Driveline Vibration

Asterix

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#41
I've heard that a lot. Why do I always have to be the first. :biglaugh:
Not to worry - you're not the first with this problem. I had a stock driveshaft out of phase for a while before I learned that it's a problem. I replaced it with a one piece shaft which removed much of my vibration at 60-70mph, but not all of it, even after rebalancing that one. Then, I bought a Shaftmaster's driveshaft which helped even more, but my vibration is still there. I'm sure my pinion bearings are the source, and need to check them this weekend (thanks IJ for how much play is allowed).

Rebuilding my diff is on my short list now, but I've not gotten the parts yet.

Asterix
 

gtsfirefighter

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#44
Looks "excessive" to me Ken!

How did it "feel"?
It didn't feel harsh or rough, just loose.

I drove to Dallas today to consult with Christian, the supra guru of DFW and he is pretty much of the opinion the diff is probably shot. He described the vibration as "droning" which is a good way to put it and felt like it was coming from the rear of the car. To add to that today while making a tight u-turn I heard a pop come from the back and it did it again turning into my driveway just now.

So we got a case of what came first? The chicken or the egg. When I pulled the original shaft off it did not look out of phase at all like I thought it did while attached to the car. But. It has eaten up two carrier bearings.
Doesn't really matter now. I've got a one piece driveshaft that is a very nice upgrade that I'll keep and I'll start looking for a good used 3.73 diff.

I'll update when I can.
 

gtsfirefighter

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#45
So I recieved my diff yesterday and swapped 'em out today. Man that's a lot of work.

Verdict: Car is fixed. It was the diff the whole time causing all the driveline vibration issues.

Now I cannot say it feels 100% but there is a significant difference for the better. No droning like before and no very harsh deceleration.

After I got the old diff out I wiggled the input shaft and there was a significant "click" about it that the other does not have. So all in all I'm pretty pleased, but am now afraid what it has in store for me next.
 

IJ.

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#46
G series Diff's have a bit of a habit of eating the Pinion bearings Ken, I've killed 2 this way myself and the genuine bearing is quite exe to replace.
 

BOOSTEDSUPRA

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#47
there are typicly 3 reasons why auto makers use a 2 piece shaft as opposed to a one piece. 1 angle whether it be pinion to tailshaft, or vertical i.e. not a straight shot from the tailshaft to the pinion. 2 length. or the 3rd a combonation of both.

as far as to "why" there is the "tube within the tube" or "rubber element" on driveshafts, it is primarily to deter vibration. a good fix but a pain in the ass to us driveshaft/machine shops that have to fix them 20 years later. :icon_bigg what happeneds is the rubber that is fitted in the tube just simply gets old and looses its ability to "stay put" in simple terms, and with us putting down some big power, it simply cannot maintain its phaze with the other tube yokes.

as far as there being a benefit going from a 2 piece to a 1 piece, depends on how you look at it and your reason for wanting one.

first thing people look at is the weight. 2 piece shafts have more parts, there for making them heavier. 2nd would be ease of maintaing a single piece. much easier to replace 2 joints rather than 3 sometimes 4 joints and a carrier bearing.

to the question "are there any set backs to going to a single piece shaft"...well, sometimes yes.

going to a single piece shaft can "sometimes" cause a harmonic resonating vibration "if" the shaft is ither built with insufficient diameter wall tubing and diameter tube. the longer the driveshaft, the more of a chance it will have to "hum" or harmonicly resonate and need to be very precise on how true or "straight" the shaft is and balanced.

one fix to this is to enlarge the diameter of the tube. another is to place a special piece of cardboard tube that is designed to go into driveshafts and help cut back on the "humm". i put these into all of my larger diameter aluminum shafts. there is also a maximum length that can be made out of steel due to the weight of a steel shaft while rotating will wanna make it "whip". and hence the introduction of aluminum shafts. but thats getting off subject, lol.

i think i babbled more than answered questions,:blah: if i can answer any questions just let me know.
 

IJ.

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#48
4 reasons ;)

The short shaft sections keep the DS speed well under critical as Japanese cars typicially use high numerical ratio Diff gears and tall overdrives in the gearboxes.
 

kunfusion

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#49
Thanks for this post IJ. I have been plagued with driveline problems for a while, and with my second differential showing signs of pinion bearing issues now. I wasn't aware of this condition, and a quick look revealed this to be a problem I have. Having talked to David via e-mail I'm looking to order a new 1piece driveshaft in the near future.
 

IJ.

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#50
Thanks for this post IJ. I have been plagued with driveline problems for a while, and with my second differential showing signs of pinion bearing issues now. I wasn't aware of this condition, and a quick look revealed this to be a problem I have. Having talked to David via e-mail I'm looking to order a new 1piece driveshaft in the near future.
Very welcome Kun!

It's something I came across about 12 years back and as these cars age it's only going to become more common.
 

Heavy D

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#53
hey guys after i read some of the post, just wonder how to see if there is play on the rear end? like spinning the shaft? i put my car up today to see whats up with my DS cause i got some vibration and low speeds and then over 80-90mph will get very bad, i did spin the drive shaft and ill give it about half inch moved and the wheels didnt spin, and when i also engage my clutch i hear some banging sounds like if my ds is trying to catch or something, im kinda starting to think its my rear end.
 

Grandavi

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#54
I am wondering if that isn't from the u-joints. I have had u-joints cause vibration on my GM vehicles and changed them out myself. Have avoided looking at the Supra system simply because they are more complex than the simple ones found on other cars.

(not sure if I am correct on this, but I thought there were more u-joints on a Supra)
 

harley1985

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#57
i have an aluminum one piece, and it gives me the same problem... Ive flopped the drive shaft both ways and get the same result... got any ideas guys?
 

toyotanos

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#58
Um, driveshafts are not 'floppable'... I'd go to a driveline specialty shop and have it checked for straightness and if it passes have it balanced.