Leo78
New Member
- Joined
- April 17, 2015
- Messages
- 3
- Reaction score
- 0
- City, State
- Colorado
- Year, Model & Trim Level
- 1997 Ford Explorer XLT
So, ive looked through so many threads on so many sites my eyes are bleeding and have some things narrowed down... but no REAL answer. Hopefully a Master Tech out there can offer some insight.
So my issue is a recurring one with the 4wd system not functioning correctly. i dislike this model's "auto" feature altogether but whatever.
2 years ago i tore down the vehicle to replace the notorious timing chain cassette, and replaced the trans which was blown (along with the dtr, and a TC speed sensor) and some other minor funstuff at the same time.
So back then, when i put it all back together. the 4wd was still acting funny. the "auto" as i recall was doing the same as it is now, which is engaging 4high when it should not be. however, i never had problems with 4low engaging despite that. anyway, because i didnt feel like fOrK'ing with it, and lack of money... i just unplugged the TC since i dont use 4wd much anyway.
Recently (within a month) i plugged the TC in to play on state land, and the system was engaging and disengaging as it is supposed to... no problems. probably for a couple weeks drove fine.
Then my wifes truck was in the shop (ironically for something similar) so she had to use my vehicle. i get a text saying my explorer has the 4wd and 4low lights flashing at her. so she brings it home, and the lights are no longer flashing, but i can tell it is defenetely in 4High.
So, skipping all the screwing around with it that i did after that, Heres the full description of what its doing/not doing now:
1. Turn on vehicle, selector set to "auto" (dont even have to start, just key forward to ACC) and 4High engages. No dash indicator lights up in doing so, and listening, you can hear the gem module clicking a bunch, and usually the clunk from the engagement. Sometimes it engages, disengages, then engages again.
2. i also had a few times where there was grinding and free spinning, but i did figure out this was on the couple occasions when i started the truck and quickly put it in gear (D or Reverse) to move... because when you start the vehicle the TC starts in a neutral state and then after a few gem clicks, clunks into what is obviously 4high, starting it up and throwing it into gear before it has engaged results in a miss until it either spins down, or i change gear (D, N, or R, depending)
3. While the 4wd light does come on when you switch from "auto" to 4high regardless of whether its physically in 4high.... the 4Low does not /will not engage at all. No dash light, nothing. Switching from 4 high to 4low turns the 4wd light off, but no effect otherwise.
With the TC unplugged, the problem goes away, which i assume should rule out most if not all direct TC problems including speed sensors, shift motor, electromagnet clutch, ect. Though most of those problems could still be the culprit behind the 4low not engaging. the 4wd/4low lights do the 6 flash bit... but im assuming they should, with the TC unplugged.
The fact that it is actively engaging/disengaging the on demand 4high, while in "auto" mode, leads me to belive that fuses and relays are probably not the issue here. (ive checked fuses, but not relays)
So my best guess is that the GEM is a total P.O.S.
I know some versions of this control trac system are slightly different, in what exactly was controlled by what module.... im not sure if mine is controlled entirely by the GEM, or if it ALSO has a shift control module on top of the shift control relay.
So im hoping one of you professionals has a solid way to un-confuse me on this, and possibly provide some insight on how to diagnose the GEM/TCCM or whatever other module might be the P.I.T.A. here... because though logic tells me the GEM seems likely... logic also tells me that if the GEM was bad, id probably have other stupid things going on like windows, lights, locks or other accessories not working as well....
1997 explorer XLT, SohC 4.0, automatic
So my issue is a recurring one with the 4wd system not functioning correctly. i dislike this model's "auto" feature altogether but whatever.
2 years ago i tore down the vehicle to replace the notorious timing chain cassette, and replaced the trans which was blown (along with the dtr, and a TC speed sensor) and some other minor funstuff at the same time.
So back then, when i put it all back together. the 4wd was still acting funny. the "auto" as i recall was doing the same as it is now, which is engaging 4high when it should not be. however, i never had problems with 4low engaging despite that. anyway, because i didnt feel like fOrK'ing with it, and lack of money... i just unplugged the TC since i dont use 4wd much anyway.
Recently (within a month) i plugged the TC in to play on state land, and the system was engaging and disengaging as it is supposed to... no problems. probably for a couple weeks drove fine.
Then my wifes truck was in the shop (ironically for something similar) so she had to use my vehicle. i get a text saying my explorer has the 4wd and 4low lights flashing at her. so she brings it home, and the lights are no longer flashing, but i can tell it is defenetely in 4High.
So, skipping all the screwing around with it that i did after that, Heres the full description of what its doing/not doing now:
1. Turn on vehicle, selector set to "auto" (dont even have to start, just key forward to ACC) and 4High engages. No dash indicator lights up in doing so, and listening, you can hear the gem module clicking a bunch, and usually the clunk from the engagement. Sometimes it engages, disengages, then engages again.
2. i also had a few times where there was grinding and free spinning, but i did figure out this was on the couple occasions when i started the truck and quickly put it in gear (D or Reverse) to move... because when you start the vehicle the TC starts in a neutral state and then after a few gem clicks, clunks into what is obviously 4high, starting it up and throwing it into gear before it has engaged results in a miss until it either spins down, or i change gear (D, N, or R, depending)
3. While the 4wd light does come on when you switch from "auto" to 4high regardless of whether its physically in 4high.... the 4Low does not /will not engage at all. No dash light, nothing. Switching from 4 high to 4low turns the 4wd light off, but no effect otherwise.
With the TC unplugged, the problem goes away, which i assume should rule out most if not all direct TC problems including speed sensors, shift motor, electromagnet clutch, ect. Though most of those problems could still be the culprit behind the 4low not engaging. the 4wd/4low lights do the 6 flash bit... but im assuming they should, with the TC unplugged.
The fact that it is actively engaging/disengaging the on demand 4high, while in "auto" mode, leads me to belive that fuses and relays are probably not the issue here. (ive checked fuses, but not relays)
So my best guess is that the GEM is a total P.O.S.
I know some versions of this control trac system are slightly different, in what exactly was controlled by what module.... im not sure if mine is controlled entirely by the GEM, or if it ALSO has a shift control module on top of the shift control relay.
So im hoping one of you professionals has a solid way to un-confuse me on this, and possibly provide some insight on how to diagnose the GEM/TCCM or whatever other module might be the P.I.T.A. here... because though logic tells me the GEM seems likely... logic also tells me that if the GEM was bad, id probably have other stupid things going on like windows, lights, locks or other accessories not working as well....
1997 explorer XLT, SohC 4.0, automatic