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Front End Grinding... I Searched

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after i went cross-eyed reading old posts and just about smashed my head off about 5 different GM service counters, i figured i'd turn to the REAL experts:


i'm getting a mild grinding/ whining noise out of my 07 1500HD in auto 4wd mode on deceleration. when i let off the throttle the front end starts making the noise. i'm wondering if this is normal and it's just the front differential being locked in (the HD has lockers front and rear supposedly, according to my build sheet), or if there's something gone amiss that i need to address with the dealer. i have the extended warranty and i've talked to the techs, but they apparently have next to no experience with diagnosing problems before they're at a catastrophic failure. i guess GM only trains techs to R & R now rather than execute preventative maintenance... heaven knows that might actually take some though or something.


main reason i'm asking is that my truck gets used as a truck... i tow and haul a lot with this thing and i don't want to end up stranded with a grenaded front diff or transfer case while i'm several hours from home, especially since i don't know anyone with a bigger truck that'll pull mine except my workaholic neighbor.


well, now that i'm done with my rant, i'll pass the conch to anyone who may have any input... you folks likely have a whole lot more wrench time under these bad boys than i have, so any insight you all can provide would be greatly appreciated.


thanks in advance from both me and The Duke (my truck) and have a good one!

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Since the SS is full time AWD or 2WD depending on the year, nobody here is likely to be able to relate to your problem directly. The HD has a different transfer case and different axles/carriers, that equals nothing to relate to here.


Generally speaking though, noise out of a diff is never good under straight line driving in accel or decel. Turning in 4WD, the HD does tend to make some noise though, but nothing super loud until you get under about 10 MPH or so. Good luck! :cheers:

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My AWD does the same thing under Decel. Remember you said you have it in Auto 4wd, so it will act as the SS's AWD a bit, as in the front axle is engaged, kick it over to 2Hi and it should stop.


In auto 4WD, the front wheels should not be enabled. They should only come into play if the rears slip.

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on the e-diff trucks, the Auto mode locks in the front diff, but does not engage the transfer case unless the rear wheels slip. it happens at virtually all speeds but on decel or neutral throttle only. no noise when turning.


it doesn't make any noise when in 2 hi and it makes a normal gear-whine noise when in 4 hi. haven't noticed the front diff noise, but it may just be that i can't hear it over the engaged transfer case. this symptom only presents itself when in auto 4 on decel and neutral throttle.


thanks for the input though guys... i appreciate it. i figured someone might have a tow rig or something as a daily driver with all the trucks i see extensively modified around here. hopefully you guys caught that article in (i think) hot rod last month about the LQ9 build they did and pulled 751 horses out of it with a s/c, heads, cams, LT headers, and a wee bit of wiper fluid :drool: motor was absolutely ridiculous... and i wondered for a moment if the s/c would require hood modifications in my truck. :devil:

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