Wh Grand Cherokee Common Faults And Issues
 

All limited and CRD till end 2006 build had QD2, after that was option only. Bash plates matched the QD2 option for fitment.

Always double check for the badge under the shifter and 12 bolt rear diff cover to be sure.

My WH GC.
 

Thanks for the welcome, My wh I bought as a 2007, I later found out it was actually built in 05, it is a LTD 5.7 QD and i love driving it, Goes like a cut snake but man does it love the petrol when I hook up our cavaran 25-30 Ltrs per 100 klm and that is sitting on about 90 K,s in 4 and not using cruse, I have only put it in low range twice and when I do it makes a grinding noise from the front and the service 4wd light comes on. Also could anyone please tell how to get problem codes from the computer and how to clear perform service message on dash. Any help will be greatly appreciated,
Thanks, Ferret.

Does low range actually engage? There is an electric motor that switches the transfer case from high to low, when it operates it makes a growling noise, I suppose it could be described as a grinding sound.

Being a 2005 5.7 limited I would think its a QuadraDrive II.
If it actually goes into low range there could be a problem with the front or rear electronically controlled limited slip differential wiring, broken or doggy wiring can cause this warning.

Have you had the N23 update? this causes the "Service 4wd system" to appear on the dash but there should be no noise when you attempt to switch to low range as it disables the shifting motor.

If low range does not engage I feel your best option is to go to a Jeep dealer & get them to read the codes.
Whatever you do DON'T let the dealer preform the N23 update if it hasn't been done, this will seriously stuff up low range if you let them.

A Superchips Flashcal (3570) or Flashpaq (3872 or 3870) will read your fault codes (search eBay)

You must read the N23 thread
http://www.ausjeepoffroad.com/forum/...d.php?t=128329

I use this one, reads and deletes codes ...uses your laptop.
https://www.autoenginuity.com/produc...mily-ei04.html

What sort of figures do you see on the dash when not towing?
Also what mods (tyre size, extra weight, etc.).

I had a significant improvement in fuel economy (also a 5.7 hemi.) after I replaced the EGR and PCV valves (at around 80,000km.).
The correct viscosity oil is important too - It really needs to be a 20wt for the MDS to function correctly (although MDS is disabled when not in Drive, or if Tow/Haul is activated.). I use a 0W-20, most of the hemi guys here are using that or 5W-20. Some are using Penrite's 0W-30, and probably some still using 5W-30 or 35.
There's a lot of misinformation around about the oils (I've heard incorrect advice from "professionals" for literally every oil in the vehicle.), so do a search here before you pay for anything :)

I've found that the cruise control does a good job even when towing, I mostly do long trips in mine and haven't noticed any increase in consumption using cruise. I just help it out with things it can't predict (like building up a bit of speed before hills.).
Also using the Tow/Haul button in Drive tends to work out a bit better than keeping it in 4.

Is this when driving in a straight line or when turning? Is it on tar or gravel?

Does it actually go into 4lo ( dashboard light )?

Does the 'service 4wd light' message go off on the next restart?

Never put it in 4lo on tar as you may get Transfer Case windup.

The question is a year old!