i've got something really weird going on with my h3. when i come to a stop the vehicle bucks like my brakes are pulsating but there's no feedback in the pedal or at the wheel. it doesn't seem to happen right away, it's as if something's heating up after driving for a bit. it gets so bad that just rolling up to a stop in traffic will cause the nose to buck up and down. it's speed, not rpm, related. as if it happens per revolution of the wheel.

a buddy said to check my diff fluid, which i was planning on changing anyway. he's also got an acquaintance who "claims" to have hummer mechanical experience and he said there's a known issue with the transfer case that causes this same symptom. he said it was something about the tc randomly locking and unlocking at low speeds but in my case this happens at highway speeds too if i have to honk on the brakes in the fast lane for any reason.

any thoughts? if so let me know what you're thinking.

 

Hi,
Just to clarify...
*engine smooth accelaration (NO loping)?
*After the brakes seem to heat up this begins?
*All oem stats or aftermarket addons?
Chris

 

hey chris:

-engine runs smooth as silk
-it doesn't happen when i first start up and drive. my assumption is something is heating up. whether or not it's the brakes is where i'm coming up short. this would be only too logical except i don't feel any thumping in the pedal or shimmy in the steering wheel.
-bone stock 2006 h3

please keep in mind that it seems to be every rotation of the wheels. also because of the way the nose is diving i believe the problem is up front - seems logical but i may be wrong. it so seems like the brakes heating up but the pedal and wheel stay so smooth.

thanks for anything you've got for me.

 

That sounds like a transmission problem, bucking and surging or a throttle problem. Hard to diagnose something like that over a forum really. Transfer case locking generally makes it really hard to turn.

 

What you are feeling doesn't feel like warped rotors?

 

Im going to lean toward brakes. Ive seen the sleevs on the front brakes corrode and rust so as to bind. The rotos themselves could have hot spots. As was stated the 4wd engaging and dis would make for hard steering. This would also wear on the t-case. Id be cautious.
Chris

 

One side thought.... the pulsing may be abs related.
Chris

 

from the passenger seat it feels like brake pulsation, but from the driver's seat there's no feedback at the pedal or wheel (this is what i'm really stuck on). no other issues with idle or steering. i thought about a sticky caliper heating up and causing the a rotor to distort but not feeling it in the pedal is the only reason i question whether or not it is a brake heat issue. i would think if it were any type of electrical or abs issue it would do it from the get go rather than driving normally for the first 5 or so minutes before acting up.

hot spots: i wouldn't feel hot spots on the rotors at the brake pedal, right? but wouldn't i feel it at the wheel? wouldn't it want to pull to that side? this is along the lines of what i was thinking. but again, the way the nose bobs up and down i find it hard to believe i wouldn't get SOME kind of feedback at the wheel. hmmmm .... i think i'm gonna pull it apart and check the way bolt sleeve. if these are binding up causing excessive heat build-up. do you think freeing them up and greasing them would cure this? i'd make sure there were no burs or pits to bind up before re-assembling, of course.

thanks for the suggestions guys and i'll be sure to put these things on my list of things to check.

I FRIGGIN HATE INTERMITTENT PROBLEMS!

 

using the grease may work

 

i'll lube them up with some anti-seize. if that doesn't do it i'm afraid we're off to the gm dealership.