Hey guys, I just noticed something that kinda has me worried. I have an '02 Escalade, had the front diff. replaced about 3000 miles ago. Now everytime I start my truck up, and put it into drive, at around 5 mph, I hear a RRRrrr sound for about 2 or 3 seconds. Almost sounds like a windshield washer running or the sound the mirrors make when changing from reverse to drive. It only happens when I initially start the truck up and begin to drive. After the first take off, I never hear it again. Anyone ever experienced anything like this?

Might be your suspension air pump. Are you sure it is from the front. Have a friend drive your truck or something. You should be able to keep up to it at five miles per hour...

As said it sounds like the air pump, start it up and stand outside, it should be coming from the drivers side rear if it's the air pump. :)

I thought it was that it first, but I sometimes start it up and let it run for 5 or 10 minutes before I drive it. I would think the air ride would have leveled by then???

I know the noise you are speaking of, my 02 does the same thing, no its not the air pump, that is coming from the back and is easily identifiable. This other sound comes from somewhere under the hood. Mine does it just like you described, usually after I pull out my driveway and turn the wheel to begin to take off. Don't know what the heck it is but doesn't seem to hurt anything and I think its done it pretty much since I've owned the truck.

Piston slap noise?

Piston slap??? LOL, no. Just a very fast RRRRRRR sound, again like the original poster described, kind of like the winshield washer fluid motor sound, but it only does it soon after you take off and then you don't hear it again. I always just chalked it up to some kind of motor adjusting something so I never worried much about it...again, this noise is NOT to be confused with the air pump for the rear shocks.

it wouldn't be you mirror readjusting after you back up out of the driveway would it. Just a shot in the dark..

Hmmmm, interesting suggestion, I'll check to make sure, although it does seem to be coming from under the hood somewhere and the mirror motors are much slower, this sound is very fast. I wish I could make a tape recording of it and post it LOL

I'm glad I'm not the only one with this annoyance..lol. At first i thought it was just the mirrors readjusting, but its not. I hope it doesn't turn into a big deal, doesn't seem to affect anything.

I have the same noise in my 02. According to the Cadi dealer that I bought it from, it is the traction control system. It is tied into the ABS system that assists when the vehicle needs the extra traction. Mine will make the same noise when I drive on very slippery roads...

I have the same problem...But when my niose goes away , my stability system light comes on!!..its gettign annoying and i can also feel in in my peddle..it seems to hold my car back a bit a low low speeds untill the sound goes away. the sound definetly comes from the font and is exactly how u say it sounds..also the sound is getting worse..someone please help!!
thanks guys

the noise you are hearing is the abs pump initializing and building pressure in the system, it is a normal condition of the vehicle

i have a feeling my noise is not normal..when it happen it almost holds my car back from accelerating a low speeds, and once the buzzing stops, the service stability light comes on.
also the sound was never there when i first bought the escalade and seems to be getting louder:S
hmmmmm??

I have the same problem.... it's not the air pump. It's some sort of relay.. It seems to get hung up when you start the truck up with the AC on. Let me know if anyone figures it out.

PS air pump is in the back behind the rear left wheel. This is an electronic sound

the noise you are hearing is the abs pump initializing and building pressure in the system, it is a normal condition of the vehicle


Nope! not normal. I do think it may have something to do with the ABS but definately a relay

ya i agree with you consej. but my does it no matter what. i dont need the a/c on. its weird, i have to reach around 10-15kmph before it happens, its like a reaaaoooor ...reaaoooorr sound and does it 3 times. and i know for sure now its coming from the drivers side, about knee height behind the firewall....
if it is a relay , how would i be able to figure out which one?
thanks guys!!!

I have the same problem as with the RRRRRRR sound and the stability light coming on. Did anyone figure this problem out yet?