4l60e no 4th tcc or auto shifting
01-10-2012, 06:01 PM
#1
Teching In
Thread Starter
Join Date: Dec 2011
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
4l60e no 4th tcc or auto shifting 95 tahoe rebuilt trans has transgo hd2 raybestos z pack and corvette servo. for some reason it wont shift automatically has no 4th or tcc apply. this is driving me carzy. can someone please help? id even be willing to pay
01-10-2012, 07:47 PM
#2
Moderator
More info would help.
* In particular did these problems occur on day 1 after the rebuild, or not until later? If later, did they all occur suddenly or gradually.
* Was the PCM tuned?
* When you say "wont shift automatically", do you mean even from 1st to 2nd to 3rd?
* Is the car starting in 1st gear, or is it starting and staying in 3rd gear, which would indicate "limp mode"?
I would start by making sure the electrical connector for the trans is fully seated.
* In particular did these problems occur on day 1 after the rebuild, or not until later? If later, did they all occur suddenly or gradually.
* Was the PCM tuned?
* When you say "wont shift automatically", do you mean even from 1st to 2nd to 3rd?
* Is the car starting in 1st gear, or is it starting and staying in 3rd gear, which would indicate "limp mode"?
I would start by making sure the electrical connector for the trans is fully seated.
01-11-2012, 10:39 AM
#3
Teching In
Thread Starter
Join Date: Dec 2011
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
yea its done it since day one. no tuning trucks stock. and it does start in 3rd gear and i have to go down to 1st and go up from there. it does nothing when the lever is put in od. i also put a jumper on the dtc port and just get code 12 which is no codes.
01-11-2012, 04:40 PM
#4
Moderator
Starting in 3rd gear means you are in "limp mode". This could be caused by:
* Electrical connector to trans is not plugged in
* Solenoids not plugged into internal harness
* Shift solenoids are bad
* Other things too, but check the above ones first
I suspect a stock trans in limp mode will stay in 3rd gear no matter what gear (D-3-2-1) you have selected (but I don't know that for sure). However, the HD shiftkit includes a valve body mod that will force 1st or 2nd gear if manually selected. That is why you can manually shift the car from 1st to 2nd to 3rd. (This non-stock ability would confuse some mechanics.)
First check that the electrical trans cable is plugged in.
HP Tuners or a high-end scanner will let you select a gear; with the ignition on, engine off in a quiet garage, you can hear the solenoids click.
If there is no click, or you want to skip that step, drop the pan and check the electrical connections to the solenoids. If OK, disconnect them and check that they have a 10-20 ohm resistance. They only cost about $15 each to replace.
And/or - turn on the ignition and check that there is close to 12V on the solenoid connections.
There are some recent/current threads on "4L80 limp mode"; most of the suggestions in those apply to you too. There are some very specific testing procedures listed in those.
BTW - Before dropping the pan, I prefer to use a cheap $10 "liquid pump" to pump out as much transmission fluid through the dipstick as possible. Else dropping the pan can make a big splash.
Alternatively, I'm confident a trans shop could quickly figure out the problem. Seems unlikely there is a serious problem with the trans. Good luck.
* Electrical connector to trans is not plugged in
* Solenoids not plugged into internal harness
* Shift solenoids are bad
* Other things too, but check the above ones first
I suspect a stock trans in limp mode will stay in 3rd gear no matter what gear (D-3-2-1) you have selected (but I don't know that for sure). However, the HD shiftkit includes a valve body mod that will force 1st or 2nd gear if manually selected. That is why you can manually shift the car from 1st to 2nd to 3rd. (This non-stock ability would confuse some mechanics.)
First check that the electrical trans cable is plugged in.
HP Tuners or a high-end scanner will let you select a gear; with the ignition on, engine off in a quiet garage, you can hear the solenoids click.
If there is no click, or you want to skip that step, drop the pan and check the electrical connections to the solenoids. If OK, disconnect them and check that they have a 10-20 ohm resistance. They only cost about $15 each to replace.
And/or - turn on the ignition and check that there is close to 12V on the solenoid connections.
There are some recent/current threads on "4L80 limp mode"; most of the suggestions in those apply to you too. There are some very specific testing procedures listed in those.
BTW - Before dropping the pan, I prefer to use a cheap $10 "liquid pump" to pump out as much transmission fluid through the dipstick as possible. Else dropping the pan can make a big splash.
Alternatively, I'm confident a trans shop could quickly figure out the problem. Seems unlikely there is a serious problem with the trans. Good luck.
