lschafroth said:
My 2003 Envoy SLT has 188,000 miles. I noticed it is now rattling or ticking when going over 40mph in 2HI. If you shift it to A4WD or 4HI it is quiet and works as normal. 4 wheel is engaged and works.
It only makes the rattling sound in 2 Wheel drive and once you get over 40mph.
Sadly, no I have never changed the front differential fluid, nor the transfer case fluids. I've seen the axle disconnect part and the actuator motor. I've also read about the encoder motor on the transfer case. Which one would be the culprit? Could it just be low fluid?
It is in A4WD at the moment and not being driven. Is there a way to manually put it in 2HI until I can find the problem?
I've got a couple ideas in mind. They may not be 100% accurate, someone more intimate with the system will probably come along and give a better idea on what to check.
1. Incomplete disengagement of the front axle disconnect, or a part that is loose but seems to snug up when the disconnect is engaged. It's trivial to check the disconnect, just put it in 2HI, jack up the front passenger side, and give the tire a whirl. If it doesn't move, it's probably an incomplete disengagement. It it does but begins making that rattling noise (maybe it's just softer when it's less than 40MPH? Could try spinning the tire fast) then you know your problem spot.
2. Intermediate shaft, though you said 4x4 seems to be working well so I don't see how the intermediate shaft would be an issue. Just never know though. One way to check would be to jack up the front driver tire and give it a good spin. If you get the rattle, it may be the intermediate shaft (again, doubt it if 4x4 appears to work correctly) or maybe the front differential, though that would be expected to make noise full-time. I point to the intermediate shaft as a suspect as it's been the cause of rattle for other folks, and who knows, maybe you've been using 3-wheel drive the whole time?
It seems odd, but yes this part turns the entire time, even in 2HI. It'd just turn in the opposite direction the driver's side tire is going.
Maybe I'm onto something, maybe I've smoked my breakfast today
these are just suggestions to ruminate on while the cavalry takes its time to arrive. As in, while I replace the bulb in the RoadieSignal floodlight.
Welcome, by the way! Why does it seem that since moving away suddenly everyone in Iowa with a TB/Envoy gets on here?
UPDATE: Just saw the post on the "N" showing up. Teaches me to take forever typing
now that makes me curious, however this may be part of the problem or it could be a symptom of an entirely different problem. And you did post this in the right spot.