So the linkage let go on my truck while I was descending a steep hill in low range with HDC activated. Had not used the linkage in almost a year but last time I used it descending Mt Ascutney the low range and HDC worked flawlessly.

Upon reaching the bottom of the hill I shifted the transmission into neutral while maintaining a speed of between 5-10mph. Then I deactivated the HDC and proceeded to shift back up I to high range. I noticed some strange mechanical clunking noises periodically. The linkage appeared to let go and the high/low shifter feels almost loose; by this I mean that when I try to push or pull the high/low shifter in high or back in low, it feels effortlessly. I tried shifting into lock then unlock and there is still resistance as you would expect but no resistance when trying to shift between high and low. Despite pulling the shifter into the high position the truck is still in low range.

Last year I drained the transfer box. Cleaned the inspection cover plate and applied a new bead of sealant around the perimeter. Refilled the transfer box with Mobile 1 gear oil. Besides small droplets no known major leaks from the transfer box. Recently the transmission was removed and professionally rebuilt with a master rebuild kit. As far as I know the transfer box was not torn apart or altered.

Iam surprised as the truck is rust free. In any case I dropped the truck off at a local shop over a week ago and they are stumped so far. They checked the cdl locker linkage and found no issues. I told them to inspect the high/low linkage. Is this a common failure point on the late model Discovery transfer box? Could the solenoid cause these symptoms or is a broken linkage the most probable culprit? Could this indicate that the transfer box itself needs a rebuild?

 

If the solenoid fails, the shifter won't move anymore, so it's not that. It sounds more like a broken cable.

 

Broken cable, broken clip that holds the cable (on either end), or something inside the front of the TC let go. With 2 people it should be fairly quick to diagnose (one inside & one outside under it with a mirror to watch the cable at the top or bottom). Also to verify if it's still connected.

 

pull the center console and it's much easier to diagnose the linkage. I had the hi/low connector piece break earlier this summer, could not diagnose by myself from underneath the vehicle.

 

The shop finally made some progress today. They said the linkage does not appear to be broken or bent but that unclip that secures the cable to the transfer box on the top end had broke. They replaced it and put the access panel back in place. Upon attempting to shift the linkage from low to high they said the linkage is really stiff. I asked them if they had the transmission in neutral and they said yes but that the truck is in the shop as they try to engage high range. I told them to lub the linkage at all the points then to take it out on the road and maintain a speed of around 5-10 mph, then shift into neutral and attempt to disengage low range. They will get back to me.

Not sure of a stiff linkage is an indication of bad linkage or bad transfer case or just lacking some lub. Any thoughts?

 

@TRIARII Mine is stiff if I do not use it regularly then it smooths out, they seem to get grumpy if not used once and while.

 

Have them disconnect the linkage from the transfer case and see if it's still stiff. It's not uncommon for the cable to bind; supposedly, you can take it to a bike shop and they can force lubricant into the cable.