Hummer H1 knocking Noise
 

The other week I was traveling down the road and suddenly I heard a very loud crack it sounded like a spring that broke under the drivers side, and I seemed to notice more rocking when I braked.
I took it to my workshop to investigate but only found play in the ball joints,
so I replaced all the front ball joints But still noticed more rocking than usual
and when I put in drive 2 and accelerate and let gas off I notice a soft nock like play in the transmission is this normal !
I have had every wheel off the ground and found each to have the same play
checked all shockers and drive shafts seem to be OK
what could it be.

Re: Hummer H1 knocking Noise
 

Not alot to go on, but here are a few things to check:

Brake caliper brackets
Springs
Axle shafts
Axle shaft bolts, both at the diff and the one retaining the axle in the geared hubs.
u-joints
center support bearing on the front driveshaft
shocks (seen a few break at the top)

Re: Hummer H1 knocking Noise
 

I also seem to get a front brake grinding noise from the front when hot but seems to go when I brake !.

Re: Hummer H1 knocking Noise
 

You need to check your caliper bracket mounting bracket and your axle bolts. It sounds like the bolts have backed out. Major brake damage can result.

Re: Hummer H1 knocking Noise
 

I have checked the calipers I thought it must of been the cheap pads I bought at the auto store so I put some better ones in carbon metallic,
took for run and when I came back to my garage I heard what was like a brake shudder noise,
and I also have more rocking even with the slightest braking this was since I head the loud crack noise,
But is it normal to have noises when in low gear when I decelerate like transmission play but I never noticed this befor as I always have it in drive
gear.

Re: Hummer H1 knocking Noise
 

are you getting side to side rocking? if so I would check your swaybars. you could have snapped one and now its flopping around in its mounts