Driveline Vibration

[IJ.]

Car harsh on acceleration or deceleration?

Most people point to the Centre Bearing as the culprit but even a badly worn/floppy one is seldom the cause.

Check that the Rear Bonded tube in a tube hasn't slipped out of phase, just sight along the Uni joints they should all be perfectly in line.
(common failure with these cars)

A good "fix" for this issue is to take the shaft to a DS shop and have them replace the bonded rear section with a tube making the DS a true 2 piece.

(thanks to Gaboon for the pic)

 

[gaboonviper85]

Both ujoints should be centered in the "GREEN" line....the redline is showing how far out of phase the rear bonded tube slipped!

This caused my car to shake really bad at 40+mph....not only that but it wiped out the transmission tail housing bearing "bearing that the outside of the driveshaft yoke slips into behind the oil seal"....this also destroyed my centre support bearing!

This was in an 87 na...but also goes for gte cars as they use the same rear halves...

 

[paradox616]

interesting! ill have to check mine, whats a common cause for clunking in the driveline? (i've fitted a new centre bearing as it was worn)

 

[IJ.]

Backlash in the Diff will cause a clunk.

 

[paradox616]

Backlash in the Diff will cause a clunk.

yeah that's what i thought my car was a single pegger then had a lsd fitted so i'm betting they skipped checking the lash and just reused the shims. uni joins wouldn't cause a clunk would they?

 

[gaboonviper85]

They can but if they are clunking you'd sure as shit know it! They make all sorts of noise when they fail!

 

[paradox616]

They can but if they are clunking you'd sure as shit know it! They make all sorts of noise when they fail!

i doubt its the uni's then, its more of a clunk when for example your in second decelerating (engine is putting resistance on the drive-line) then you apply throttle and begin to accelerate and then resistance shifts and the drive-line puts resistance on the motor. (if that makes sense)

 

[IJ.]

Check the lash on the Diff input.

 

[gtsfirefighter]

Ok. So today I finally had the chance to get up under my car. The first pic is looking straight up at the u-joint just behind the center bearing. Sorry, but it's a cellphone pic with me under the car and very little clearance. I did have the car in neutral and rotated the shaft so that that knuckle in the pic would be straight up and down.

Here is a pic looking down at the last u-joint. Notice how it's offset some. Does this mean my shaft is out of phase? If so could this have caused my first center bearing to fail? After replacing it, the center bearing, last week I noticed the vibration was worse.

 

[IJ.]

If it's out of phase Yes and Yes, it will be more noticable either on power ore backoff, most times it's harsh on overrun when you lift off the throttle and let it engine brake.

 

[gtsfirefighter]

If it's out of phase Yes and Yes, it will be more noticable either on power ore backoff, most times it's harsh on overrun when you lift off the throttle and let it engine brake.

So would you say from looking at those pics, it's out of phase?

My acceleration feels very "course" and when decelerating like on the freeway it feels like I'm driving over very fine bumps, more of a loud buzzing feel.

 

[IJ.]

So would you say from looking at those pics, it's out of phase?

My acceleration feels very "course" and when decelerating like on the freeway it feels like I'm driving over very fine bumps, more of a loud buzzing feel.

ie: "Harsh"

Need a pic along the shaft to be 100% sure but it's easily visible to the eye when they're out of phase so you tell us

The Uni's should be perfectly in line!

o---------------o

 

[gtsfirefighter]

ie: "Harsh"

Need a pic along the shaft to be 100% sure but it's easily visible to the eye when they're out of phase so you tell us

The Uni's should be perfectly in line!

o---------------o

Well I couldn't get a pic of the whole back half of the shaft from under the car, but I'm going to assume that it is because with the front straight up and down, the back is cocked off to one side. So the search for a remedy begins before I destroy this newer bearing. Money will be the issue, especially while going through a divorce.

 

[IJ.]

You have a couple of options, find a straight shaft and install it along with a balance or have the bonded section replaced with a straight tube making it a true 2 piece (this is what I've done in the past)

 

[gtsfirefighter]

So one more question. If I take a good stock rear section and just bolt it up without taking the whole shaft in for a balance will it for sure vibrate or will it just be a crapshoot and I could get lucky and it won't?

 

[gaboonviper85]

It's a crap shoot....bad news bears!

Our shafts spin pretty damn fast...I wouldn't fuck around with a balance!

 

[mecevans]

i usually have a ton of vibration anything over 25mph. its really fucking annoying. today i was backing out of a lot and i gunned it in reverse to get on the other side of the road. i now have NO vibration!kind of a ghetto fix but i been driving it all day and its smooooth!

 

[gtsfirefighter]

Well I replaced the rear section with a used piece and had success...for a little while then it all started again and got worse! I ordered a transmission mount and replaced my old oil soaked one and that in itself made a huge difference in the way the car felt cruising down the highway. It raised the rear of the tranny up over an inch but I still have the harshness on decel and accel. So...An entire new DS is on it's way from Shaftmasters. If that don't fix the issues then I don't know what I'm going to do 'cause I fear it may be diff or tranny related. But everytime I've replaced something driveshaft related, it made a difference, so who knows. Taking off from a stop I still have the grinding feel every now and then that feels like it's coming from the rear of the vehicle. The supra is my daily now but sometimes I think an SC 400 would look good in my driveway.

 

[gaboonviper85]

A trans won't cause ungodly vibrations no matter what's wrong...it's either broke without question or smooth as ever!

Did you have the ds balanced after you replaced the rear section?

 

[airhead04]

I get a vibration from the rear of my car, but only in 1st gear between 2000-3000rpms. And it squeaks when I slow down, Idk what it is. Could it be the driveshaft or is it the diff???:1zhelp: