Growl when in reverse with brake applied...

[Yetti]

I am not sure as I haven't been under one in years but I would look at the rear trans mount to see if its in tact. the rubber might be torn out and its grounding againest the chassie.

[bullsnake]

Thanks Yetti!
I'll crawl under it this weekend and check it out. I am hoping it's something like this and not a trans. rebuild. Because of it's history with me I'm keepin' the truck no matter what, I just wasn't planning on something major right off the bat. Driving the truck for 2 1/2 hrs straight at sustained speeds of 70mph on the flat and level shouldn't kill this thing, right? I was watching the temp gage the whole time and it was always well within the 180 degree range.

What should a trans rebuild cost if that is the case? I just want to make sure I'm not gettin' hosed...

Thanks!

[phazer42]

I have had issues like this that were brake pad related... replacing the pads and no issues afterwards.....

[bullsnake]

Were your brakes pretty well worn? This truck has had new brakes 1800 mi. ago, but I have always noticed that they squeal a little the last 20-30' when I brake at a stop sign or light.

It's like this:
Put the Hummer in drive-runs like it always had.
Put the truck in reverse-runs like it always had.
Put the truck in reverse WITH the brakes applied, ie. not moving just sitting there stopped with gear selector in reverse and brakes applied=growling noise.

The trans mount seems to make a little sense to me in that if there was one that was toast putting it in reverse may cause the trans to shift under the torque load and come into contact with the frame or body, thus causing the noise. Once the brake is released torque is transferred through the driveline and growling stops.

[Yetti]

one of the other things to look at is the exhaust. if its touching the chassie it will do the same thing. if by chance you can block the drive wheels and have someone look under it while its in reverse you may have a better veiw of the noise or at least a closer area to look at when its off and you can get completely under it. DO NOT get under it with any body parts you can't afford to loose while its running. leave that for trained mechanics...(Thier expendable!)

use a pry bar to lever againest the exhaust pipe mounts and trans mount to see if they are torn. it doesn't take much effort if its torn so don't force anything if it doesn't move.

[bullsnake]

Thanks again for the heads up Yetti! I've got a freind that has a lift and I'm gonna take it over there tomorrow afternoon and see if we can figure anything out. I still have the appt. set for Monday with the dealer, but I'd just hate to send it in there if it was something simple that I could fix.

How common is it for a transmission to grenade on a bone stock '06? Is that a weak point for the vehicle? Are there any other preventative things I should be watching out or doing?

[Yetti]

Never delt with the newer ones. I left the dealer back in `95. I could only assume the later ones are still the 4L80E trans, those used to be bullit proof.