Hi All,

Okay, so I had that T-Case put in from a 2010 RRS, no probs after the re-calibration. Last night it snowed near my house; maybe 3" or so. Just enough to go take a night drive and play around. I didn't have any real traction issues. I did notice, though, that in all TR modes, my center diff was not (shown as) locking. I even put it in Rock Crawl and spun my tires intentionally and no lockup. I don't know if the diff isn't locking, or the display simply isn't showing it (locking).

Any ideas? Run the TCCM calibration again? Is there some other routine to consider? General thoughts?

Cheers,
Houm

 

If there is an issue, you should have codes. Also if I recall, the status on the info display is not the actual current condition of the center or rear diff but is what is being commanded. Meaning if the truck wants to lock the center diff it will and the info display will show it locked because that is the expect operation. So the display is not feedback that is observing how they are operating, like an external sensor.

 

Thanks. All I know is that the center diff icon should show "locked" and turn green, and it isn't doing that. I think one thing I could do is get it on a lift with someone inside to give it gas and see if wheels are spinning front and rear.

Does the vehicle have to be on level ground for the TCCM calibration process to be done properly? I wasn't. Maybe it's something goofy like that.

 

No, doesn’t need to be on level ground. You can run the calibration again, no harm in it. There are two TCCM calibration routines —clutch calibration and actuator position (or something like that). Did you do both of them?

That was some real snow we got. Well over 4” at my place and it was a sopping mess. Trees down everywhere. LR3 and Hill Descent Control got my out of my place and to the airport, though. I drove in Grass/Gravel/Snow for a few miles and never had my center or rear locked engage (per the 4x4 info screen). Like Dakota says, the screen only shows lock/unlocked, but the diffs are variable locking so there’s a lot of in between.

 

That's good feedback, thanks. Yes, I did do both routines. When I went driving there was about 4" here as well (Mukilteo). I suppose it could be that it simply never needed to lock. I put it in Rock Crawl too, as a test, though....and it still never locked. I guess maybe it still just didn't need to? I suppose I will just do nothing until I can get it on a lift in 2 weeks and see what happens when wheels start spinning in the air.

I turn HDC off in snow. I have had HDC induce a spin - in snow - in the past. In my opinion if you have to go slow it's better to just use 4-Lo if it's slippery, especially on really steep hills. I've even slipped a little on a steep hill (between Phinney and Greenlake) using just 4-Lo. That is when I realized that with the LR3's gearing, 1st gear (in Lo Range) can just be too slow. I shifted up to 2nd and was fine the rest of the way.

Anyway, thanks!

 

I forget what percentage of lock is commanded to be considered "full lock" and trip the icons. The LR4 info display on the second gen actually shows how much lock is happening. In quarter increments I believe? So there is that too. Its possible you had, lets say, 20% lock working for you and did not know it.

 

It's possible...also possible that it was working just fine and the algorithm is different on the '06 and on, compared to my '05.

I took my '05 out today. Did the TCCM procedure. Before and after, the display worked the same. The diffs are green once a TR mode other than General is selected and while I had to work to get the center diff to lock, I could. The snow was also slushier/icier than the powder I drove the '06 in on Wednesday night.

As for the shifting....it seems better, as far as the shift from 2-1 and retaining 1st rather than spitting it out and going back to 2nd. It still does it, but instead of 95% of the time, it was more like 10% of the time. Not sure the TCCM Routine had anything to do with that at all.

I'm tempted to reset the Transmission adaptations. Any downside to that? Could it mess up the B034 fix to the CA stop THUMP! ???

 

Closure on the '06 display behavior:

There are still piles of frozen snow on the streets/alley around my house, so I thought I'd try it again this time "climbing things" and sure enough, I achieved lock-up!!! So that's the end of this saga.

 

Sounds like you just needed to hit the right condition . Nice work!

 

Thanks....I'm relieved. I can't believe I got out of that bad T-Case situation so cheaply/easily.