700r4 Not Shifting

[Erik the Awful]

To be clear, we are not diagnosing your TV cable set up or adjustment from the internet but informing you how to rule it out as a possibility.

Yup. I was responding to...

If it was not adjusted correctly I would imagine it would have burnt up years ago but I will double check it.

Checking your pressures, as you said you'll do, will eliminate a lot of the questions.

 

[Samuel Churchill]

The gauge I ordered should arrive tomorrow or so. What I have done is tried more road testing and here is where I'm at. If I have the engine off, I can open the throttle wot and side step it to let the spring fling it back and when I start it up it will start shifting perfectly. If I give it say 50% throttle and get up to speed it shifts as expected, but when I come to a stop and go again it will not upshift until rpms are at the same point it was the previous run. I can repeat this, each time increasing my throttle/acceleration and it will shift as expected until I then try and accelerate slower than the fastest I accelerated where it will not upshift.

I am thinking that something is stuck to where the tv can be pulled but will not release. I can reset it by turning the engine off and flinging the throttle back. I've looked up tv valve sticking and there is not much info out there on its cause or definitive solution. The only fix I have seen is a little spring that goes in the tv piston assembly in the valve body.

To remove the valve body, should I remove the transmission, or can I do it with the trans in position? And Nick, with your Transgo shift kit recommondation, can I install part of it to cure this without the rest of the kit? I am not looking for harsh shifts on a stock truck that I drive everyday.

 

[Erik the Awful]

If the valve is sticking, get the plunger and sleeve kit. There's nothing else to the TV except the cable. The plunger and sleeve kit comes with a new spring, and that's what the TV cable is pulling against.

More Information for SONNAX 7796694K

 

[NickTransmissions]

The gauge I ordered should arrive tomorrow or so. What I have done is tried more road testing and here is where I'm at. If I have the engine off, I can open the throttle wot and side step it to let the spring fling it back and when I start it up it will start shifting perfectly. If I give it say 50% throttle and get up to speed it shifts as expected, but when I come to a stop and go again it will not upshift until rpms are at the same point it was the previous run. I can repeat this, each time increasing my throttle/acceleration and it will shift as expected until I then try and accelerate slower than the fastest I accelerated where it will not upshift.

I am thinking that something is stuck to where the tv can be pulled but will not release. I can reset it by turning the engine off and flinging the throttle back. I've looked up tv valve sticking and there is not much info out there on its cause or definitive solution. The only fix I have seen is a little spring that goes in the tv piston assembly in the valve body.

To remove the valve body, should I remove the transmission, or can I do it with the trans in position? And Nick, with your Transgo shift kit recommendation, can I install part of it to cure this without the rest of the kit? I am not looking for harsh shifts on a stock truck that I drive everyday.

You can install the TV boost valve which comes in the kit and has lands/grooves that the factory valve doesn't have - it's this feature that enables the Transgo valve to more effectively clear minor grit/debris from the bore to prevent the TV boost valve from sticking (possibly your problem). The TV plunger and sleeve are also common to wear, resulting in poor line rise characteristics, which presents as either slipping, delayed engagements at take off as well as late/harsh upshifting at highway speeds. Install Sonnax's plunger/sleeve kit to restore that part of the throttle valve circuit.

Drop the valve body, 1-2 accumulator housing and install all of the parts from the shift kit that go to those two locations. If you can get the transmission low enough, pop the servo assembly out of the case (passenger side) and install the kit's components there but I'd say that's optional, not manadatory unless you have excessive servo inboard travel...If you do, then use the gold-colored servo spacer to shim the assembly per the instructions to bring the servo travel/band clearance into desired spec (servo travel should be somewhere between .100-.175, no drag felt when spinning the driveshaft against the direction of engine rotation).

 

[Sean Buick 76]

I would start with a new TV cable, they are easy to change compared to the TV valve.

 

[Erik the Awful]

The TV cable is a real PITA to get seated in the case, but you absolutely must get it secured flush.. Lube the end before you start.

 

[Samuel Churchill]

I've taken a test drive and I can't get it to stick anymore. The problem may return but as of now I have driven around 80 miles and it has been shifting as it should.

My guess would be that there was foreign material keeping the piston from releasing and that It got worked out. If it was a burr in the pocket, then I wouldn't think it would clear out.

I do plan on pulling the valve body out and installing the aforementioned fixes, but I will probably wait until I pull the transmission and rebuild it while its out.

Thanks for all the help.

 

[NickTransmissions]

I've taken a test drive and I can't get it to stick anymore. The problem may return but as of now I have driven around 80 miles and it has been shifting as it should.

My guess would be that there was foreign material keeping the piston from releasing and that It got worked out. If it was a burr in the pocket, then I wouldn't think it would clear out.

I do plan on pulling the valve body out and installing the aforementioned fixes, but I will probably wait until I pull the transmission and rebuild it while its out.

Thanks for all the help.

If the problem returns, drop the pan to see what's on the bottom...Intermittent issues like this may be sticking TV and/or other valves which potentially indicates an abnormally high amount of contaminants flowing through the system so an overhaul may be required, depending on what sort of debris and how much.

 

[Noco Racing]

The gauge I ordered should arrive tomorrow or so. What I have done is tried more road testing and here is where I'm at. If I have the engine off, I can open the throttle wot and side step it to let the spring fling it back and when I start it up it will start shifting perfectly. If I give it say 50% throttle and get up to speed it shifts as expected, but when I come to a stop and go again it will not upshift until rpms are at the same point it was the previous run. I can repeat this, each time increasing my throttle/acceleration and it will shift as expected until I then try and accelerate slower than the fastest I accelerated where it will not upshift.

I am thinking that something is stuck to where the tv can be pulled but will not release. I can reset it by turning the engine off and flinging the throttle back. I've looked up tv valve sticking and there is not much info out there on its cause or definitive solution. The only fix I have seen is a little spring that goes in the tv piston assembly in the valve body.

To remove the valve body, should I remove the transmission, or can I do it with the trans in position? And Nick, with your Transgo shift kit recommondation, can I install part of it to cure this without the rest of the kit? I am not looking for harsh shifts on a stock truck that I drive everyday.

Hi Samuel,
I'm also new to this forum. The problem you are having is your TV valve sticking. As others mentioned before you can fix this installing a Jr shift kit from Transgo. The Jr shift kit uses a groove and double spring valve (picture # 1) Another way used in the transmission repair world is to use the conical spring from a THM125 3rd accumulator valve (picture # 2). Have in mind that if the valve is getting stuck is because with time the transmission creates small amounts of debris and because originally the valve has no spring it binds in the bore. Removal of the valve body is pretty straightforward. Wish this helps.