transmission shifting problems?

Has the check engine light come on? Also, as far as the trans, it may be a shift solenoid. Let me know about the light. These guides can help

https://www.2carpros.com/articles/automatic-transmission-problems

and

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing


Please run down these guides and report back.

The check engine light has come on a few times but it always goes off within a day, usually within an hour or two. I took it to an auto parts store to get it read one time but it had cleared itself by the time I got there and they couldn't get any readings.

Anything I say without a code is a guess. You need to get it scanned before the light goes out. However, I'm surprised the code wasn's stored in the computer.

Guesses are welcome since the CEL rarely comes on (this problem has been ongoing for quite a few months).

Personally I've been leaning towards a faulty TPS and am considering replacing my whole throttle body.

I would say the TPS. But I hate to see you spend money and not be right.

it wont shift into overdrive I can push the button on the gearshift to take it out of overdrive and it will go but at a high rpm and if I don't push the button and leave it to normally shift it quits pulling

It sounds like you have a computer control issue. If you can manually make it downshift and upshift by operating the button on the lever then the computer is not seeing a need to downshift from overdrive into drive. Check your fluid for darkness or a burnt smell and if it is have the transmission serviced first

I have had the automatic transmission solenoids all replaced because of a P1747 code now I’m getting a P0755 code. And won’t shift into 3rd or 4th. Could it be a bad shift solenoid or wire harness? The truck was in Oklahoma and now it’s in Arizona. Could wires be bad from the road salt?

Yes. This could either so the only way to know is to run through this testing. It is unlikely that you got a faulty part but the fact that you have a new code after you replaced it, I would just go ahead and see if they would warranty the solenoid. As long as you bought it from a parts store they should take it back with no issues.

Otherwise we need to go through this testing and find out what the issue is.

Good evening,

I attached a wiring diagram for you to view.

https://www.2carpros.com/articles/how-to-check-wiring

Verify power to the solenoid in the flow chart that was posted to be sure there is power for it to work.

https://www.2carpros.com/articles/automatic-transmission-problems

Roy

Originally I thought the transmission was slipping but have added a re-conditioner to my fluid and it certainly is not slipping, Peels rubber and never misses a beat. I am unsure if the torque converter is bad or if it could be a modulator valve. When the transmission fluid is cold it does not like to shift out of first gear, I can manually shift it out and it will cycle through all the other gears just fine. kind of sounds low when in fifth but it is okay. If i take off fast without giving the transmission time to "think" something squeals/ screeches behind the dash, or at least it sounds like it is behind the dash. All in all it seems like it just shifts high coming out of first gear. oh and sometimes the transmission shudders which I have heard is the torque converter. Any expert advice?

A shuddering torque converter is usually caused by using the wrong transmission fluid that does not have enough of a specific additive. To verify that, first be aware the shudder usually only occurs during initial lockup, although my daily driver does it continually, once warmed up, at around 35 mph. You will not feel the shudder below about 30 mph, not unless the transmission is in the highest gears, and not until the engine is warmed up. You should also not feel it at speeds higher than about 50 mph.

When you feel the shudder, hold the accelerator pedal perfectly steady, then lightly tap the brake pedal with your left foot. Doing that initiates an unlock and the shudder will stop for two or three seconds.

A failing torque converter can cause the same symptom, but it is very much less common than using the wrong fluid. A failing torque converter will typically cause shuddering at higher speeds too.

As for the rest of the symptoms?

it shudders whenever there is a load. like going up hills and such, sometimes while going through the gears.

I have never heard of the wrong fluid type causing the shift timing problem, or failure to shift. Your transmission doesn't use a modulator valve. It is computer-controlled. There is really very little you can do unless you have access to a scanner. The place to start is by reading and recording any diagnostic fault codes. If you find any that are related to the range sensor, (formerly the neutral safety switch), those must be addressed first. Incorrect readings from that sensor will cause the computer to be confused and will likely prevent proper operation. Once the range sensor is verified to be working properly, if the shifting problem is still there, you need the scanner to perform tests on the shift solenoids. That can tell you right away if there is an electrical problem, as in a cut wire or corroded connector terminal. That will also tell you during a test drive if there is a mechanical problem associated with one of the solenoids. That would be seen by the a change in which solenoids are being commanded on but no gear change occurs.

Given the intermittent nature of the problem, you might want to inspect the connector terminals for the range switch first. It is located by the shift lever on the side of the transmission.

I noticed it takes longer to shift into 3rd when its warm and now my OD light flashes at times.

It could be just a shift solenoid, but if the OD light is flashing, you need to have the computer scanned. There will be a code that identifies where the problem is coming from.

Let me know what you find.
Joe

Thanks for the reply back as I stated, I took it to amco and they said its internal and they would have to pull the Tran and that would require them to replace parts along the way. They gave me a quote of around 2100.00 to 2500.00 to start and were not sure what the problem is.

