Drive Shaft from Power Train Industries

[juiceman]

OK My vibration is got to go

I looked at some Z sites and they recommend the products from Powertrain industries.

They offer a two piece shaft with a u-joint instead of a band joint at the transmission. The cost is $231 delivered vs ~550 from scotsdale and 650 locally

The u-joints on their unti are replaceable and it comes with a new center bearing and mount

The center bearing alone from scottsdale is close to 110 but I do not think I can do myself because of pressing the bearing

I could do the drive shaft myself

So my dilema, spend 2 times the amount and get a whole new shaft or half and get just the bearing and pray it solves my problem

MAn, I wish I had the experience of year of repairs on these cars to aid me. I guess that is where this site comes into play

BTW the vibration is not really in the mid of the car, more of the front mid.

Thanks for any help

[VimyJ]

You were going to have the U joints checked. Any news? That drive shaft deal sounds good.

[juiceman]

Monday Morning my local mechanic is lending me his lift to check them out

If they look like they are ok but just ok I willprobably go the drive shaft route but which one I am not sure.

The One side says go for it, the Q45tech side says do the factory unit

Man I am so confused. Sometimes too much info is not good

Will keep y'all informed

[texasoil]

Have you replaced the rear transmission mount? If it has sagged, it will cause all osrts of vibration that can be mistaken for driveshaft. Unfortunately, 'visual/finger feel' inspection will not reveal the sagging. If you have not replaced it in the last 4 years, try it.

Next try 'hitting' on the U-joint yokes at each cross to 'shake up' the needle bearings. They will often get stiff and 'notchy' and will cause vibration. You may want to remove the rear joint from the diff yoke to flex it a lot further than normal to ensure it's smooth. The 'hit it with a hammer' works like a miracle if that is the problem. The U-joints do not wear out.

Sometimes the elastomer sleeve that is bonded to the inner and outer tubes of the drive shaft comes loose and allows the two tubes to shift, destroying the balance. No repair for that.

If the front flex disk is cracked, no repair part is available and the entire shaft must be replaced.

Installing a different shaft without the flex disk and the '2 tube with internal dampener' rear half will work, but may be more prone to driveline induced torsional vibration. It's impossible to predict the effects, if any. It may be fine, or it may result in more wear on the differential and transmission.

Why don't you try the low cost solution. If it is too much vibration, let us all know. There were 100's of millions of cars built and driven billions of miles that had solid U-joints and did not have flex disks and dampened driveshafts.

[juiceman]

Replace Motor and transmission mounts

This was just completed a few days ago and now the vibration is getting worse. I guess everthing is in alignment now and it must be a bad joint. I am thinking the rubberband joint at the transmission because that is where most of the vibration is coming from

It got so bad I drove very slowly home and parked it until I can get the replacement shaft

Still not decided on the aftermarket or factory..

[Mayhem_J30]

definately sounds like the drive shaft now.

[texasoil]

Take a good visual look at the front flex joint and be sure the bolts are tight. Any visible sign of cracking or tears means replace.

[juiceman]

The shop is pulling the shaft to inspect the joints but the rubberband joint shows signs of flaking, no tears or breaks. Also the bolt are shows signs that the band have shrunk. I know rubber can shrink with heat.

I will know later today what the verdict is.

Called a couple of local shops who use Powertrain industries and have alot of good luck using them. No extra vibration when the rubber band joint is replaced with a std u-joint

Will let you know verdict later

[juiceman]

My mechanic has had a hell of a time removing the drive shaft to inspect the unit.

The bolts that hold the shaft to the rear diff are so tight and the way the bolts are assembled has the end of the bolt pointing to the rear which does not allow enough room to get a box wrench over the bolt. The open end just distorts over the bolt.

They have been soaking the bolts all day and will let it sit over night.

He said that the DS had a white paint mark on the saft and rear flange indicating that the shaft had been removed in the past.

I am going to get the history on this car because the last owners provided all the service records but maybe left a few out

Anyone have any input :help

[texasoil]

I do not remember having any difficulty with box-end access to those bolts and nuts. One DOES have to turn the shaft to the proper location for access.

If no luck, cut off the bolt heads.

[juiceman]

Finally cut the bolts off and the u-joints are very notchy

Will be ordering the DS today but do not know if I ma going stock or Powertrain

I will be calling Powetrain this am to discuss some lingering questions I have

I also inspected the fron rubberband joint closer and saw that there is a pin from the front and rear pieces of this joint. The pin shows alot of wear which is sticking out 1/2" form the fron part. Is it possible that his joint alos has problems because that pin has distorted due to the motor and transmission being out of alignment?

I am leaning toward Powetrain for a few reasons. I guess maybe I will be the NICO guinea pig

[Q45tech]

The white paint mark is factory where a technican spent a few hour deciding which of the 90 degree increments was best [phasing of ujoints vs minute runout deviations].

This is the step that is usually omited in shaft replacement as techs know that a new shaft will feel better than an old one and they usually don't have the dial indicator tools nor does the factory book include the time for this work! But it is fully outlined in TSB to correct problems with new replacement shafts if customer still complains and pays for the extra hours.

[Q45tech]

Ujoints get notchy unless they are stress relieved every 30-60k -been this way for 40 years.

[juiceman]

Stress relived, is this the bang it with a hammer someone mentioned before?

[texasoil]

banging on them with a hammer works. What happens is the grease around the small roller bearings gets stiff. Knocking them loose frees things up.

[juiceman]

OK I will be the NICO Ginea Pig

Ordered the shaft from Powertrain today, will be installed tomorrow and will report back in a few days on how it went

I guess we all have to take chances in life and I feel that this will not be a major mistake but who knows.

With the notchiness of the joints and the way the front coupler looked and the definate center bearing problem. I will risk the extra money to not have to deal with some of the problems again or have to remove and install again

[juiceman]

Had the new shaft in one day and the lower speeds are smooth as glass, the 50+ speed still have a vibe.

They are sending a replacement shaft but i wonder if there is something else at play here.

I will try the new shaft but does anyone have any input as to possible reasons.

I just want it to end.

[VimyJ]

Damn, juicy! I believe that you have new tires (what kind where they again?); balancing; alignment; engine mounts; transmission hangers; exhaust quests; drive shaft and still this vibration problem. Just so you don't think that you're going crazy, the J30 is an incredibly smooth car (my new tires demonstrated that to me). A new replacement shaft will narrow things down, I hope. Actually, I hope the new, new shaft encourages you to test the rev limiter in 4th gear in your silky smooth J. 130 mph in a J30t is very cool.

[SOCAL91Q45a]

juiceman ... what was the final status?

[juiceman]

Got G35

Still have J30 but have alot more time now to figure out

Replaced drive shaft and it did improve slightly but nothing major

Put car up on stands and ran to the speed I feel it and the motor is vibrating bad. Shaft and rear of transmission seem smooth

I am thinking it has something in the engine are/mount or somethin glike that.

Willpost more when I discover

Right now I am enjoying my G35 sedan

[sijoko]

Did you measure the runout on the driveshaft with a dial indicator?

There is a special procedure for driveshaft replacement in the service manual for the Q. I am assuming it would also be relevant for your J.

[Q45tech]

PREVIOUS Bad drive shafts wear out the diff input bearing and transmission output shaft seal [at the least] allowing the new shaft to wobble..............why you change them early and spend time indexing.

Why a 100,000 mile Q is not new............somebody has to spend at least a portion of the $30,000 in depreciation......say $10,000 to begin to return it to normal operating condition.