4L80 Swap Vibration
12-27-2009, 09:56 PM
#1
4L80 Swap Vibration Okay guys here is the issue that I am having. I have done the 4L60-->4L80 swap and I am getting a vibration pretty bad
. I am using a Yank crossmember and a UMI adjustable torque arm. I shimmed the stock trans mount and adjusted the driveline/pinion angle to -2 and was still getting a bad vibration at about 60+mph
. So today I wanted to try and narrow down what it could be. So I started off with taking off my driveshaft to see if it was that or the pinion and sure nuff I was still getting the vibration in all the gears at about 3000rpms
. I have been told that it could be 1 of 2 things, the harmonic balancer or the torque converter. Do you guys have any idea on what I should check?
. I am using a Yank crossmember and a UMI adjustable torque arm. I shimmed the stock trans mount and adjusted the driveline/pinion angle to -2 and was still getting a bad vibration at about 60+mph. So today I wanted to try and narrow down what it could be. So I started off with taking off my driveshaft to see if it was that or the pinion and sure nuff I was still getting the vibration in all the gears at about 3000rpms. I have been told that it could be 1 of 2 things, the harmonic balancer or the torque converter. Do you guys have any idea on what I should check? 
12-28-2009, 12:40 PM
#2
okay so to update I got the mechanics under the car and they had me revv the engine in N to about where I feel the vibration and it was still there so they knew it was torque converter related. So they disconnected the converter from the engine and tried it again. Low and behold no vibration. So they tried to mount it with the other 3 mounting bolts, still there and then tried other combinations (rotating it to different mounting positions) and still vibration. Whelp now I have to wait for Yank to open back up on Monday so we can get it in there to fix it. It was a good thing I was finally able to get on the highway to try and get pass the break-in mileage or I would have never known about the vibration.
01-05-2010, 09:39 PM
#3
Okay now it may not be the torque converter. I was told that it definitely sounds like something is vibrating on the body of the car be it the transmission or the exhaust. And to my great luck he said that it isn't just one thing but two vibrations going on. The second being from the driveline. Something there is off so I am going to have to mess around with the yokes and u-joints to get this figured out. The driveshaft still has its weight attached and a couple of scuffs that have been there for a while but nothing new. So the plan is going to try to find something that is rubbing or touch something connected to the body. Oh and how we found out it wasn't the torque converter was there wasn't the vibration that started a differnt rpms and stopped and when we were moving and the vibration kicked in we put it in neutral and it was still there so that is what pointed us to the driveline. So tomorrow will be a day of trial and error
01-05-2010, 09:57 PM
#4
okay so someone help me with this though, if you are looking at the engine from the passenger side meaning you would be standing right next to the passenger front wheel and looking at a angle finder it would tilt to the right towards the front of the car and read 3* measured at where the starter would be, the driveshaft is a 0* measured about a foot or so from the pinion yoke and the pinion is at -2.5* measured at the bottom of the torque arm. Is there anything wrong with this????
01-05-2010, 11:30 PM
#7
If you are measuring where the starter bolts, you are getting the trasmission angle.
I would need to see the car but there are a few basic rules to setting driveline angles.
One is that the centerline of the trans output and rear pinion cannot be in a straight line.
If the trans was at 0*, driveshaft at 0*, and rear diff at 0*, it will vibrate, usually very bad.
If the trans is down at the rear 3* (pretty normal angle), the driveshaft is also going downward at what is called the working angle, and the rear pinion is at say 0*, you would be OK.
The pinion angle will also come up slightly under acceleration load, so the downward angle you have now is probably not an issue.
I'm not that familiar with the 4th Gen's.
Some cars have the rear diff higher in the chassis than the trans centerline, in this case your working angle of the driveshaft would be a positive number.
Just from your post, I don't like the 0* driveline angle.
I would need to see the car but there are a few basic rules to setting driveline angles.
One is that the centerline of the trans output and rear pinion cannot be in a straight line.
If the trans was at 0*, driveshaft at 0*, and rear diff at 0*, it will vibrate, usually very bad.
If the trans is down at the rear 3* (pretty normal angle), the driveshaft is also going downward at what is called the working angle, and the rear pinion is at say 0*, you would be OK.
The pinion angle will also come up slightly under acceleration load, so the downward angle you have now is probably not an issue.
I'm not that familiar with the 4th Gen's.
Some cars have the rear diff higher in the chassis than the trans centerline, in this case your working angle of the driveshaft would be a positive number.
Just from your post, I don't like the 0* driveline angle.
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01-07-2010, 06:58 PM
#9
okay so get this, the problem and everything wasn't anything but the yoke and the u-joint. The clips for the yoke came off and the u-joint was beat up shot and almost killed. All issues are gone now except that the place I had my car may have re-flashed the pcm so now I am getting codes P0740 (Torque converter clutch solenoid circuit/open) and P0785 (Shift/timing solenoid). I just had it tuned for the 4L80 now I am wondering if the reflash put it back to the 4L60? Has anyone had any experience with this one?????
P0740 (Torque converter clutch solenoid circuit/open) and P0785 (Shift/timing solenoid). I just had it tuned for the 4L80 now I am wondering if the reflash put it back to the 4L60? Has anyone had any experience with this one????? 