hi im mark i have an 07 monte ss i have the same trac problem that is floating around the web. i have had my hubs replaced and theres the same problem. there is a hissing noise once the service trac light comes on also. if anyone could brainstorm with me i have some more thoughts on this and would love to get my car back to par. i also have a rattle or chatter goin on during low speed rpm, however not during the idle. egr? or evr?

 

Hey welcome Mark, there are some members on here who could possibly help point you in the right direction and help resolve your problems....

 

Welcome to the forum.

When were the hubs serviced? As the problem sounds suspect to a failing hub....

Also, might want to get a scan tool that can read the ABS computer. If you get one that does, it might have ABS codes to look at.

My experience has been if you go for the cheapest brand hub assemblies, expect about 1.5-2years of service. Hence why I have been recommending Timkens, made in the U.S.A, not the cheapest, not the most expensive, but reasonable with a great track record of long life.

 

Welcome to the Forum

 

hubs were replaced a month ago, it shifts hard or lags on the start but its intermittent.

 

Welcome and enjoy the forum!

 

Welcome to the forum!

 

Welcome to the Forum ..

 

Welcome!

 

Best thing to do is:
- Jack the car up
- With the wheel on, grab the top and bottom, see if it has play (wiggles). Repeat same steps for left and right. I also try doing it diagonally. If there is play in all directions, it have a bad wheel hub.
- Again, with the wheel on, car in neutral, attempt to spin it. Listen for signs of that noise.
- Wheel off, inspect the brakes. Are the pads worn down and a warning tab on the pad making contact with the rotor?
- Is the axle nut on tight?
- Are the bolts holding the hub to the steering knuckle tight?
- Signs of debris in the path of the brakes or anything else that rotates with the wheels?

It is possible if they were cheap-o hubs they are bad (unusual to happen in a month, but possible). I assume that when the hubs were originally changed a month ago, the noise went away? If so, I'd explore bad hubs again. If not and the noise persisted, I would inspect everything else. I assume the noise only happens when the car is moving?

As for the trans shifting issues, some people have seen minor issues develop with these transmissions (I don't know much about transmissions, so I can't say how big or small the issues are). First step, check and ensure it has enough fluid. Also, pay attention to the manufacturer's suggests fluid/filter change intervals. I do NOT recommend using a Jiffy-Lube style Transmission Fluid Flush (people who have trouble with a trans after a fluid change are normally those who had it flushed). I recommend pan drop, fluid/filter change. For me, I change every 100,000 miles or sooner. Going past 100,000 miles between trans fluid and filter changes can be problematic to change the fluid at that point.