2000 Bravada Wheel Vibration/Engine Noise

[bpt]

1.) Over the last 3 months or so my 2000 Bravada (95,000m) has started to vibrate pretty harsh when turning at low speeds. It doesn't happen every time, but 80% or so. The wheels shudder when turning sharply, as when into a parking stall; as well as on wider turns - again only at slower speeds. Alignment was fixed two months ago.

2.) For several months now I've been hearing a high pitched whine coming from beneath the floorboard, near the center or rear of the vehicle. It occurs when I'm accelerating, mostly through the city, and never makes the noise(or I can't hear it) when I'm on highways. This noise doesn't always occur, and I can't seem to find any patterns like temperature, type of road, whether I'm pulling something or not, or how fast I'm accelerating. It will make this noise sometimes if I floor it, and sometimes will do so when I gradually speed up. Once I get to about 45 mph the sound subsides. It sounds very harsh though, almost as though I've got a hole in the exhaust - but I know it's not that. I feel like I've maxed out the RPM's even though I'm running around 2-3,000 under a gradual acceleration.

Any answers from anyone?

[MT-2500]

Welcome to AF
I would suggest a good inspection by a good repair shop on this one.
Look wheel bearings and drive shafts and engine mounts and even engine running over good on it.
Is this a 4w or all wheel drive and if so what transfer case and engine and transmission?

[Chris Stewart]

I agree with MT-2500 as the noise on my '97 was the catalytic converter breaking up, it's going to be a shop job and while it's there, a transfercase fluid change to the GM Autotrak II blue replacement fluid will help address your wheel binding/vibration until we get a procedure to manually unlock the encoder-motored Smartrak transfer case.

[bpt]

Thanks for the comment posts guys. To answer a few of your questions - I just replaced the catalytic converter about 3 months ago, about the same time I had the alignment done. It's all-wheel drive (SmartTrac) and has the 4.3L Vortec engine. Not sure on the tranny or transfer case types, but I'll post later.

[muddog321]

AS stated the Bravada had transfer cae clutch pack binding so a GM bulletin on replacing the fluid with blue, driving 100 miles, chaging again and hope that fixes it. As for the exhaust noise 99-01 had the secondary air injection so lookk in the "How To" section on that whole mess - both my 99 and 01 had many problems/rust outs/burn thrus on those quality parts!

[smacit2ya]

The low speed turning, shudder, lock issue is very common with plates in the transfer case binding, as the previous gentleman mentioned. They tend to get a varnish like build up on them, and the only true fix is disassembly, cleaning and fluid change. The change it, drive it change is the cheap way the dealer wants to do it. It won't. Insist on disaasembly if they are paying. It will return, unfortunately either way.

There is a mod I saw that lets you put in a toggle switch to bypass the fuse for the smartrak. Even simpler, you can simply pull it and see if the problem goes away. Trying to remember on my 2000, but I know on my 02 theres is 1 in the box under the hood, and 1or 2 in the box under rear seat. It might be 2 up front 1 in back, check the chart in your manual. You end up disabling the encoder motor, turning it into a RWD vehicle. Putting the fuses back gives you your AWD back. It does not hurt anything, actually improved my mileage when I moved from MA to Florida and run my AC all the time (12 fricking mpg). I only put them back in when it rained.

Now if you do that, and still have those thumping, locking noises with turning, you more than likely need a front end rebuild. Sounds like a loud pop or snap during the turn. Alignment should have picked that up. The Chevy, GMC, and Olds are notorious for destroying ball joints, tie-rods, etc. My 2000 needed the whole setup ($1200 plus !!!!!, thank you extended warranty) at 58k miles.

More good news for you (I know this sucks), the whine might be covered under a TSB for shaft seal. Maybe its covered.

These trucks have driven me crazy, but between my Dad and I we have had 4 (97, 00, 02, 04) bought from his neighbors dealership. They let me spend time in the shop, so I have been lucky to learn alot. I even found some of the TSB issues they did not know about! Mine is gone now, replaced with an Audi Q7. Would have bought another, but not as Buick or SAAB. Do like what they finally did with that god awful grill on the OLDS with the new Buick, and the rear quarter windows. Really sharp. Just couldn't buy Buick, not at the money they want, when the Audi was so close price wise.

Now, if you get it all fixed, plan to keep it and want to make it look SWEEEEET, I have set of 20's with Goodyears I took off my 02 before it went goodbye. 3500 miles on them. Need the space in the garage, so they gotta go........

Good Luck!

smacit2ya