cannonball55 Posted April 20, 2010 Share Posted April 20, 2010 73' 240z with LS3 swap done with a John's cars kit, rearend is r200, and new urethane bushings everywhere, had a 700r4 and driveshaft had about 5/8" of play. Was just enough to be able to remove it from the rearend flange. I recently swapped in a T56 and its about a half inch longer than the 700r4 was. The yolk was the same splined so I slid it in and put everything back together, but now when bolt are out of the driveshaft at the rearend I only have about 1/8" of play. To remove the driveshaft I have to drop the trans mount which dips the rear of the trans to get enough room to remove it. That part is fine by me, I don't plan on removing it often anyways. The question I have is gonna be any binding issues? Everything is supposed to stay pretty much where it is with an independant rear but I know everything is rubber mounted. The way I figure is under load the rear diff is going to try to lift (opening the gap larger) which wouldn't be an issue, but not sure about braking or cornering. I have no unusual pops or grinding but figured I better ask before some appear or if its not a problem at all and I'm worrying over nothing. Thanks Stewart, Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted April 20, 2010 Administrators Share Posted April 20, 2010 It is likely to cause you trouble. The problem is, the engine/trans will move rearward and slam into the yoke, especially as you transition from hard braking to hard acceleration. The least that can happen is seal failure. A good friend did something similar with an S130. He cracked two tailshaft housings before figuring it out. I shoot for 1/2", but I suspect most people could get away with 3/8". Anything less than that (with rubber mounts) would have me uneasy. Quote Link to comment Share on other sites More sharing options...
cannonball55 Posted April 22, 2010 Author Share Posted April 22, 2010 Problems.... 20 miles after swapping in the t56 the rearend started howling at about 45-50 mph and got louder the faster I went. It only howls under load and goes silent as soon as I let off the gas. Last night I pulled the driveshaft and took it today to have it shortened by 3/4 of an inch. I drained the gear oil out of the rear to make sure it wasn't eating itself. There was no metal on the magnet and oil came out looking like it is supposed to. Do you guys think it was just from the shaft being too long or that there is something else going on? Never had any noise come out of the rearend before. Never seen one just howl under load like that. Normally they start growling when a bearing is failing or howling when the ring gear is shimmed wrong or the pinion crush sleeve is incorrect. Anyone seen anything like this? I figure if it was a bearing or gears failing the magnet would look like a pom-pom with metal shavings (I had to drive car 80+ miles with it howling like that). Any help would be much appreciated. Trying to get everything back together by friday, as I plan on breaking into the 10's this weekend at the dragstrip Thanks, Stewart Quote Link to comment Share on other sites More sharing options...
ezzzzzzz Posted April 22, 2010 Share Posted April 22, 2010 It doesn't sound good to me. The driveshaft definately needs to be shortened though. "Trying to get everything back together by friday, as I plan on breaking into the 10's this weekend at the dragstrip." From your description it sounds like you just might be breaking something this weekend even if it's not a 10 second run. Quote Link to comment Share on other sites More sharing options...
cannonball55 Posted April 23, 2010 Author Share Posted April 23, 2010 Got the shortened driveshaft installed and put new gear oil and limited slip additive added. Still howling but only under load from ~45mph and up. Gonna start new thread for just the rearend noise instead of the driveshaft question. Thanks Stewart Quote Link to comment Share on other sites More sharing options...
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