Transmission help! 4t80e

[BodybyFisher]

11 hours ago, Dan03deville said:

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? 

I dont believe this is a manual valve problem.  I feel that you have a channel plate breech.  For instance, PRN (17) is located next to (32) reverse.  If think it is going to be something like a blown gasket between 2 fluid channels.  

I actually saw a blown gasket on my 96 when I replaced my input speed sensor, that while it didnt cause any driveability issues it was in fact blown out.  

I need to find my 4T80e shop manual to see the active fluid channels in NR, 

[Kingcadillac]

I have the same exact problem. I have the 2006 cadillac dts . 4t80e trans. For about two months now my cars been down and I've been driving myself insane tryin to figure out the problem I replaced both shift solenoids and the output shaft speed sensor. When both front wheels are in the air and I put the car in drive the wheels slowly spin but are not in sync with the throttle or engine. But when the car is not jacked. Up all tires on the ground no gears will engage reverse nuetral drive 3 2 1 nothin engages but it wants to. I have no check engine lights I run my obd reader on it dozens of times to watch live data. Theres a whining coming from the side case the flywheel is bolted to torque converter they both spin. I do have some pics though I could use help with an opinion on the pics. Shift cable is connected from hood to trans. But what I just noticed was the shift cable under the hood that spring does not compress and decompress. 

[BodybyFisher]

6 hours ago, Kingcadillac said:

I have the same exact problem. I have the 2006 cadillac dts . 4t80e trans. For about two months now my cars been down and I've been driving myself insane tryin to figure out the problem I replaced both shift solenoids and the output shaft speed sensor. When both front wheels are in the air and I put the car in drive the wheels slowly spin but are not in sync with the throttle or engine. But when the car is not jacked. Up all tires on the ground no gears will engage reverse nuetral drive 3 2 1 nothin engages but it wants to. I have no check engine lights I run my obd reader on it dozens of times to watch live data. Theres a whining coming from the side case the flywheel is bolted to torque converter they both spin. I do have some pics though I could use help with an opinion on the pics. Shift cable is connected from hood to trans. But what I just noticed was the shift cable under the hood that spring does not compress and decompress. 

Please explain what you mean by the highlighted statement.  HOOD to Trans?, explain  What spring?

The whining is a clue that something is not right with the pump or pressure

What did the transmission fluid look like when you dropped the pan?   Was there debris in the pan?  Is the filter in place?

When you changed the shift solenoids did you have a code for shift solenoids or did you just replace them?  What caused you to replace the shift solenoids?  Did you make sure all the CHECK BALLS were back in their correct locations?

When you changed the output shaft speed sensor, did you have a code for the speed sensor?, why did you replace it?

Pardon all the questions but we are coming in after all this work was done and need more info. 

[Kingcadillac]

The shif cable adjuster spring. Where its hooked to the top of trans on the side case. Yea I've been known that ig you can say I've juss been tryin everything else. And it is somethin with my pressure what's you're email so I can send you pics of my obd readings. Trans fluid was a bit dark and juss the normal amt of metals nothin excessive. I replaced both bottom scavenger filters but not the main filter. No codes for shift solenoids no trans codes at all . But lemme get you're email I'll send you all the screen shots. I replaced shift solenoids just to replace them. Yea check balls were in correct locations.  I replaced the oss sensor becsuse on my obd live data I'm getting a 0 reading for oss so I replaced it but the two wires that start at the connector of sensor and about a good 7 8 inches down both wires are open idk how so I taped them up but still no reading.  

[BodybyFisher]

Do me a favor, with the key off so no one gets hurt, have a friend put their foot on the brake on a level surface, and move the selector through the gears while you watch the PRD21 module that sits on top of the transmission.  See if the selector moves the manual valve in the transmission, thx

[Kingcadillac]

I'm currently not home. And I will I have the two lock pins that go in the cable adjuster out cuz I thought mayb hey I it just needs adjusted but now I'm tryin to get nuetral lined back up w nuetral and lock it back in. But if I remeber correctly I wanna say it does move it cuz when I had the bottom pan off I did that went through the gears and its movin in the bottom of the trans pan. I have alot of obd screenshots I could use s second opinion on though i juss cant figure out how to post them on here

[BodybyFisher]

How did you handle the check balls when you changed the shift solenoids

Why did you change the shift solenoids?

