Well I dunno what gives. The trans is new, but it did this with my old 700 as well. I replaced the tranny mount and torque arm mount with energy suspension pieces. But say I take off, 1st-2nd is usually nice and smooth, 2nd-3rd has a little clunk, but say the car is just about to shift to 3rd and I start slowing to a stop, she clunks hella bad, like you can feel it crazy style, almost like its letting off a huge amount of energy. But I don't understand why. Could this be something with the kickdown cable? I dunno what else it would be. The trans itself prolly has like less than 10k miles on it, its a pro-built street/strip model and I am running a 9.5" vigilante. But like I said, the car did this with my old rebuilt GM tranny, still does it with the new combo. What could it be? Also the car has fresh poly motor mounts, so its not that..... I'm stuck here fellas, ANY INPUT???

Will

 

Have you checked the U-joints?

 

Sorry, Everything, and I mean EVERYTHING from the flywheel back has less than 10k miles on it. Including the freshly balanced driveshaft with new u-joints.

Will

 

Mine made the same noise - the clunks were so loud I got worried and headed strait home.

To fix it I tightened up the diff. pinion nut and decreased the backlash a little bit (from 0.012" to 0.080"). The clunk totally went away after that.

If you are going to tighten the pinion nut you should check the preload at least by hand with the carrier out so you know where you are at. I set my pinion preload up last night with a in.-lbs. torque wrench to 14in-lbs. That is tight enough where, if you spin the yoke, it should stop immediately.

 

how do i do this. i have a bw rear end, cn you guide me through it? it is really annoying, sounds like the trans is gonna come through the floor

Will