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Ask Ivan Alvarez Your Own Question
Ivan Alvarez
Ivan Alvarez,
Category: GMC
Satisfied Customers: 42
Experience:  lead technician at Performance Tire and Automotive
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My 2008 yukon SLT has an intermittent vibration during idle

Customer Question

My 2008 yukon SLT has an intermittent vibration during idle and sometimes during braking but only at slow speeds. I've recently had the front rotors replaced and checked however that did not solve my issue.
Submitted: 1 month ago.
Category: GMC
Expert:  Ivan Alvarez replied 1 month ago.

Sounds like you might have two separate issues. Where do you feel the vibration at idle?

Customer: replied 1 month ago.
I can feel it through the brake pedal, you can sort of hear it as well.
Expert:  Ivan Alvarez replied 1 month ago.

Does it sound like a humming noise? Do you have any warning light that come on along with vibration?

Customer: replied 1 month ago.
maybe a little bit of a hum. no warning lights or check engine. I have a bully dog and the last time I had a check engine light it said no dtc.
Expert:  Ivan Alvarez replied 1 month ago.

Ok lets start by trying to eliminate the abs system. In the fuse box under the hood pull the fuses that are listed as abs. Then see if your vibration at brake pedal is gone.

Customer: replied 1 month ago.
I'm at work and will do this as I'm leaving and respond. Sorry for the delay.
Expert:  Ivan Alvarez replied 1 month ago.

No problem.

Customer: replied 1 month ago.
i was looking in the fuse box under the hood and according to the manual it's fuse 2, there is no fuse 2. maybe i'm confused
Customer: replied 1 month ago.
it looks like the fuse has already been pulled
Customer: replied 1 month ago.
its actually 9
Expert:  Ivan Alvarez replied 1 month ago.

Yes it will be fuse #9 and fuse #61. Both are for the abs. Doing this might make your abs light turn on but your brakes will still work except the abs.

Customer: replied 1 month ago.
ok so I pulled both and my antilock brake light is on but so is my regular brake light
Customer: replied 1 month ago.
the traction control light
Expert:  Ivan Alvarez replied 1 month ago.

those will go off once you put the fuses back in. Did the vibration go away at the brake pedal?

Customer: replied 1 month ago.
no it didn't
Customer: replied 1 month ago.
I've put the fuses back in
Expert:  Ivan Alvarez replied 1 month ago.

Ok after installing the fuses turn the vehicle on then off. then on again and the brake lights should be off.

Customer: replied 1 month ago.
They're off
Expert:  Ivan Alvarez replied 1 month ago.

Know that we ruled out the abs system lets check some things on the steering system. Check the fluid level of the power steering fluid. this reservoir will be on the drivers side usually close to the power steering pump.

Expert:  Ivan Alvarez replied 1 month ago.

This systems brake system has a hydro boost for the brakes. The power steering pump supplies pressure to the hydro boost for your brakes so if the pump is failing it would make sense to feel a pulsation at the brake pedal.

Customer: replied 1 month ago.
the engine is hot, the level is up to the bottom 3rd I'd guess, where it says add. according to the manual you're supposed to let it cook but the dipstick says hot level or something similar at the top. does this mean if it's hot it should be all the way to the top of the dipstick?
Expert:  Ivan Alvarez replied 1 month ago.

It should be up to the top line with the engine off. This level doesn't really change much with engine hot or cold.

Customer: replied 1 month ago.
I should add some power steering fluid to it and see what that does
Expert:  Ivan Alvarez replied 1 month ago.

Once you top off the fluid level check to see if the pulsation is still there.

Expert:  Ivan Alvarez replied 1 month ago.

If the pulsation is still there then I would recommend that you replace the power steering pump.

Expert:  Ivan Alvarez replied 1 month ago.

Turn the vehicle on then put your foot on the brake and start to turn the steering wheel. If the pulsation gets worse while you turn the steering wheel then that's another sign you have a weak power steering pump.

Customer: replied 1 month ago.
does it matter what brand of fluid I use
Expert:  Ivan Alvarez replied 1 month ago.

No.

Customer: replied 1 month ago.
topped it off, the vibration does not get worse when I turn the wheel left or right with the brake on. I just left my house and when I started the truck I noticed that I could feel the hesitation in the seat
Expert:  Ivan Alvarez replied 1 month ago.

It still seems like a power steering pump issue. By what you described at low speed driving also points to the pump. At higher speeds it would not be noticeable because there is not much load on the pump.