My 08 RL with abt 120K keeps loosing AWD whenever I take a turn at abt 35mph, this usually happens when on and off highway exit. Recently I had my alternator(OEM), aftermarket battery terminal replaced as well as aftermarket battery (interstate). Dealer claims this caused by aftermarket battery terminal. Can this really caused the issue. million thx.

I have AWD code 75 and 77 in the MID.

 

Do you feel your AWD going away in the car's road behavior, or are you just seeing it disappear on the dashboard display?

 

when the SH-AWD light comes on, I only get front wheel drive.

 

Check to make sure the fluid is full in both chambers on the rear diff. I would suggest taking it back to another dealer and having them troubleshoot the codes. Replacing the battery with an aftermarket should not have anything to do with these codes.

 

I'm with sOLLEx. Going around the corner is causing low fluid to "lean" and trip a sensor.

 

I'd replace the fluids for sure. I think someone else had a sensor fail causing the same codes.

As for the terminal, it all depends. Usually a bad battery kills an alternator.

 

quote by dealer:

121921 had code 75-1 acc device, 78-1 shawd unit failure 77-1 something in trans, coded 1.00 all of these codes did not come back, had new interstate battery, and aftermarket cable end on positive side of battery, weak battery could cause all these codes, if they come back i would start with cable.

 

Is that what the tech wrote? An aftermarket battery cable is not going to cause just your SH-AWD to go into limp mode while going through turns. After they cleared the codes, how long was it until the codes came back? Was it while driving? If these were just history codes, they would not be disabling the AWD. Like I said previously, check your fluid level/condition. If it is good, then you will have to troubleshoot the codes that keep returning. Could be a faulty shift solenoid valve in the diff, SH-AWD control unit, or even the rear diff itself.

 

The error msg came back within 30min I picked up from them. I'll take check it tmr.
thanks! keeping my fingers crossed.

 

I'm with everyone else to check fluid levels in the diff

 

Did you ever get the SH-AWD issue fixed..I'm having similar issues..Thanks for your response..if anyone has solved this issue- let me know what fixed it..Thanks

 

As mentioned above, the first thing to try is a fluid change in the rear transfer case.

 

Fluids changed by dealership. They're saying it's the rear differential