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Old 02-04-2018, 04:10 PM   #86
lemming
Western Anomaly
 
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Join Date: Oct 2003
Carmudgeonly Ride: White Orca
Posts: 16,582
Quote:
Originally Posted by rumatt View Post
I read enough to finally understand the JGC AWD sytems. Multiple of the web sites summarizing them are out of date, including the one I linked above. Here are the facts:

As equ says, QD2 (Quadradrive 2) is based on QT2 (Quadratrac 2) - they share the identical 2-speed transfer case etc. The only difference is how the transfer power side to side.

QT2 controls power side to side using BLD (Brake Lock Diffferential - ie the brakes)
QD2 adds in a pretty cool e-LSD that has the ability to send 100% of power to one wheel, effectively acting as a locking diff.

QD2 from the WK generation (2005-2010) had 2 e-LSD's, front and rear. But the 2011+ WK2 generation has 1 e-LSD in the rear only, and keeps the BLD for the front. The JGC purists are annoyed and think it's BS they called it QD2 with just one locking diff. People claim that Jeep engineering said "the WK2 traction computer is so much more processing power (quicker response) and with updated algorithms that front ELSD is of insignificant benefit, not worth its disadvantages. "


Here's a great video comparing the QT2 and QD2 systems on WK and WK2 JGC's. It compares:

Open diffs: FAIL
WK + QT2: Wheel spin, but BLD clearly effective
WK2 + QT2: Less wheel spin than WK. BLD definitely improved
WK + QD2: eLSDs very impressive. Looks like a pure locker.
WK2 + QD2: Not included. I was hoping to see how the front BLD on the QD2 performed together with the rear eLSD.




Despite missing a front locker, this WK2 2014 JGC seems to pass the diagonal test with flying colors - almost no wheel spin. The video doesn't specify, but I assume it has QD2.


And a fun torture test really showing off the locking ability of QD2 on a 2006 Jeep Commander
super fascinating. cool to see what is effective compared to full mechanical hardware for differentials.

i've never worried about getting stuck in the JK and i think it's open diffs on both axles.
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