Transfer Case Motor/Computer/Speed Sensor

[rlhack]

I have a 98 XLT 4x4, 92K miles. At about 88K, the notorious 6 blinks of the "4WDHi/4WDLo" lights and this fourm led me to replace the speed sensor (actually the dealer agreed with my initial diagnosis). Now, the 6 blinks have returned. I returned to the dealer thinking the speed sensor has once again failed. The dealer has come back saying that there are two other problems: (1)the "computer" in the transfer case is no longer communicating and needs to be replaced and (2) the shift motor needs replacing. Admittedly the vehicle is road driven 95+% of the time and I do not ever move from the "auto" setting. Hence, I would guess that the shift motor is not an issue since it probably has only moved twice in year I have had it. I find the computer issue also wierd since something is smart enough and communicating to the extent that the lights are blinking 6 times.

In my opinion, the dealer is trying to scam some more money from me (quoted about $900 for two issues) when I still suspect the speed sensor. I know shift motors fail but seems unlikely for a vehicle that is road driven and the shift motor is never called into play. I thought the 6 blinks was definitely the speed sensor fault but maybe it is a more general transfer case fault.

Does anyone have any experience or input on this issue? Is there any issue with not addressing this issue immediately (long term damage to the transfer case); it would seem the worse situation would be that the vehicle will not shift to 4WD hi if and when called for.

Thanks loads. Hopefully I can save some money!!

 

[dreamr]

My 1st instinct would be to check the shift motor out if it won't let you shift to four low. Don't spend that much cash on one though. Just rebuild it. http://www.explorerforum.com/forums/showthread.php?t=123542&highlight=shift+motor+rebuild

It also may be true that the GEM needs reflashed or replaced. I suggest following up on the shift motor first though, and searching on here for how to test the GEM. I am currently searching for that very thread for myself, so I'll drop a link when I find it.

Edit** I should also add that the fact that you have only engaged your transfer case twice in a year could actually lead to problems with the shift motor, rather than preventing it's wear. Moving keeps it lubricated. Sitting makes it get stuck.

 

[rlhack]

Thanks.

Actually, when the speed sensor was replaced back at 88K miles, the shift motor appeared to work perfectly; 4WD Hi and 4WD Lo engaged just fine. However, as this is SoCal, not much need to move the selector out of "auto" , even with the rain we have been having.

My big mistake this time was not verifying the operation prior to taking the vehicle to the dealer for what I was sure was a speed sensor replacement (under warranty). I still find it very hard to believe that the shift motor would have any influence on this since I sincerely doubt that the GEM called upon the system for 4WD in the last few weeks.

At this point, based upon the claims that there is "no communications" between the GEM and what ever is being used to read it, I have to believe that the GEM has somehow failed (although this still does not explain the ability to produce the 6x blinking). Based upon a time crunch I have (want to take the vehicle on vacation next week) I had to bite the bullet and authorize replacement of the GEM (have also requested the old one back so I can have a spare and possibly reflash -- something that the dealer denies can be done). Seems like the most logical step.

Certainly looking for more information on the 6x blinking; is this a specific code or just and indication of a transfer case problem? Also, can someone enlighten me about the question of any possible damage if the vehicle is likely in the 2WD mode and cannot move to the 4WD mode? The trans is defintely not in 4WD hi or 4WD lo.

Thanks.

 

[TPLYNCH]

I think the dealer is hosing you big time. There really are no issues running with the lights flashing, unless the system error is causing the auto 4x4 to engage when it shouldn't. You'd know if it was by feeling/hearing it binding up. But if the GEM isn't communicating, then the system should be in failsafe mode - 2wd.

Have you had any other strange electrical problems since the lights started blinking? The GEM controls almost all electrical activity in the truck. If the GEM was bad, I would think it would lead to other issues. There was a recall on the GEM's several years ago. Did you have that recall done? If not, then the dealer should be charging you $0 for the GEM.

Oh, and the GEM can most certainly be reflashed. That was Fords fix for harsh engagement of auto starting with '95 models.