I have got the shakes! Must get to the end of my vibrations.

[elwesso]

Thanks for the reply tech..... I agree about the 2 piece driveshaft, its defintely the way to go for vibration free operation...

I think I have a plan on what im going to do next, since I dont have time to buy a driveline inclinometer before I work on the car this weekend, im going to do very basic diagnosis... My plan is to put a jack under the transmission (likely a bottle jack so it doesnt move) and ever so slowly adjust its height to see if propping the trans up a little helps, which would then tell me if the transmission mount is bad. Since the motor mounts were ever so recently replaced (less than 30k) i doubt the motor mounts are bad, however, the trans mount may be indeed bad. if that doesnt do anything, then i guess im stuck

[elwesso]

Just an update for those who are mildly interested.

I called powertrain industries, for those who dont know thats where i bought my driveshaft, and since it is still under warranty i can have them send me a brand new shaft for free...

I think what is causing my vibrations is my differential.... which i will be replacing tomorrow with the one from my old Q..... I layed under the car with the wheels spinning off the ground and i could see the runout on the input shaft..... Cant be good at all..

Will report back tomorrow after I replace the diff.... Im really hoping this solves it, because i dont really like messing with the driveshaft very much....

[maxnix]

Good luck and let us know.

[Q45tech]

An imbalanced [as installed] or uncorrected angle shaft will quickly wear out transmission tail shaft bearing/seal along with differential nose bearing/seal.

Why factory uses 2 piece to prolong all systems by allowing each section to properly mate.

Seen it on other cars converted to single piece drive shafts [BMW/Mercedes diff failure].

Since a new diff costs $2500 less than a good idea to redesign a $600 part.

But then again you can get used worn diffs for $250-$450.

I feel that a new oem driveshaft is a better investment which was installed at 120k..............still no where near as bad as the oem got at 100k.

[elwesso]

Well i got in there, and the differential isnt going to come out... someone previous to me rounded off one of the bolts on the halfshaft so i cannot disconnect the halfshaft from the diff.... No room to get any tools up there, either...

so im just going to consider it about an hour wasted, put the thing back together and go from there.....

Just FYI, my driveshaft is an OEM replacement, that doesnt have that flex disc in the front and has replacable U joints and so forth.. at this point, i dont think i will invest in a OEM driveshaft....

[rsiwicki]

how the hell did some idiot round off a half shaft bolt. My rearend has been R&R over 4 times in the last 18 months and my bolts are perfect...although they are tight as hell and require a long wrench to correctly tighten and remove because you can't get a torque wrench on the bolts due to lack of space.

that really sucks about your vibration problems....I know that can get old very quick as I had a Bronco that would always shimmy, but then again it went 4x4'ing often so I suspect that was the cause.

[Q45tech]

If you think about it with new parts CORRECTLY installed and correctly positioned and correctly balanced there will be no vibration.

Just changing a few things here and there because they are cheap usually doen't make the car new.

I am guilty myself and try not to do major system overhauls frequently.

But I have changed everything from the wheel bearings, hubs, diff, subframe, drive shaft, transmission and mounts and motor mounts......pretty much everything in the drive system except half shafts over the past 185,000 miles [7 years]..........some lasted 120k, some 180k, some 235k........ the diff which lasted 235k was replaced with a 60k wrecked unit...which now has 70K +60 =130k.

I'm ready for motor mounts again [185k].

[elwesso]

Im not sure how they managed to do that, but from what I can tell the diff has been removed a few times... im not gonna worry about it...

ive decided ill likely replace the driveshaft and teh trans mount and see what happens from there.... if that doesnt fix it, then ill look into the diff.

Regardless, i put it all back together because i got sick of messing with it... no harm no foul... However, i think i would have been more pissed if my TCS differential would not go into my non TCS car, which I didnt think about until i was halfway disassembled anyway.....

We'll see what happens with the driveshaft/trans mount, but it will probably be a couple of weeks before i feel like fighting things on the underside of the car.....