Why did you change the vehicle speed sensor on the output shaft?

I have seen problems like this before when someone changes the shift solenoids, but PLEASE, why did you change the shift solenoids

Please answer the above questions

[Kingcadillac]

Didnt drop one check ball the whole time nor even took them out of there right spots. I changed them for shits n giggles.  I changed the oss sensor because my live data on my obd was reading 0 for the oss while the iss was gettin a reading.  I think I need to trace both wires from sensor. I changed them juss to change them.  And the problem started before I changed them not after. I juss got the pan back up the other day for the second time dropping it and gettin all the old fluid out. 

[BodybyFisher]

Ok good, you read my mind, I wasn't sure if this began before or after the shift solenoid problem.   

If the vehicle speed sensor (vss) is bad, your speedometer will be non functional.

If the ISS speed sensor is bad, it will rely upon the vss, but not well.

Any P codes that are set?  Can your analyzer confirm what gear the selector is in?

You sound like an advanced mechanic.  You may need to attach a pressure gage to see what is going on.

How did it fail, suddenly?, slipping?, how bad is the whine?  Did you check the filter and pan for clutch debris? Did the fluid smell burned?

[Kingcadillac]

No the sensor wasnt bad but I still replaced it and still getting a 0 reading on the obd live data. Which makes me believe the open wires have somethin to do with it that I taped up. Or torque converter or tcc solenoid because the torque converter has somethin to do with the output . If I could post these screenshots i have than itd make sense . My TAP system is all messed up on the obd live data all my pressure taps read high up in the 90 psi range that's just idling. And I've never heard of this before but my engine torque on live data reads negative . May be the pressure control solenoid the tcc solenoid, something on the pump broke, clogged main filter, or torque converter itself . And when it officially happened for a while my car would shift perfectly fine from 1 to second no probs there but than 2 to 3 was more of a hard shift but it was only 2-3. And the fluid was dark and did smell a lil burnt. But no excessive metals in the pan.  Normal amt on magnet. But yea while I was drivin home from work one morning it juss up n quit workin. 

[Kingcadillac]

[BodybyFisher]

12 minutes ago, Kingcadillac said:

No the sensor wasnt bad but I still replaced it and still getting a 0 reading on the obd live data. Which makes me believe the open wires have somethin to do with it that I taped up. Or torque converter or tcc solenoid because the torque converter has somethin to do with the output . If I could post these screenshots i have than itd make sense . My TAP system is all messed up on the obd live data all my pressure taps read high up in the 90 psi range that's just idling. And I've never heard of this before but my engine torque on live data reads negative . May be the pressure control solenoid the tcc solenoid, something on the pump broke, clogged main filter, or torque converter itself . And when it officially happened for a while my car would shift perfectly fine from 1 to second no probs there but than 2 to 3 was more of a hard shift but it was only 2-3. And the fluid was dark and did smell a lil burnt. But no excessive metals in the pan.  Normal amt on magnet. But yea while I was drivin home from work one morning it juss up n quit workin. 

THIS POST CAME AT THE SAME TIME AS YOUR PRESSURES ABOVE.  

The VSS only produces a signal when the vehicle is moving, it monitors axle speed.

I am going to post this LOSS of DRIVE trouble chart.  As you can see it can be the torque converter, pump, and mechanical issues, none of which are good.   I would borrow a gage and connect it up.  If you need the tap location, Ill scan the service manual.   Do you have the service manual?

[BodybyFisher]

What analyzer are you using?   Those pressures were pulled during gear changes?, prior to it failing?, how are you getting those pressures if you have no drive?  thx

I am going to check the manual for symptoms of a rough 2-3 shift, and check what normal pressures should be.

