Hi, got a quick question: I need to get my driveshaft balanced, have some vibrations that didn`t disappear after some checks and changes(tires, wheels ect). I got some ramps, about 10 inches high I can roll the car on. After that I was told it`s just loosening the 4 screws at the diff. and I can take it out. My question: will any fluid leak from the diff when I remove the driveshaft? The tranny is no prob, with the back of the car up it`s angle shoud keep it from leaking, but it`s just that very angle that could give me a good shower if I`m under the car. Any opinions? Jens
Didn't you just swap in a 200-4R? You might want to check your pinion angle before you have the driveshaft balanced. When I did the 200-4R swap I had insert a 1+" spacer under the transmission mount to correct the pinion angle. Since you're pulling the driveshaft go ahead and get an angle finder and measure the angle on both the transmission and rear.
Hey Bill, jep, the swap was done about 2 weeks ago, and I had my first ride last weekend. The vibrations did exist before, they somehow suddenly appeared last summer, didn`t notice them before. After the transmission and rearend swap they come in a little sooner, like between 50 and 60mph, used to be 65-75mph. And a second time between 75-85mph, I`m really afraid I`m going to shake the whole car loose. Otherwise it`s dead silent. I tried new tires on new wheels, no change, a friend of mine who`s a mechanic told me the bushings seem to be ok, and said I should check the driveshaft. Vibration comes also in "neutral". So, good to know nothing will happen in the back when I pull the shaft, thanks. Jens
You say it does it in neutral? HUM well it has to be some thing rolling then... Like a tire (I know you checked them) And you say after the rear swap it comes in sooner...so it is rpm induced. You say you had it before the rear and tranny swap. How about MOTOR MOUNTS? OR shocks on the rear??? TRY those too. Inspect and see how fast the shock slides in and out Some shocks LOOK fine but are blown out on the inside Motor mount you will need a pry bar...A lift would be nice here. JIm
Sounds a lot like the problems I had with mine and you will find it extremely hard to believe what it ended up being. http://www.v8buick.com/showthread.php?t=202378&highlight=driveline+vibration
Bill, this sure sounds interesting...and believe me, I think I know what you went through....damn it`s so annoying. But unfortunatly I swapped the converter with the transmission as well, so it would have to be a failure in the old and the new one...I don`t think so. But luckily yours went away, hope to get over with it just the same soon. Jim, thanks for the rear gears, they`re silent and work fine. I`ll definitly check on those areas you mentioned. You said "rolling", isn`t the driveshaft moving, even though in neural, at any given speed? It could cause it, couldn`t it? Damn, if it`s not the usual suspects like wheels it gets way over my head.... Thanks for your thoughts and ideas Jens
YES, it is always moving BUT when you throw it into neutral load is removed from the driveline and will most likely make a change in the noise...Does it?
In my case, no, it didn't, which is why when the transmission guy told me it could be the converter I just looked at him and thought "no way", and I was certain that dropping the transmssion that day to change the converter was a complete waste of time, but it wasn't.
Balancing is cheap and easy to do, might as well have them put solid u joints in there while it's apart, but I would recommend the pinion angle check as well, my buick was bad after my swap, I had to make rear adjustable control arms to bring up angle... And it made a huge difference...
I think balancing won`t be too much a waste of money, even if I don`t get it, chances are it might be just that, right? But Jim, no change of sounds when I go into neutral. And now something from far far away: I was going up a hill while cruising and had the impression that this calmed her down a bit. Also had less vibration with some load in the trunk....not so much, but it seemed to be less.... Damn Jens
Pinion angle ... As the chassis goes down in the back the engine and trans will also slightly point down towards the back and then adding more grade to the driving increases the torque to the drive line again CHANGING THE PINION ANGLE. I would shoot for the pinion angle being the problem which will also concur with th e rtatio change and rpm change... ALL points in that direction. YOu can use washers under the trans mount to play with the pinion angle or adjustable upper control arms for the pinion angle in the rear to be adjustable. I would start cheap with the trans angle JUST to see if it gets worse or better OR moves again in the RPM range. Jim
make sure the yoke is slid into the tailshaft bushing far enought too. too short of a drive shaft can make these problems. also, once you unhook the drive shaft the car will want to roll ... make sure you have the wheels chalked/parking brake set/or even batter have the axle housing on jackstands instead of using ramps. we only get one chance to die.
I agree with this also too short a drive shaft will make a sloppy output of power and cause a vibration. any more that 3/4" -1" and that is TOO much slide out...You want as much on the output shaft as you can get with out binding .
Lots of good infos coming in from you guys, I wouldn`t know how to handle my car without you, just to let you know! Ok, so I`ll get to the shaft in a week when my wife and kid are not at home and I can go for it all night. I`ll check on the angle BUT: I had vibrations BEFORE the change of trans and rear gear, and it wasn`t even touched then. I have a rather sloppy original 350 in my car, everthing is, or was, original, the car had been standing for 10 years, I resurrected it in 2009 and drove it for about 1.5 years and about 6000 miles. The vibrations just stared someday, and I didn`t do anything to it except a burnout once a while. Since it`s not too much of a torque monster with it`s smog 350 and a (then) bad Quadrajet, I don`t know what might have been the problem, and I don`t see how I could have changed that angle or bent anything. The slip yoke question: I swapped the TH350 to a TH2004R from CK, so shaft lengh ect should be the same. Why should the yoke be not deep enough in ? Jens
food for thought ... if you are sitting still (basically) but you are doing a (single tire) burnout with a non-posi rearend and the speedo says 100kph .... the spinning tire is spinning 200kph:3gears: and the spiders in the rearend are working really hard. :Smarty:
EXTREMELY HARD!!!! lol. !!!!! 3-4 times as fast as the ring and pinion.... this is why they melt to the center cross shaft pin they ride on...lol. JIM
A lot of things can change the pinion angle your rubber bushings in the rear end control arms could have ripped and or collapsed. trans mount could have collapsed sagging springs ...
if the trannys are the same length and you didnt have significant wear on the yoke, that might be all ok.
Ok, I`ll check on all the points you guys mentioned and let you know if it changed, and if so, what I did to change it. Thanks for your help Jens