Too bad nissan couldnt have made about 1/2 in more space, otherwise you could get a socket on there..... Its OH so close to being able to get a socket on it...... oh well!!

Interestingly enough, i shimmed the driveshaft with 2 washers and I think that may have helped a little.... however, when i was under there with the wheels free spinning i could hear the center bearing clicking, so i think i need to deal with that first.....

[PopPop]

Wes you should have taken a cut-off wheel. grinder, or heat treated chisel blade to the bolt head. They make hardened blades for heat treated bolts. Snap-On also makes a wrench especially for striped bolts and nuts! We also tack-weld nuts onto the head of striped nuts too remove them also!

[elwesso]

The problem is I can hardly get a wrench on it as it is... I have these things for rounded bolts, but I didnt have one for the 14mm bolt head..... Either i never had one or i lost it.....

Im glad you posted in this thread, because I wanted to report that the vibration does not seem to be as bad... I dont hear and feel the driveline vibraiton like i did before...... I can DEFINITELY tell the tires are out of balance after having the wheels up in the air like I did... I may go nad have the tires balcned and see what happens.

[PopPop]

That's very good news for your Parkinson's Disease! Some relief is better than none!

[johngalt]

Thanks for posting this Wes. As I am still a n00b to NISMO technology (in terms of getting into the nitty gritty as opposed to just letting a dealership take care of things) I now have a few good ideas on what I can to do try to eliminate some 'negative vibes' I am getting with my car.

AFAIK everything on my car is stock, and I have yet to make it up to T3 to get a real inspection to see what all is wrong, what needs to be fixed and how to fix it. That being said, I am not sure when I *will* be able to make it up there, and not being a major overhaul / repair kinda guy to begin with, a lot of what I see here I am pretty sure I can never do myself anyway. But with the info and updates you posted at the very least I can check out rotors / pad, wheel balancing (and high speed balancing if anyone around offers it) to cut out some serious vibes that I get in the 45 and 65 mph range (I haven't found a cop that I know well enough / track where I can test my car without getting busted for breaking speed laws yet).

[elwesso]

Hey, John

All of the things that I have done to my Q are not entirely complicated..... only a few of the things i needed special tools... 90% of the stuff I do can be done with the 96 piece craftsman tool set that I got at sears...

The main thing is confidence... Just go in there, use common sense, get stuff done, and save some money....

[johngalt]

might be, but I prefer to learn by watching - if I have never done it before, I am loathe to attempt to do something on my own without a "full and proper" set of instructions. By full and proper, I basically mean n00b proof - exact instructions, especially containing warnings and advice on how to do things to prevent damage / destruction - and damage and destruction are two things I am *great* at!

But the main thing I want is a a set of FAQ's / reasonably easily accessible info (without having to use the search tool, b/c it's major problem is that the searcher needs to use correct terminology to find an answer sometimes) such as a PDF doc / flow chart / spreadsheet with things that I should look at / be looking for considering the 143+K miles on my car. I have found a lot of them, but then again, not having anything other than the pre-inspection on it I don't have a basis to compare to to begin with.

Ah, well. At least I get entertained by the stories and am learning some things here (like to possible look for a new rear end for my car to give it better acceleration).

Also, I am pretty damn positive that I need to obtain the FSB fist and foremost so I can get acquainted more in detail with some of the systems in this car.

[maxnix]

FSM and TSB are what you need. Go download them your next free day.

[johngalt]

Download them from....?

EDIT: Added the following:

I can always D/L them at work - I have access to several off site FTP / web spaces from 1and1.com *and* almost always have my 512 MB USB Keydrive with me, so....

And I guess i should look around the forum more, since the obvious answer o 'where' would probably be something along the lines of "right here!"

[elwesso]

I have the FSM, ill send you a link in my email reply.

[maxnix]

Download them from....?

http://www.nissan-techinfo.com/infiniti/

[johngalt]

Muchas Gracias.

[elwesso]

Just thought I would update...

I shimmed the driveshaft with 2 washers, and now the vibration seems to be better when you are on the gas, but when you let off the gas it gets worse.....

What does this mean?