: odd knock



ReagansRollsRoyce
05-07-06, 11:29 PM
When I start the car, it does not knock. When I put it into reverse, however, a low knock occurs. It does not seem to occur from the engine, sounds more like it might be right below me. Almost sounds like it's in the car. Really doesnt do this when the car is put into D, maybe one.

I was worried about the compression/cylinders at first but I tested the acceleration and it is normal, gas mileage normal, engine smooth as silk. This noise doesn't really seem to be coming from the engine itself.

Any ideas? Motor mount? Or is it the bearing maybe and I'm in real trouble?

90Brougham350
05-08-06, 05:22 PM
The fact it really only happens when you put it in Reverse may be a good clue there might be something up with the tranny. If it were a bearing or something of that nature though, you'd know it for sure.

ReagansRollsRoyce
05-08-06, 10:25 PM
Yeah I tried to catalog everything today, but I don't know:

Shakes at idle when in Drive or Reverse (but not P) ie stopped at light with foot on service break

When pressing down on accelerator from stop, "staggers" almost to get going but then goes perfeclty smoothly, accelerates fine, no knocking or slamming from engine:
0-60 is 14 seconds which I think is the same as the original consumer reports road test back in '87 so I really doubt it's compression

knock, if I could pin point it, seems to come either from right below me or right in back of the dashboard, goes like this

release service break in D, press gas low *THUD* *stagger* *car shaky* then car goes forward normally
shift from P to R, holding down service break, low *THUD* *THUD* *THUD* repeatedly *car shakey*

any speed above, say, 5 MPH, no one would know there was a problem


tranny isn't slipping between gears (or doesnt seem to be), still maybe only the low band is going


I've never had a bearing go so I don't know what it sounds like...would it be knocking loudly at all speeds, or running really badly...

my problem comes up only in parking lots and stop lights, never on the road.



Frankly I'd be really relieved if it's the transmission, talking hundreds instead of thousands for a new engine

Probably going to take it in to someone who can fix it on Thursday, I just wanted to see if anyone had ideas since I'm going to try not to be taken for a ride ("ohhh of course you need a new engine!!!")

caddydream
05-11-06, 05:43 PM
Just a thought, the exhaust rapping against something?

ReagansRollsRoyce
05-25-06, 04:38 PM
Just a thought, the exhaust rapping against something?

And so it was! :) Thanks. The exhaust rapped. And the shake: a vaccuum hose was lose.

The compression is down some but that was unrelated, and I may have to address it soon.

johndfw
05-26-06, 09:45 AM
Hey
Check your U joints.