Join Date: Jan 2010
Location: West of the Mississippi
This thread is deteriorating rapidly. FM in the transfer case? Seriously? Never, ever, put anything in an NV247 t-case except Mopar OE fluid. They are very sensitive.
First, how many miles on your WJ?
A few things about quadra drive: You have two critical components that fully operate the system (1) the transfer case progressive coupler which engages it detects the rear wheels spinning, and (2) the vari-lok differentials (clutch based limited slip) in both front and rear that detect wheel spin between tires on the same axle. Given your first symptom that the front wheels are not spinning at all, I'd say that something is going on with your transfer case progressive coupler. As recommended by others, put fresh new OEM mopar NV247 transfer case fluid in there and nothing else. You should start seeing the front wheels engaging on your grass test. If not, then the coupler is toast. This could happen with very high mileage WJ's.
Your second symptom is that only the rear passenger wheel spins, says there is something that's going on with the differential. Also, as recommended, it could be as simple as just needing some friction modifier; however, who knows when the prev. owner serviced the diffs last. Get the correct diff fluid for front and rear, add the correct Mopar FM (I use Ford Racing FM and it works too, but use Mopar to be safe). You should see two wheel spin out marks now on the rear. If this doesn't fix it, then your clutch packs are toast. This doesn't happen often on vari-lok diffs because the clutches are not pre-loaded like other limited slips and don't wear out as fast. But it's possible. They are not serviceable and you'd have to replace the vari lok with a new unit.
I know hind sight is 20/20, but you should have tested the 4wd system out before you bought your rig if you need it for winter snow driving. You are going to spend a couple hundred bucks on Mopar fluids for this. Let's hope it pays off.
2004 WJ 4.7L, 1959 CJ-5, 1990 XJ Limited (sold), 1996 XJ (sold), 1989 YJ Wrangler 4.2L (Sold)