1999 Trooper TOD

I've had some troubles with my 99 trooper TOD. The electrically operated vacuum valves on the center of the front axle have failed twice - once, 2 years ago while they were still under warranty and again, just recently. The factory district manager said it is "rare" for them to fail, but I got the ones they took off this time and they were pretty corroded. I haven't taken them apart, but though they work "electrically", they don't open/close the vacuum properly. So I guess they are corroded inside as well.

While the TOD was not working, in my attempts to get it to work, the red check light came on. The owners manual doesn't say any detail about this light, but it says to stop the vehicle, turn the engine off, wait (I forget how many seconds/minutes) and restart. If the light hasn't gone out, it should be taken to the dealer. So it doesn't really say what the light means. However, in another section, it warns to not push the TOD button while the wheels are slipping/spinning. You can engage the TOD while driving, but just not while a wheel is spinning. I think that must throw the computer off. Since I had mine repaired, the red check light came on once, and I think it was when I pushed the TOD switch while a wheel was slipping. So I suspect that the red light must be from the TOD computer and must indicate that something didn't operate in proper sequence. A spinning wheel probably throws the sensing off because it then thinks when the wheel stops spinning, that something is wrong.

I wish I knew more about this system, but I don't. But I'd be somewhat careful about "when" I turned on the TOD system so that it sensed everything working together (all wheels turning at the same speed upon engagement or all stopped). BTW, when my vacuum valves failed, the TOD did operate erratically for a day or so before it quit working entirely and the "AUTO" light would then just flash constantly - just like it does if you press the TOD switch while standing still - you have to move the vehicle forward (or backward, I guess) to get the wheel locks to engage before the auto light will stay on steady.

That's all I can contribute, which isn't much.

Chuck

If you want to email me, my id is galbaccr and my ISP is earthlink dot net. ie., snipped-for-privacy@myisp.net

Hmmm...so how are you supposed to engage 4wd when you're truly stuck? :-)

"Ntelos" wrote in message news:lXz_b.17018$ snipped-for-privacy@fe01.usenetserver.com... | Hmmm...so how are you supposed to engage 4wd when you're truly stuck? :-) |

Well, except when my vacuum switch wasn't working - which seemed to completely disable the 4WD - I've been able to put the thing in neutral in my driveway, shove the low range lever forward, and you can feel the front grab right away and start pulling as soon as you go into Drive. I've pulled my trooper out of my driveway, over the danged pile of frozen slush the snowplow driver insists on leaving for me, and onto the road several times this way. You have to get it back out of low range right away on dry pavement. You can feel the front tires really scrubbing and stiff turning on the dry pavement so I try not to go more than a few feet before I stop and get it out of low range. BTW, this works no matter whether you have the TOD switch in (on) or out (off). That low range is pure 4WD. I haven't been totally stuck, but I've noticed when I punch in the TOD switch while standing still, the lights flash on and off slowly (same as when it isn't working), until I move the car. It doesn't seem to take much - just a few inches and the green light goes on steady. But this doesn't happen with the low range (assuming the vacuum switch is working). All of the lights come on instantly. You can actually feel the front end lurch forward as soon as you put the thing from neutral to drive. To get the thing out of low range, you must stop and put the transmission in neutral, once again. So, when you can use it, the TOD is much more convenient. And probably much easier on your tires.

Chuck

OK, makes sense... I've used the 4L on it a few times when I wanted 4wd to be readily available... had it out on the beach on the Outer Banks of NC and quickly realized TOD wasn't going to cut it - it was kicking in almost too late, so I went to 4L and it was fine. Good to know it locks in really quickly when you need it (distance-wise).

Thanks,

Wesley