Isn't that interesting how they can quote a price and not know what is wrong with it. Let me know what you find.

I just had to replace the heater core in this truck (wow what a job). But at the end of job I wound up with an extra part. The "Transmission Shift Relay". I cannot find where it hooks up. Could you please help? Thanks so much.

Hello, I'm Danny.

The transfer case shift relay module is located behind the center of the instrument panel. I've attached 2 pictures showing its location. The 2nd picture I blew up larger. Hope this helps and thanks for using 2CarPros.

1-2 shift extreme hard (slams) 2-3 refuses (like it kicks out of gear until revved then slams. this happens after warm up. periodically will function fine when cold or for a time . read codes P0500 vehicle spped sensor fault. changed two times to be sure it was not the problem.

Good morning,

I attached the flow chart for the 500 code. It is DJ1.

As far as the shifting, it could be the valve body from dirty fluid.

https://www.2carpros.com/articles/automatic-transmission-problems

Did you change the oil/filter in the transmission yet?

https://www.2carpros.com/articles/how-to-service-an-automatic-transmission

Roy

i have checked all the wiring for cracks, breaks, dirty connections. fluid seems clean but i will give it a try and hope for the best. thanks

You are welcome.

Always glad to help.

Keep us updated.

Roy

It has problems shifting. When i let off gas sometimes that helps it shift. when it is cold it seems to run okay. Within 30 minutes it will start acting bad. I feel this is one of the solenoids on the transmission. It seems there are quite a few. I pulled the oil pan to change the fluid. No metal particles or bad smell. For 250,000 it looks unbelievably clean. Is this something that a scan tool will find for i will buy one. trying to limit expenses do to layoff thanks to our economy. Any help would be appreciated.

I have seen the pressure regulating solenoid cause this issue. Here is what is it used for


DESCRIPTION
The Electronic Pressure Control (EPC) Solenoid is a Variable Force Solenoid. The VFS-type solenoid is an electro-hydraulic actuator combining a solenoid and a regulating valve.

OPERATION
The EPC solenoid supplies Electronic Pressure Control which regulates transmission line pressure and line modulator pressure. This is done by producing resisting forces to the main regulator and the line modulator circuits. These two pressures control the clutch application pressures.

CAUTION: The electronic pressure control pressure output from the variable force solenoid is NOT adjustable. Any modification to the electronic pressure control solenoid will affect the transmission warranty.


This guide can help as well

https://www.2carpros.com/articles/automatic-transmission-problems

Let us know

I had to change out the pressure control solenoid cost me 78.00

When i start driving the truck seems to be in third gear and will not down shift on its own, if i manually shift it down and start out in a low gear it does fine.

I believe the transmission defaults to third gear if the transmission fuse is blown, so check that fuse.
I see it as fuse U in the engine compartment fuse box. Hot in run/start.
And a fuse I same fuse box. Hot at all times.
Correction, I think that blown fuse and default must be for later years since it appears those fuses feed a relay and also feed the PCM, so it would appear you would have a lot more problems than just the transmission.
I suggest you retrieve the trouble codes.

i have checked all the fuses.

Correction, I think that blown fuse and default must be for later years since it appears those fuses feed a relay and also feed the PCM. so it would appear you would have a lot more problems than just the transmission.
I suggest you retrieve the trouble codes.

Will not shift until it reaches at least 4000 rpm?

Is the trans fluid clean and full? Has the check engine light come on? Does it do this in all gears? It sounds like you have a partially clogged catalytic converter which will low vacuum making the late shifts here is a guide to confirm the issue.

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

Please run down this guide and report back.

Yes. Changed the fluid a week ago. Does it in all gears. Engine light is on.

Have you checked for transmission trouble codes? It sounds like a TCM problem, but we need codes or it becomes a guessing game. Also, 95 was a transition year. Does the truck have an OBD1 or OBD2 system?

OBD1.. Haven't been able to check for codes yet. What is TCM?

4x4 truck is staying in second gear when driving to and from school.

The TCM is yet another computer. It stands for 'transmission control module

That is a transmission EPC solenoid / circuit fault. If the EPC (electronic pressure control) solenoid fails, the system will function in a fail safemode with very high line pressure. The result will be harsh engagements and shifts. Keep in mind, the EPC may be fine and there could be a wiring issue. I have seen many harness connectors that were bad or corroded.

Hi,

Do you have a check engine light on? If so, please have it scanned for codes because there could be a number of causes. Being stuck in one low gear like this is called limp mode. It does this to protect itself when it sees an issue. If it is doing this, then there are codes that go along with it to tell us what the issue could be.

Please let me know if you have them. If you cannot get codes then most parts stores will pull them for free.