Jump to content

4T65E 4th gear


ManicMechanic

Recommended Posts

Okay, yes this is my Aztek but since the Ws came with the same trans I am going to ask here, you can move it if you like.

 

I replaced the 4th clutch hub shaft, the clutch pack, thrust washers and all but it still will not go in to 4th. It acts like it wants to but goes back to 3rd. The TC locks up as it should, it seems. I don't have a Tech2 or anything like it to check to see if 4th is being commanded.

 

Kind of at a loss and not sure if it's mechanical or electrical.

Link to post
Share on other sites

Any experience with electronics? There's only two shift solenoids, that means if you wire a REALLY simple circuit to them involving a couple LEDs and a couple resistors you can compare them with the truth table to see what gear is being commanded. I have the truth table.

 

 

 

Shift Solenoid Patterns for each gear:

Range        1-2 Solenoid    2-3 Solenoid

Park           ON                    ON

Reverse     ON                    ON

Neutral       ON                    ON

1st Gear     ON                    ON

2nd Gear    OFF                  ON

3rd Gear     OFF                  OFF

4th Gear     ON                    OFF

Edited by Imp558
  • Like 2
Link to post
Share on other sites

I've seen some weird stuff with the valve body sticking and losing 4th, but always with other issues. Hate to say, I'm more of a fan of a full rebuild, though I know $h!t happens and sometimes you have to try

Link to post
Share on other sites

You may not have a tech 2, but can you at least scan for codes? OBD2 GM cars are really good about setting relevant transmission related DTCs. Even 1996 4T60e cars have good diagnostics. If it's commanding 4th and not getting it, it should set a P1870 code pretty quick. There may also be codes in the PCM for failed shift solenoids and any number of malfunctions with or without a P1870. Start by scanning it.

Link to post
Share on other sites

You may not have a tech 2, but can you at least scan for codes? OBD2 GM cars are really good about setting relevant transmission related DTCs. Even 1996 4T60e cars have good diagnostics. If it's commanding 4th and not getting it, it should set a P1870 code pretty quick. There may also be codes in the PCM for failed shift solenoids and any number of malfunctions with or without a P1870. Start by scanning it.

 

I do have a code reader, but no codes. I am not sure if it scans TCM codes or not.

 

I did put in new solenoids because I had a harsh shift in to drive and 1-2, with new solenoids that is gone.

 

Forgot to mention, I'm not terribly far from you, so if you want, I've got a core I could rebuild if you end up going that route. I know long down times stink. Good luck!

 

Raytown is quite a ways from Austin, Tx. hah (strangely enough, I have another friend in Raytown, Jacob Tuck, has a blue 1977 Chevy longbed truck in beautiful condition.) I do appreciate the offer!

Link to post
Share on other sites

Any experience with electronics? There's only two shift solenoids, that means if you wire a REALLY simple circuit to them involving a couple LEDs and a couple resistors you can compare them with the truth table to see what gear is being commanded. I have the truth table.

 

 

 

Shift Solenoid Patterns for each gear:

Range        1-2 Solenoid    2-3 Solenoid

Park           ON                    ON

Reverse     ON                    ON

Neutral       ON                    ON

1st Gear     ON                    ON

2nd Gear    OFF                  ON

3rd Gear     OFF                  OFF

4th Gear     ON                    OFF

 

I'm not too shabby with electronics so might have to give this one a try if I can.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...