What's different about AWD ?

[Gabe]

Here's the answer :


AWD models have a 55mm factory offset on the 18x7.5 wheels, whereas the RWD models use offsets in the 15-25mm range.

The AWD models have the front brake calipers mounted on the front of the rotor, the RWD models have the calipers on the back side of the front rotors

The stock AWD suspension sits 1" higher than corresponding RWD models.

This can be "fixed" via Eibach springs (2" total drop after settling), KW coilover kits, and the soon-to-be-released CW Motorsports coilover kit, which I will be looking into getting as soon as some are on the road and people are happy with them. The coilover kits are adjustable for drop and the CW will also be adjustable for ride smoothness (not sure if the KW is)

The car's floorpan, the engine oil pan, and front struts are also different on the AWD models.

The floorpan has a hump on the right side so the transfer case can fit.

The front differential is mounted on the right (passenger) side of the vehicle next to the engine and has an intermediate shaft that goes through the oil pan and connects to the left axle shaft (the right shaft connects right to the differential).

The front struts have a lower "fork" which connects to AWD-specific knuckles and the fork allows the axle shaft to go through it to connect to the center of the wheel


The front brake set-up (shows my current rotors - drilled/slotted R1Concepts) :




The front diff, oil pan, intermediate shaft :




The AWD front suspension:


(ignore my leaking CV boot )


The transfer case :

[BOS/SRT]

sweet gabe! thanks for the info! i'm going to have to buy you a lot of tooth brushes to get all that dirt off the underside. lol were you leaking oil?

[Gabe]

Originally Posted by BOS/SRT sweet gabe! thanks for the info! i'm going to have to buy you a lot of tooth brushes to get all that dirt off the underside. lol were you leaking oil?

Hehe ... that pic with the fluid dripping down was taken during the heads/cam work, so that's actually coolant .... the lovely Mopar coolant ... lol

[BOS/SRT]

oh.. btw, did you ever figure out your power loss issues?

[Gabe]

Originally Posted by BOS/SRT oh.. btw, did you ever figure out your power loss issues?

No, not yet ... still need re-dyno-tune .... meanwhile, I started using a "Silver Box" from Performance Electronics - a vendor on lx ..... the box get wired into the TCM wiring and changes line pressures ... basically an electronic shift kit.

It has a switch with positions 1-6 on it, 1 being stock, 2-6 being progressively firmer shifting ..... meanwhile, all settings 2-6 eliminate the awful delay from R to D or D to R

[Mik3y]

Quick question, your R/T is true AWD, right? The reason i ask is i recently found out the GCSRT8 isnt a true AWD.

[Gabe]

Originally Posted by Mik3y Quick question, your R/T is true AWD, right? The reason i ask is i recently found out the GCSRT8 isnt a true AWD.

The 05-08 systems use a fixed 38/62 front/rear torque proportioning, but when I'm on ice or snow if I shut off the ESP by pushing the dash button, I can then punch it and only the rear wheels spin.

Once I re-engage the ESP the front wheels kick in shortly after the rears spin ... so it's very much an ESP-dependant AWD system ...

The new 09+ system is RWD until a rear wheel slips and then it sends power to the front .... the front axle is automatically engaged if Autostick is being used, or if outside temp is below 38-40 degrees, wipers on ,,, something like that ... various parameters need to be met for it to automatically be engaged.


But regardless of which system the car has, it still uses open diffs frton/rear and in the t-case ... so it's still traction-control dependant ...


The AWD system in the Jeep is actually very similar in operation but uses a stronger t-case and axles ...

[DaBlackPearl]

Good info...Thanks for sharing Gabe.

[chargerchad]

this is a nice write up and some good info, thanks for sharing Gabe!