Back in his car to drive through gate, the car wouldn’t engage in drive

Hi,

Is the check engine light staying on while the engine is running? There could be diagnostic trouble codes to help explain what is happening. If it isn't and there was no evidence of a problem such as slipping or slow to engage issues, I suspect something has lowered line pressure in the transmission.

This guide can help

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

Again, this recommendation is based on the idea that no trouble codes are present. At this point, I would remove the transmission pan and inspect both the filter to see if it is plugged and the pan for evidence of clutch material or even metal shavings. If the fluid hasn't been serviced in a long time, it may have caused something to plug.

Before you do that, check and confirm that the shift indicator in the vehicle is working and indicating the correct selected gear. Also, make sure the linkage to the shift lever on the transmission is actually moving and not loose or disconnected. If I recall, the shift linkage is actually a cable, so check that as well.

Let me know what you find.

Joe

I am not sure about the check engine light being on or not, but I do know that he says it will engage in reverse with no problems whatsoever, and the fluid is clean, and smells normal. There was no problems with slipping or slow to engage shifts prior to this problem.

Check to see if the shift indicator indicates you are in drive. The vehicle has what is called a range sensor. It is what determines what gear the transmission goes into. If it is bad, it can be causing issues.

Check that and let me know what you find. Also, let me know if the linkage was checked. There could be an issue with the shift cable.

Let me know.
Joe

Yes, the shift indicator does indicate it being in drive, and any other gear we put it in as well. He said he checked the linkage and it appears to be just fine as well. He also said that it Still moves in 1st gear as well as reverse, but not in any other gear.

Hi,
Interesting. The idea that first and reverse makes sense because they work off the same clutch pack. At this point, you really need to have the computer scanned to determine codes and if any are related to the transmission. The idea that it shifts into drive and reverse leads me to believe it isn't a pressure issue but rather an electronic issue.

Do you have access to a scanner which can read transmission codes?

Joe

Not right away, do you need a special scanner to read transmission codes? A regular obd code reader won’t do read them?

It really matters what kind of scanner you have. Most of the lower price ones are only for engine codes and won't read others. There are codes for multiple different components. Even the HVAC will provide codes. Things are getting more and more complex every day.

Let me know if I can help.

Joe

Will do, thank you! My husband is superposed to be borrowing a really nice snap on scanner (super expensive!) From a friend today so we can check the codes.

Happy to help. Let me know what you find as far as codes.

Take care,
Joe

Update: We borrowed a code reader, a really nice Snap On one, and it didn’t pick up anything. Then, when my dad was messing around with it, he unplugged a piece on the top of the transmission, and the transmission engages in all the gears. When he plugged it back in same problem as before. Picture is of piece he unplugged. The piece with the wires coming from it.

I see the range sensor. The connection near it is for the transmission control circuits. I think that is what was unplugged. Take a look at the pic below. Are those the color wires which you are seeing in the harness? I can't tell from the pic. If they are, my first suspect is a problem with the EPC solenoid on the valve body. EPC stands for electronic pressure control. It may be stuck closed when power is applied.

Let me know.

Joe

Okay, this sounds like we are heading in the right direction. He says he is only getting any noise from one of the shifter solenoids when he is shifting gears, and it’s in D1. He’s not getting anything from the other solenoids. How would one go about testing your theory?

The diagnostics for testing the EPC is listed in the attached pictures. This is somewhat involved. If you run into trouble or have questions, please feel free to let me know and I'll try my best to help from here.

Let me know what you find.

Joe

So it doesn’t appear to be the solenoids. Can you think of anything else that could be cause if this problem? My father is about to give up the goat on this project, he is at road block here, he doesn't have enough knowledge to go any farther on this one.

So it doesn’t appear to be the solenoids, can u think of anything else that could be cause if this problem? My father is about to give up the goat on this project, he is at road block here, he doesnt have enough knowledge to go any farther on this one

The only other thing I can say to check is if transmission line pressure is within spec. There could be an issue with the epc, electronic pressure control solenoid

If you look at pic 1, it shows where to connect on the trans to check pressure. Pic 2 shows the values / pressure specifications.

Do this and lets see if there is any pressure.

Joe

Update: he has now taken the transmission completely out of the car and taken it all apart and there is no problems with the transmission itself. So why is it not working still? We were thinking maybe in the valve body?

Did you check line pressure prior to removal? Low pressure will cause issues. As far as the valve body, there really isn't a lot to go wrong there unless dirt was an issue.

Let me know.
Joe