somZ2801

iTrader: (8)

Ok In Dec. of 2013 I ordered and paid for a Midwest chassis 9 in. ,short torque arm and pst drive shaft. I had several issues with the org. build, was told 3 weeks did not receive it until late April 2014 driveshaft did not come until close to the second week of May. The driveshaft loop had to be removed in order to clear exhaust also I had to have spacers made to clear the bottom of the exhaust with the torque arm mount. I got al those issues resolved. and did not get to drive the car until 6 weeks ago when I got the issues with the engine sorted out failed piston ring landing on #7 on ls1 caused me to have to get a new engine ended up with an LS3 Finally get the money for it get it put in go to get it tuned and on the dyno the tuner says it has a really bad shake at anything above 40. So He finishes the tune and I get the car to a suspension shop to get the driveshaft pinion angle setup. This is all they do is work on high horse 8.5 to 10 sec. cars and faster. he says if it still shakes have it looked at by a driveshaft guy pull the drive shaft and bring it to them. This is where I start to get upset. they check it out and the shaft yokes are not clocked right they are off so the re clock and rebalance the shaft and had to install 2 new u joints do to the joints having some kind of copper washer above the cap to "take up clearance " between the cap and the clip. Get this all done Still have an F'n Vibration . So back under the car I go . I am looking and happen to notice that the yoke that goes on the output shaft moves up and down quite a bit. Thinking I have an issue with my trans output I pull it apart and the shaft is solid no movement. I call my Father in law and have him yank out his drive shaft and bring it over He has a 5.3, T-56 swapped Nova. I install the shaft in the trans and No movement at all It is solid feels nice and tight. So we grab the mic and measure we measure in between the splines and on his yoke with 30,000 miles on it is 1.170 mine with a little under 2000 miles measures at 1.181. (Sonnax says that this is within specs). Not sure how it moves all over the place on my output shaft there is a difference of .11 which is big and I believe has been the issue for the vibration . Boom I believe I have found the vibration its in the miss manufactured Yoke by Sonnax. So I call Midwest who I ordered the shaft through and Kevin has been doing his best to help with the running between me and Sonnax is basically been told that Sonnax has no liability for this issue and I am going to most likely have to buy a new yoke . I have included a pic of the yoke of mine next to my father in laws mine is the one on the left the black forged yoke his is the one with deep teeth . My question is has anybody else had an issue with these yokes or is it just me?

98cherrySS

iTrader: (2)

I have that same setup. Being that this is a MWC 9"/PST/Sonnax setup, the possible issues are endless. On my setup the Sonnax yoke was one of the few parts that didn't have an issue... You should also have a look at the pinion yoke at slow speeds. Mine was visibly bent and was causing a lot of vibrations. Easy to see on jack stands. My other issues included poorly setup gears (howling), incorrectly clocked AND out of balance PST driveshaft, leaking pinion seal and a crooked driver's side axle end. Axle end was toe-in 1.5° and cambered 1.2°.

Kevin97ss

My PST 3.5in aluminum with the Strange chromoly yoke had a nasty vibe, (verified with stock driveshaft). Sent it back to PST, they balanced it by drilling into the shaft and riveting washers. (pissed about that) It was slightly better but not right. Changed the slip yoke because of excess play, made no difference.

Then I swapped the T56 for a TH2004R, reset the driveline angle and had a local guy make me a new longer shaft. It was a disaster, weld yokes clocked nearly 3 degrees off and refused to correct claiming it could not cause my vibration. I stood that POS in the corner of the garage and called Mark Williams. They made me a 3.5 aluminum shaft with their chromoly yoke and Spicer 1350's a little cheaper than PST and the attention to detail was impeccable. An absolutely perfect shaft with zero vibration even going through the traps @ ~115 mph. The only thing they don't do is make it pretty and shiny in comparison with the PST shaft.

Before buying anything else though make sure your drive line angles are on the money, its simple enough but many people have a tough time implementing the theory into actuality.