It's common that the throttle pull length and TV length don't match. It may be bottomed out at full throttle, but where does it return to at idle? The gauge will tell you this. I'm not sure about your throttle body's throttle cable mount, but on several carbs I've had to move the mounting point to give it less pull and thereby match up better with the overall stroke of the TV. Like Newfisher said, just a little (1-2 psi) pressure at idle is needed, so immediately off idle you have pressure rise and then at WOT the plunger should be bottomed out. What happens in gear and at part throttle, etc. should be confirmed with the gauge against 700R4 pressure tables. There is a copy of one on the forum somewhere.

[Atomsplitter]

Here's some info on the bracket geometry required.