Are you getting 93 psi in park?

[Kingcadillac]

Tap location? Is that where I would put the pressure gauge? And no those are the pressures I got after it malfunctioned. I need any kind of manual help I can get. Autel obd. Idk how I'm gettin those pressures like I said when both front wheels are jacked up off the ground and I go through all my gears the wheels spin but slowly and not in sync with the throttle.  Very weak engagement. And shouldn't the oss be gettin a reading no matter moving or not ? If you get a input reading you have to get a output reading or so I thought with the 06 dts 4t80e.  

[Kingcadillac]

I honestly think its gonna be the turbine shaft or the pump shaft.  

[BodybyFisher]

1 hour ago, Kingcadillac said:

Tap location? Is that where I would put the pressure gauge? And no those are the pressures I got after it malfunctioned. I need any kind of manual help I can get. Autel obd. Idk how I'm gettin those pressures like I said when both front wheels are jacked up off the ground and I go through all my gears the wheels spin but slowly and not in sync with the throttle.  Very weak engagement. And shouldn't the oss be gettin a reading no matter moving or not ? If you get a input reading you have to get a output reading or so I thought with the 06 dts 4t80e.  

The speed sensor on top of the output shaft is called the VSS or vehicle speed sensor, it provides a signal for the speedometer and is a backup for the input speed sensor ISS if it malfunctions.  The VSS measures the axle rotation.   

Now I understand, with it on a lift, it goes through the gears with no force behind it, that is actually good news, in a odd way.  That is why you said, it is TRYING to engage, it must be slipping very badly.  

If it was a pump shaft, you probably wouldn't be getting pressure, just a guess.  

Again, have you pulled all P codes?   

Can you get the pressure in NEUTRAL and PARK?, it looks like you are getting pressures through out the gears. 

I have a ATRA 4T80E manual, let me look through it, I hope I can find it.  

I want to research your pressures, the rough 2-3 shift, whine

[Kingcadillac]

Again no p codes

[BodybyFisher]

2 hours ago, Kingcadillac said:

Tap location? Is that where I would put the pressure gauge? And no those are the pressures I got after it malfunctioned. I need any kind of manual help I can get. Autel obd. Idk how I'm gettin those pressures like I said when both front wheels are jacked up off the ground and I go through all my gears the wheels spin but slowly and not in sync with the throttle.  Very weak engagement. And shouldn't the oss be gettin a reading no matter moving or not ? If you get a input reading you have to get a output reading or so I thought with the 06 dts 4t80e.  

Here is the pressure gage tap location, you need special tool J21867-94 it looks like, but there may be a way around that.  Your pressures seem high in the 90s based on the manual

 

[BodybyFisher]

Maybe those pressures aren't too bad, look at this list of pressures 

[Kingcadillac]

How do I do this exactly... can you send me pic of that next page also

[Kingcadillac]

But why are they red you know? Shits got me so mind smurfed lol 

Edited January 22, 2020 by Kingcadillac

[Kingcadillac]

Not next page just the next column

[Kingcadillac]

On 3/16/2019 at 12:08 AM, BodybyFisher said:

I dont believe this is a manual valve problem.  I feel that you have a channel plate breech.  For instance, PRN (17) is located next to (32) reverse.  If think it is going to be something like a blown gasket between 2 fluid channels.  

I actually saw a blown gasket on my 96 when I replaced my input speed sensor, that while it didnt cause any driveability issues it was in fact blown out.  

I need to find my 4T80e shop manual to see the active fluid channels in NR, 

A blown gasket will make the trans lose pressure and not wanna engage like that? I did replace the lower valve body gasket or spacer whatever it's called so I wonder which one it could be

[Kingcadillac]

I really wish I had that manual

[BodybyFisher]

4 hours ago, Kingcadillac said:

I really wish I had that manual

You can find the service manuals on ebay and amazon.  Here is the other column.

Any type of pressure loss or gasket blow out will cause problems.  

I just spent the day looking for my ATRA manual with no luck.  Ill keep looking