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97 GMC Sierra 4L60E proplem

slasher slasher
New User | Posts: 4 | Joined: 12/08
Posted: 12/18/08
10:02 PM

I have a 1997 gmc sierra Z71 with a problem I can't seem to figure out. After searching online for some time I've only come across the same problem 2 or 3 times, and those had no solution. Here's my problem:

Sometimes, after coming to a stop, the truck acts like it has a high stall converter. It will rev up higher than normal, then take off really hard. It may do it once a month, then work fine. It sometimes does it in reverse, too. The other day I was going to back into my yard, so I stopped on the street and when I put it in reverse, it revved higher than normal then engaged pretty hard.

I've had it work fine for months, then out of the blue it will happen. If I'm looking at having to replace the transmission, I have to decide if the truck is worth repairing.

I appreciate any help or advice.


slasher slasher
New User | Posts: 4 | Joined: 12/08
Posted: 01/06/09
05:59 PM


waynep712 waynep712
Enthusiast | Posts: 651 | Joined: 10/08
Posted: 01/06/09
06:46 PM

i would think that the use of a scan tool to examine the transmission codes that it will produce.. i don't know if non emission codes will turn on the check engine light...

but they will show with a scan tool....  

my thoughts and i am not a transmission expert are probably the modulated pressure control solenoid may be failing in some way...

it could also be a bad ground... loose connection in the wiring harness connector...  there are so many things that could go wrong..   that transmission is computer controlled...

and it takes a scan tool that views live data to see it.
there is an ATSG techtran manual available from automatic transmission parts vendors... for usually 20 bucks.. that will describe the system and some of its faults better... along with its fixes...

check the tsb titles over at   see if anything sounds like it may be your problem... most of those if you have the number and date can be printed at most car dealers..

and like other computer shifted transmissions.. there are tons of stuff that is not related to the transmission that will cause problems...    the throttle postion sensor..   the thermostat.. the accelerator position sensors on the gas pedal.. on some the neutral safety switch on the side of the transmission sends voltage signals to the transmission controller to let it know what gear its in.. those go intermitant..     dirty ground cables where they attach to the engine block are the cause of a ton of intermitant problems...  even if they look clean... clean them anyway... that is what the bests techs ***

pull codes before unhooking the battery please...  it may take weeks for a code to reset...  

slasher slasher
New User | Posts: 4 | Joined: 12/08
Posted: 01/08/09
02:53 PM

I scanned it and got codes P0141 (oxygen sensor) and code P1860. From what I understand, there are lots of things that can throw this code. I guess it's time to take it to the transmission shop Frown  

jgate-#002 jgate-#002
Guru | Posts: 953 | Joined: 06/07
Posted: 01/08/09
06:58 PM

Code 1860 breaks down to TCC PWM Solenoid Circuit, Electrical Problem, for the 4L60E trans  

waynep712 waynep712
Enthusiast | Posts: 651 | Joined: 10/08
Posted: 01/09/09
12:30 AM

what i thought it would be....

PWM stands for pulse width modulated pressure control solenoid..

there are trouble shooting charts for every code...

and that solenoid should be able to be changed without dropping anything but the pan and filter....

for more info google   DTC P1860... you will probably find a bunch of other people with the same problem..  and what it takes to fix it..  

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