Help diagnosing periodic knocking and driveline jacking while stopped in gear

[pursuit]

I'm thinking I've got a broken mount somewhere but can't find it.

Intermittent symptoms:

When at a stop, foot kept on brakes and in gear, I sometimes get a knocking sound that seems to be coming from the driver's side near my feet. I have an exhaust leak at my outside y-pipe to downpipe flange that could be related to a flexing (?) or could be unrelated. If I put the truck in neutral, foot kept on brakes, the knocking sound stops.

I don't see any movement in the trans or tc levers.

If I keep the transmission in neutral, and let off the brakes, there's a pretty significant unloading of the suspension towards the driver's side. Like the driveline is torquing towards the passenger's side and the brakes are holding it in that position until released, it settles maybe an inch on the driver's side.

Any thoughts? It's my 91 on J springs.

 

[grizzlygibbs]

Have you gotten under there yet so try and see what's going on with anything or if things do not look right?

 

[pursuit]

I don't see any bad mounts, although I forgot to mention the passenger side swaybar bushing is pretty bad. The exhaust downpipe I mentioned that is leaking doesn't seem to have any marks on it nor does the frame where it crosses over.

 

[pursuit]

Thought I'd follow up on this, it was the front swaybar. A combination of a bad bushing at the bar and loose mount lift extensions had been allowing almost an inch of shifting.