put in 8 3/4, now have vibration

Supershafts said

How much of the slip is in the trans ? before we just go running out and get a new shaft and then find out that slip is 9" long and you didn't need a new shaft.

You said the vibe started after going to the new gear, so you already had this entire driveline in the car with no issues.

So what was the gear ratio in the old 8.75 ?

Seems to me you may have made a big enough jump that you just need your shaft balanced

Click to expand...

I took the shaft out last night, then re-installed it. I measured/estimated that the tongue/slip engages about 2.5" of tranny spline (tailshaft?).

I know it should be more like 4.5" however I'm still not conviced this is whats causing my vibration. Maybe... but maybe not, I dont know.

The ENTIRE drivetrain was not replaced, just the driveshaft and rear end. I was already running my new 360 and a-833 without vibration for about a year... on the original 7 1/4 rear end... probly 2.94 gear.

Thanks for you help! PS - I already had the shaft balanced (and they replaced parts of it which cost me close to $200). The shop claims they shortened it according to my request (2") and tells me I'm to blame for giving wrong instructions. I wish I had given written instructions and dimensions instead of just verbal... cuz I'm convinced they screwed up and shortened it too much. Is it possible to get more length out of it? Change the slip or something?