Transmission help! 4t80e

[Eyik66]

My car won't go into gear at all. The fluid was low, so I added some but still no gears. Put the car in the air, and the tires want to spin forward in drive, park, and reverse. No transmission codes on the dic. Pressure control selonoid ? Time to replace the transmission?

[Bruce Nunnally]

Welcome to CaddyInfo!

Can you determine if the car thinks it is getting into gear? What year/model is it?

[Eyik66]

The gear selector moves through the gears on the dic

[Bruce Nunnally]

The electronic connector going into the transmission is a large pigtail type connector. Might be a waste of time, but perhaps disconnecting it and reconnecting it -- with the engine off and the battery disconnected -- would ensure the issue is not just a miscommunication issue.

[Eyik66]

Ok will do. It's a 2001 deville. Any ideas why it's moving the wheels forward in all gears (even reverse). Seems like it could be a pressure issue

[BodybyFisher]

Any buzzing or hydraulic noise? What does the fluid smell like? How much fluid did you need to add?

Explain no codes on the DIC?, did you extract the codes using the on board diagnostic system? They won't come up on their own

[Eyik66]

Yeah I used the dic to read the codes. The fluid is still red with a good smell, my buddy actually added the fluid so let me check. Can you describe the noises I should check for? I'll give it a good listen

[KHE]

Your initial problem description is confusing. Are you stating that no matter what position the gear selector is in, the car wants to move forward?

[BodybyFisher]

The noise is sort of the noise a power steering unit makes when it low in fluid, a whining

WHen the car was in the air the wheels moved?

Do you feel an initial engagement when you move from N to DRIVE OR REV, sort of a bump?

Does it feel like its slipping?

[Eyik66]

Your initial problem description is confusing. Are you stating that no matter what position the gear selector is in, the car wants to move forward?

thats exactly what is happening. It won't move when the car is on the ground so it must be slipping, but when its in the air, the front wheels are clearly spinning forward no matter what the shift selector is on. Park/reverse/drive all moved the wheels forward.

As far as feeling a bump when I first shifted, I want so say that I did feel a bump on the first shift, but I'll have to go try again to be sure.

Edited June 22, 2012 by Eyik66

[KHE]

It sounds like the shifter cable is misadjusted but that would set a trouble code. I would need to study the shop manual to see what is going on but off hand, if the shift solenoids are stuck in 1st gear, that might cause the problem but again, that would set a code and shift solenoids are not usually an issue on the 2000+ cars.

[Eyik66]

I'm going to put it back in the air and post a video on youtube. I'll post the link a little later

[Eyik66]

for some reason they locked in park this time, but kept just spinning forward in all gears:

[sts03]

Maybe a broken axle

[Cadillac Jim]

The only no-code cause that I can think of is bad transmission wiring connections. I believe Park includes a mechanical connection to the locking pawl (probably through a cable; others may chip in to correct me on this) but everything else is an electrical connection to the PCM. Look at the big connector under the car from the wiring harness to the transmission, and the wires to the transmission and back to the wiring harness.

[Dan03deville]

I am having the same problem with my 03 Cadillac deville. Did you find it the problem? 

[Cadillac Jim]

Do you have any OBD codes?  Run the codes and post them here.

[Dan03deville]

I got 3 codes but not for transmission. I got evap leak, idle high, idle low codes. Nothing on my scanner for a transmission code

[Dan03deville]

My column shift goes to park. In reverse, drive and nuetral the wheels go forward. 

[Cadillac Jim]

Is this with the front wheels off the ground and engine at idle?  When the wheels are on the ground and you give it a bit of throttle in Reverse, does the car move forward?   Does the car surge against the Park pawl when you give it a bit of throttle in Park?

This is the FSM entry for "Forward motion in N:

Checks	Causes
DEFINITION: Forward Motion in Neutral
Forward Clutch Housing	Feed hole plugged, inspect tower
Forward Clutch Piston	Jammed
Forward Clutch Plates	Seized or jammed
Forward Clutch Springs	Jammed
Forward/Coast Clutch Support Hub	Holes plugged
Manual Valve	Mispositioned or stuck
Shift Linkage	•  Mispositioned     •  Disconnected

The only do-it-in-the-driveway DIY check that is listed is to check the shift linkage.  The FSM drawing of the cable attachment to the transmission:

1 - where the cable attaches to the transmission.  This may be disconnected in your case.

2 - cable holder, with adjustment.  The FSM adjustment process follows.

Range Selector Lever Cable Adjustment

Notice: Adjust the shift control cable only while the transaxle and the gear selector are in NEUTRAL. Failure to do so may cause mis-adjustment.

 

1. Set the parking brake and chock the wheels.
2. Remove the shift cable terminal from the transmission manual shaft lever pin.
3. Pry on the shift cable terminal at the manual shaft lever pin with an appropriate tool. Prying or pulling up on any other part of the shift cable may result in damage to the shift cable .


4. Fully lift the adjuster lock button. Ensure that the adjuster is free to move.
5. Place the transmission manual shaft lever in (N) Neutral. In order to find (N) Neutral, rotate the lever fully counterclockwise to (P) Park, and then clockwise 2 clicks into (N) Neutral.
6. Place the gear shifter inside the car to the (N) Neutral position. Use the transmission shift indicator on the console to find (N) Neutral.
7. From under the hood, grasp the shift cable terminal and pull it toward the pin on the manual shaft lever. The shift cable adjuster spring should compress as the terminal is moved toward the pin.
8. Attach the pin to the lever by pushing down carefully until it snaps.

Do not pull the terminal beyond the pin and then push back. This action could move the shifter out of (N) Neutral.

1. Press the adjuster lock button down flush with the adjuster body.
2. Shift to (P) Park and release the parking brake while applying the service brake.
3. Start the engine and assure all of the indicated gear positions match the vehicle response.

[Dan03deville]

I have discovered the shift valve and shifted the car by hand on the transmission and it still drives in all gears except park. Could this be the forward clutch being stuck? How can I check or fix this? 

[Cadillac Jim]

21 hours ago, Dan03deville said:

I have discovered the shift valve and shifted the car by hand on the transmission and it still drives in all gears except park. Could this be the forward clutch being stuck? How can I check or fix this? 

Does the shift lever drive the shift valve in the proper position as shown in the shift indicator?  The two missing pictures labeled Object Number 97542/97544 are below:

Checking the other parts requires removal and disassembly of the transmission.  If the external adjustments, fresh Dexron VI, etc. don't work for you then I would suggest that you commit to a transmission exchange or overhaul.  If you do internal automatic transmission work yourself, perhaps someone else can step up here.  I do suggest that you be prepared for clean, well lighted indoor workspace with a complete factory overhaul manual for the 4T80E before you start.

[Dan03deville]

Ok. Thank you. I appreciate you taking the time to help. I will update the post once I figure out what the problem was, to help others that may find themselves in this situation. 

[BodybyFisher]

Are you saying that in neutral, it acts like it is in drive?

What does it do in reverse?

[Dan03deville]

Yes in neutral and reverse it acts like it's in drive. I replaced the lower valve body, internal mode switch, shift solenoid 1 and 2. Any other ideas?