mike13

iTrader: (27)

OK installed the 4L80E with BMR crossmember and rubber mount, the car has a vibration thru the center console starting at 1800 gets worse at 2400 and slowly goes away at 2800rpm. Checked to make sure transmission isn't riding on the crossmember, I'm using my TCI flexplate from my 4L60 so that's not the issue.

Any idea's? Also if it where a out of balance problem would the vibration go away at 2800rpm? Wouldn't it just continue to get worse?

Any helps or suggestions would be appreciated.

mike13

iTrader: (27)

I want to add that, it's static reving, in gear, converter locked and unlocked.

Gilbert@Ace Racing

If the transmission case is touching the body anywhere you'll get some strange vibrations. Did you clearance the floor pan well? I've seen this happen in cars where guys just didn't get the body out of the way enough.

Also, is your BMR piece equipped with the torque arm mount? Or is yours a body mount set up?

I doubt very seriously that the transmission is the cause of the vibration itself.

g

Circle-D

iTrader: (21)

Does it do it in park?

Jake's Performance

iTrader: (2)

Also check for misfires.

mike13

iTrader: (27)

Yes does it in park, checked the tunnel and no touching, bmr mount does have a torque arm mount. no misfires.

Circle-D

iTrader: (21)

Disconnect converter and see if it goes away. Push the converter into the trans so it is not touching the flexplate. Only do it for a few seconds, as the converter pilot is not designed to spin in the crank. But it is a good way to test if it is the driveline doing it....

Chris

mike13

iTrader: (27)

I guess the best way I can discribe it is the vibration feels like what you would experience with a old muscle car with solid motors mounts and a th400 running down the road with 3.73's or 4.10's It's more of a buzz then a shake.

I have a built 408 with poly engine mounts, do you think just swapping to the 4L80 could cause a vibration/ buzz. I can live with it, I'm more concerned if there is a problem. It goes away above 2800rpm.

I also tried reindexing the flexplate to the converter. Also the cars a convertible with subframe connectors.

mike13

iTrader: (27)

Yes does it in park.

Vince B

iTrader: (1)

Pinion angle?

Jake's Performance

iTrader: (2)

Vince,
It happens when sitting still, so I don't think it's pinion angle. I doubt its trans related, possibly converter but its a high end billet unit that I'm sure was well balanced.

My experience with an engine or converter imbalance is that it occurs right in the 3000 rpm range and feels very high frequency.

Just had a cheapy converter a few months back that was 40 oz out in a stock truck.

mike13

iTrader: (27)

OK, I unbolted the converter and lightly pushed the converter back with a pry bar (lightly) and noticed the gap was a good .400 so I shimmed it to .200-220 bolted it back together and now it's more of a buzz vibration, much better.

Would pulling the converter that far out of the front of the transmission cause a vibration? I don't think I noticed it before because the fit was so tight and I didn't want to damage the pump.

performabuilt

iTrader: (25)

Well the fact that moving the converter caused a change tells you the area your looking at. And moving the converter further back in the pump would provide more support from the pump bushing and change the gravity center.

mike13

iTrader: (27)

I can live with it, I just want to know if there's going to be a problem? Like I said it's a buzz, if the car was built better I probably wouldn't notice it except for the plastic interior.

mike13

iTrader: (27)

OK, I think I have it fixed, I went back unbolted the converter, spun it 90 degrees slowly sucked the converter to the flexplate with just a couple of turns of the bolt at a time and then rotated 180 in a crisscross pattern. I started the car brought the rpm up past 3000rpm and it's SMOOTH. so unless the vibration moved to a higher rpm It just might be fixed.

mike13

iTrader: (27)

Had a chance to put about 20 miles on it and it works great. Thanks for everyone's help. I started a thread on this forum about how great the sponsors are, it got moved to sponsor feedback but here it it. Thanks again.

https://ls1tech.com/forums/ls1tech-s...s-section.html

LS6

Nice to hear it is solved

mike13

iTrader: (27)

Thanks