Vibration

aerodynamic · Post by **aerodynamic** » Fri May 04, 2007 6:24 am

Hey guys,

My 400 has a fairly noticeable harmonic engine vibration. It's worse on the highway and makes driving it there really uncomfortable. Is it possible it has the wrong balancer? I seem to recall seeing liquid filled balancers available at one time, anyone know about these? I had another one of these cars years ago with a 440 and that one vibrated too. Anyone else run into this?

Thx for any help.

Greg

Post by **Eric** » Fri May 04, 2007 8:11 am

Are you sure it's from the engine? Does it make the noise when the car is not moving? In 71, Chrysler issued a TSB about transmission tunnel noise. Also, could be rear end/gear noise....my 0.02

aerodynamic · Post by **aerodynamic** » Fri May 04, 2007 12:28 pm

Yeah, it's engine. If I rev it up in park I still get the vibration. Monkeys have worked on the car throughout it's history, and I'm still in the process of backtracking through a lot of what they've done. I have no idea yet if it's even got the right balancer.

72GY9Runner · Post by **72GY9Runner** » Fri May 04, 2007 4:10 pm

Could be a possible Torque Converter issue too.

If you have a cast crank converter on a steel crank, or the other way around. Or just a bad internally damaged converter.

If you have a cast crank there should be 2 large weights on the converter. The steel crank version varies a bit. Usually no weight, or a really small one.

Something I was unaware of until I got my Runner. I had always thought that all 400's were cast crank, but there was a 400HP version in 72 that used steel. So... it pays to check closely.

aerodynamic · Post by **aerodynamic** » Fri May 04, 2007 9:19 pm

Yes, that thought had crossed my mind too. I have a rear main seal starting to leak, so maybe I'll use the opportunity to examine the converter as well. Anything's possible on this car, after all the last owner put a huge amp in the trunk but neglected to fuse the power feed wire, which melted itself to the underside of the old carpet and fried quite a few wires under the dash. He also filled the A-pillar rust holes under the vinyl with plumbing foam. This car deserved better (and got it, thankfully).

71440 gtx · Post by **71440 gtx** » Sat May 05, 2007 2:15 am

72 74 400 4bbl 4speed are steel crank

72 -74 400 atuo are cast crank

72GY9Runner · Post by **72GY9Runner** » Sun May 06, 2007 1:16 pm

Are we sure only 4 speeds got the steel crank?

The friend who sold me my Runner has a yellow factory auto with 400 and the air grabber and it was a steel crank car as well. Anyone else know of steel crank auto cars?

Mine is one now.

71440 gtx · Post by **71440 gtx** » Sun May 06, 2007 2:14 pm

Shown above is damper #3614374, used on 400's with external balance cast cranks, /or automatic trans application 400 4bbl or 2 bbl(applications with 400 engines manual transmission applications used forged cranks.) I

3614371 72-75 std forged