95 XLT Control Trak 6 flashes of 4WD/4LO

[95-XLT-VT]

I've got a 95 XLT with control trac, about 110k miles. When I turn the selector knob to Auto 4WD, or 4 LO, both dash lights flash 6 times after about 3 minutes of driving, if I leave it in auto 4, it flashes again a few minutes later. It never flashes if I leave it in 2wd. If I set the switch to 4 LO, I can hear the case shift into 4lo, and out when I switch to either auto or 2wd. This means the shift motor is OK - right?

Here's what I've tried so far:
Unhooked battery for every attempt
Fluid change - No effect
Front and rear hall sensors replaced - No Effect
Unhooked and re-connected motor connector on transfer case - No Effect
Removed and re-installed GCM - No Effect

There is supposed to be a connection under the drivers seat - didn't have time to dig it out yet. Any other suggestions on what else I could check??? Thanks in advance.

 

[95-XLT-VT]

OK, here's the funny part. To see if it actually was failing I took it for a drive, put it in 4WD and drove until the lights flashed, found a dirt road, and stopped. In 4 auto, I put it in first, turned the wheel, and floored it. Sure enough, three spin marks. So I try it again in 4 Lo. Three marks again. Looks to me like it's 'fixed'. Especially since it's my winter beater, and I grew up with old 4wd trucks and use 4wd when its needed.

 

[rmmiller2050]

it is most liley th e shift motor position resolver not registering where the shift motor is -rotationwise. this happens due to the very common "deteriorated travel limit bumper". See other threads on shift motor repair. Your GEM and shift controlmodule are both operating as they sahoul dgiven what you describe, yer shift motor is good, your shift fork inside the tcase is prolly good(else it would slip out of 2hi when you slacked off the gas) ,your hall sensors are good(else it wouldnt have gotten yer three skid marks) in 4hi , your tcase electric clutch is working else no front axle engagement would take place. You Torkondemand (TOD) relay is working and most likely yer tcase clutch solenoid is working all the time too. There are two addditional solenoids , Lo2Hi and Hi2Lo that reverse the polarity to the shift motor (to get it to reverse its rotation and thus shift from hi range to lo range. all that crap seems to be working .) I understand that the 6 flashes is the little GEM module's brain telling you that it is either drunk , on crack or just confused . Generally this means that given all the other speed sensing inputs and transmission selector inputs it cant make sense of the signals it is receiving from the "over-travelled" shift motor resolver (essentially thers is a contctor that is not making contact and sending correctly). I understand that it does not take much rotation past the stop point to cause this phenomenon. The quick thing to try is to get the resolver (the blue thingy) attached to the outboard side of the shift motor gearbox loosened (you willl likely need anti-tamper TORX head bits)and (after you disconnect the neg batt term) and rotate teh blue thingy CCW a very little bit- 1/8 inch or so , hook up batt and test drive; keep repeating this for as much rotation as the slotted screw holes allow. If this dont fix it then tear the shift motor apart as in the shift motor rebuild threads or just go git a new one for about 75-100 zslotnyz.