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Discussion Starter #1
Car: A new 4l80e, single mkiv supra, new PI 5 disk lockup, solid driveshaft

Issue: Vibration under load. Approximately anything over vacume vibration occurs whether from a roll on or right upon taking off. Car however will cruise at light throttle smoothly. Will cruise at 85mph as smooth as can be also. Car did vibrate a bit while revving the car in Park 2000+rpms with a different crossmember. But the skinnier crossmember doesn't vibrate while doing free rev's. Crossmembers mind you hold the transmission at the same spot.

Failed attempts to fix:
-Solid drive shaft has new Ujoints and just rebalanced as it was shortened as i went from th400-4l80e
-Moved spacers up so transmission sits higher for a more ideal pinion angle.
currently Transmission 0 degrees, rear end sits 0 degrees, driveline -2 pointing down from engine. But it was a oil changing jiffy lube shop who measured it so who knows how accurate that is.
-Hammering out around the transmission and trying to insure 1/4 inch clearance.
-Utilizing rubber mounts for transmission crossmember
-Using a vacume tube hose and looping it over the transmission and slowly pulling it down and seeing if it catches. It's at 1/4 inch clearance in 2 spots. Does the body and engine move in a fashion to move 1/4 inch closer to each other?
 

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drive shaft out of balance ??
 

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Discussion Starter #3
Okay. Diagnosed the vehicle more.

Noticed the vibration was easily noted by placing a metal bar on the exhaust and feeling it vibrate though.

So we disconnected the torque converter vibration still occured, lifted the engine vibration still occured. So its' either the engine (highly unlikely for a straight 6), or the flexplate is out of balance despite it being brand new.
 

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A lil off topic, but my Ford AOD does the same thing. I just thought it was the drive shaft being out of balance or because it's a one piece drive shaft. Do torque converters need to be balanced? That's what it feels like, but she does vibrate while cruising and when I rev her.
 

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Discussion Starter #6
Well still no solution...
The issue remains


ISSue: 1300-3800rpm vibration upon any load other than very light throttle or maintining speed. Vibration also occurs while car is in park revving it. Idle is fine.

It can't be the driveline the car isn't moving when the vibration is occuring in park.

Since then i've pounded out the car even more for extra clearance.
I've balanced the AFT billet flexplate which was off 4 1/2 grams and 2 1/2 grams on the other side. Sent hte torque converter in to PI which they didn't seem to notice anything but i don't think they sounded confident when i asked if they inspected it.
 

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Well still no solution...
The issue remains


ISSue: 1300-3800rpm vibration upon any load other than very light throttle or maintining speed. Vibration also occurs while car is in park revving it. Idle is fine.

It can't be the driveline the car isn't moving when the vibration is occuring in park.

Since then i've pounded out the car even more for extra clearance.
I've balanced the AFT billet flexplate which was off 4 1/2 grams and 2 1/2 grams on the other side. Sent hte torque converter in to PI which they didn't seem to notice anything but i don't think they sounded confident when i asked if they inspected it.
Same issue I have, if any one has any input then it would be appreciated.
 

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Discussion Starter #8
-Solid drive shaft has new Ujoints and just rebalanced as it was shortened as i went from th400-4l80e
-Moved spacers up so transmission sits higher for a more ideal pinion angle.
currently Transmission 0 degrees, rear end sits 0 degrees, driveline -2 pointing down from engine. But it was a oil changing jiffy lube shop who measured it so who knows how accurate that is.
-Hammering out around the transmission and trying to insure 1/4 inch clearance.
-Utilizing rubber mounts for transmission crossmember
-Using a vacume tube hose and looping it over the transmission and slowly pulling it down and seeing if it catches. It's at 1/4 inch clearance in 2 spots. Does the body and engine move in a fashion to move 1/4 inch closer to each other?
Hmm let me add to the list of attempts

-New stock motor mounts
-Balanced flexplate
-Sent the torque converter in
-Pounded more and the transmission has clearance all over hteplace
-Adjusted the exhuast for more clearance not that it was touching
-Adjusted a intercooler pipe which was touching the body
-Pinion angle is within 1/2 degree


This is a nightmare. I've spent $600 already on diagnosing this problem with still no luck. Not including the labor. I must regret doing a 4l80e swap.

Looks like it's either teh transmission mount which visually looks fine. Or something is unbalanced inside the transmission.
 

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Enter The Supra
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My 4l80e causes 0 vibration in my car. Although I think you went with the stock gm bellhousing? I wouldn't roll out the PI converter unless you definitely know they looked at it, I've had issues with those guys in the past.
 

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Discussion Starter #12
I essentially got a fix. Switched out the transmission mount which was a tougher rubber to a older squish rubber one my transmission builder had left over. The vibration is essentially gone.
 

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Blood for Blood
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Great to hear...


what mount do you guys use with the 4L80E?

another question I have is what does just a 4L80E run price wise? like if I can find one that is... I cant afford the 7500 kit that SP has...
 

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Discussion Starter #14
Great to hear...


what mount do you guys use with the 4L80E?

another question I have is what does just a 4L80E run price wise? like if I can find one that is... I cant afford the 7500 kit that SP has...
I'd budget $5500+ not including labor or the driveshaft.
so you can do it cheaper than the SP kit.
 

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breakem, Ive been told(and done it) countless times that flex is a bad thing, and by adding more flex you made it even worse. You should not be moving enough to have issues with poly type trans mount. Although the symptoms may be hidden, I think you still have issues. The hidden issues could end up being catastraphic if un-fixed.
Have you checked the rear bushing(the one in the tail shaft housing that centers the output shaft)? I had a vibration and that ended up being the cause, the bushing had slipped forward letting the output shaft slightly wabble(wasnt visable with eye though)

Hope you dont take the first part of my post as an insult or critisizm, just the fact that a few now are running this same trans(although the trans type really doesnt matter IMO) with a poly type mount and no issues, you still have issues elsewhere. Figure up your own pinion angle to verify its done correctly too If I were you
 
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