vibration under load yoke related?
11-12-2013, 11:54 PM
#1
vibration under load yoke related? I seem to have developed a vibration that only comes when I'm under moderate acceleration. I can't see if it gets any worse if I really give er the onion because I'm still on a break in tune and I can't get into any boost. I notice it driving around town. It is more prevalent once the trans shifts into second gear. On the high way it is definitely there at interstate speeds. It almost feels like the driveline vibration that the old lt1 cars had at speeds above 100+ (on a track of course lol). I am trying to get the car ready for a dyno session this weekend so I'm trying to pin point this vibration problem before I go since I have to haul the car 300 miles to get it tuned! I was curious about yoke lengths on 4l80e's. How far can the yoke be from the tailshaft before you have spline engagement problems. It seems like the yoke has to pulled quite a ways out to get hooked up to the u joint. I haven't verified how close it is once the car is sitting on the ground simply because the dang thing is so low to the ground. I was wondering it this might be an issue. Not sure where to really post this since I doubt it's rear end related due to the fact it was in the car before the 4l80e swap. Thanks for the help in advance. Chris
11-13-2013, 07:40 AM
#3
No I have a chromoly that came with the Dana s60. I got to thinking about it last night after I posted. The car is lowered and I did correct for driveline bind previously (spohn torque arm) the car sits lower now due to all the extra weight from all the turbos stuff 4l80 etc. I know at the bare minimum I have to realign the rear end with the panhard since the rear is shifted to one side due to the ride height change. It would make sense to have vibration under load. No vibes on decel or coasting or even light throttle. Just under load.
11-20-2013, 01:25 PM
#5
I have a chromoly drive shaft that I got with the s60. It worked fine with the t56 before the 4l80 swap and from my understanding it's longer than the t56 so idk what the deal is. Took the yoke out today and it measures 5 1/2 from end of yoke to center of ujoint. Tail shaft seal is bad. With the yoke in it has a small amount of play ( probably 1/16-1/8") with the yoke out it has probably 3/16-1/4" play. I was wondering about getting a longer yoke to get a little more spline engagement on the splines. I know that'll still put the u joint at the same distance away from the tail shaft housing but I don't really want to buy another new drive shaft. I don't know if the bushing is bad or not. The yoke shows no signs of wear. Does that end play sound normal? No poly mount btw.
11-20-2013, 07:32 PM
#6
You might be having the same problem that I am having. Under heavy to moderate load or a WOT 1-2 shift, I get a rapid thumping sound from under the car. At first I thought it was the driveshaft hitting the tunnel, as it's pretty close. I also thought it was the yoke, but there's a lot of play in the output shaft regardless of whether the yoke is on or off. The problem was pretty clear when I got the driveshaft off. I ordered the rebuild parts and I am going to have a buddy tear it apart and fix whatever is broken.
BTW, I don't think there's a bushing in my tail housing - just a seal. I think the output shaft gets all of its support from two bushings inside the case but I'm not 100% sure.
BTW, I don't think there's a bushing in my tail housing - just a seal. I think the output shaft gets all of its support from two bushings inside the case but I'm not 100% sure.
