vibration at high speed

[jbirdcamaro]

I have a 68 Camaro with ls6 and t56...4.11 gears,,, I started this build with a 8.5 rear end.. I had a vibration and when I found the rear end bad, I changed it out with a 9" and had a new drive shaft made as well because it had to be 2" longer,, got done and went to drive and I still have a vibration... when I had the drive shaft made I seen there was no weights on the tube for balancing, so I asked the builder if it was balanced and he said yes it was..(he said it didn't need any ) so I put it in,,, it still vibrated,, so I called strange and bought one of there shafts,, put it in ,, and it still vibrates,, but it starts to vibrate at 80 and up, but when I had the shaft with no weights, it would start to vibrate at about 135., but I still have the strange drive shaft in it... a friend of mine has another t56, so I put it in to see if it was the transmission,,, and hell , the vibration got worse with his tranny,,, so I am lost, don't know what to do... has new rear end,, new gears .,, new posi unit,, new bearings,,,new third member ,, new axles,, new drive shaft ,, new yoke can any body give some ideas...... thanks

[Mach Par]

Checked the pinion and transmission angle?

[minendrews68]

Checked the pinion and transmission angle?


X2, I'd be willing to bet your problem lies here. There is a lot of information on this site about the drive train angles. You can do a search and find more than enough reading. I too had a thread about it.

[IMPALA MAN]

When putting a T56 in, you will usually find that the drive line angle ends up in the 5 - 5.5 degree range when you push teh tranny up as high as you can in the trans tunnel. Not good. Hence why Speedtech came out with......... http://www.speedtechperformance.com/index.cfm/page/ptype=product/product_id=264/category_id=30/mode=prod/prd264.htm

[jbirdcamaro]

when I had the lt1 in it I had a t56 in it as well and it did not vibrate,,, but maybe this ls6 sets a little higher and wont allow me get the angle I need, it is at 4degrees down right now and I have the rear end at 2 degrees down now,,, thanks for the info I will go make them changes now.

[jbirdcamaro]

i found the problem,,, even though i had a brand new billet transmission yoke, the inside splines were to big,,, i talked to strange and they told me that they make a yoke just for the t56 because for some reason the splines are a little smaller them the 700. 350. glide, 4l60e ect. so they make ayoke for it... i found it by taking a stock drive shaft out of a stock camaro with t56 and taking the yoke off and putting it on my drive shaft and the vibration is gone, the reason i am getting one from strange is because i want the 1350 ujoint,,,, the stock is a 1310
thanks for help

[jlcustomz]

Hmmmmmm, been dealing with vibration problems for years, which is getting worse recently & could be 1983 steel driveshaft or possibly pinion bearings starting to go bad. I did however notice that the th350 yoke could be a little tighter.

I'm getting a constant rumbling sound, kinda like a stereo bass test signal.