NP247 and Quadra Drive noise and binding fix

[Hurricane 4x4]

Lots of people begin to have issues with their Quadra Drive or Quadra Trac II systems binding when turning sharp corners and making a loud growling noise. I talked to the techs at the dealership today and learned a trick which I had not heard before.

This only applies to the 247 Transfer case found in Quadra Drive and Quadra Trac II grand cherokees.

T-case: Low fluid level, improper type of fluid, and old/dirty fluid can cause the progressive coupler to engage and chatter while turning sharp corners, such as in a mall parking lot. The correct fluid is only available from the dealer, and is ridiculously expensive, but you must use it. When you go buy the fluid, make sure it is made by mopar and has "247" transfer case listed on the label. The "trick" is to add limited slip additive to the fluid. There is no TSB on this but I was told by 2 techs at different dealerships to use it.

What You Need
2 Quarts of Mopar 247 T-Case fluid.
1 bottle of Mopar Limited Slip Additive (friction modifier)
10mm Allen Socket

1. Drive around to get the transfer case warmed up. Do some Figure 8's

2. Remove Fill Plug

3. Drain transfer case fluid, replace drain plug. Careful not to overtighten

4. Fill it. Put half of the limited slip additive into the first bottle of t-case fluid (easier to get it in there) and dump the whole quart in. You will only need to use about 3/4 of the next bottle, fill the case until the fluid starts to come out of the fill hole. Once full, let the excess fluid drain out of the hole for a few seconds until it is just a trickle, then re-install the fill plug.

5. Go do some figure 8's. Get the case nice and warm and it may chatter for awhile, but hopefully your problems will go away and never return.

If you think you changed your fluid recently enough, you're probably wrong. I was told that the fluid can become suspect after about 20,000 miles.

If You Have a Leak
My t-case was leaking at the output shaft seal. The seal is easy to replace.
Mopar part# 4897298AA

1. Remove rear driveshaft, and slide it out of the t-case output. Careful to set parking brake and chock wheels as "park" does not work when the driveshaft is disconnected.

2. The old seal is now exposed. Hook it with a "seal puller" tool and pry it out of there. Careful you are prying on the seal and not digging into the aluminum inside the housing. It should come out somewhat easily.

3. Tap the new seal in place. You can do this easily with just a rubber mallet.

4. Re-install driveshaft. Careful there is no dirt on the surface that is to seal with the t-case.

One more word... guys at the dealership said the rubber access plug located on top of the output shaft retainer can leak and make it look like you have an output shaft leak. The fix is to remove the rubber plug, clean it, and put a little rtv on it when you re-install. Don't go crazy with the rtv as you don't want any floating around inside the transfer case.


Quadra-Drive axles

Quadra Drive models came with the same progressive "vari-lok" device found in the 247 t-case, installed in the front and rear axles. If you are having growling noises and binding issues, your most likely culprit is the transfer-case. however if you do the fluid change and limited slip additive and are still having issues, your vari-lok axles are probably acting up. In my case both the t-case and rear axle progressive limited slips were making noise. A fluid change and limited slip additive in the axles if you have Quadra Drive or the optional vari-lok rear can really quiet things down.

Change the fluid in the axles. Use 75-140w synthetic gear lube, and add a 4oz bottle of mopar limited slip additive in each axle. I can't remember exactly what the capacities are in the axles, but you can find that in your owners manual. The axles are just as sensitive as the transfer case is to having the correct fluid and the limited slip additive.


If you do all of this, and you are still having issues, you're probably screwed. The progressive coupler on the 247 is actually easy to replace and can be done without removing the t-case from the vehicle, but it is $700. If you can find a junkyard one you might do alright, but there is no guarantee it won't have the same problem. As for the axles, the progressive couplings are more difficult to replace and also very very expensive. You are probably better off swapping in another axle or t-case rather than messing with it.

EDIT... I found a good supplier for OEM jeep parts. The 247 Progressive coupling kit is on my website. Price $370. Comes with all seals etc.. Can be replaced w/o transfercase removal.

[iluvtruenos]

Your writeup is out-fucking-standing.

I would like to comment on one thing though:


Loosen the fill plug first, then the drain plug. It's much better to have old fluid than none at all.

[Hurricane 4x4]

good thought. I know I've heard that before.. And it makes sense anytime you do a job like this. Plan to leave a "way out" so a mishap like a stripped drain plug dosent leave your dd useless. I feel the drain/fill plugs on the newer np cases are much less likely to strip than the older ones, but I still recommend that approach.

[Hurricane 4x4]

changed it

Something you guys might be interested in... the service manager at the dealership said that in 1999, before mopar came out with their own, special transfer case fluid, they were specifying ATF in these transfer cases. They told me the fix they used then to stop them from binding/chattering was to add a little B&M trick shift to the fluid.