93 G50 vibration help

[marcyprojects]

Bought my 2nd G50 last month and first of all im estatic to have another one. Bought a clone of my first one that I owned 9 years ago. was my first really nice car that I bought with my own money. I also have a 95 S14 and I have owned/restored 3 of them as well. Anyway, Ive got the new Q pretty much restored except for this one vibration issue. Vibration is felt starting around 30 mph, most intense around 50, and it also felt while decelerating. Wheel doesnt shake at all, all is felt under my butt in the seat and in the armrest.I also find that its worse in the mornings when the temps are a bit cooler. Ive done a great deal of research, much done here on this forum but a lot of it is bit dated. Ive tried everything I can with mixed results which confuses me even more. Heres the run down:

1. Drain and fill transmission fluid - Car engages in drive/reverse bettter, still vibrating

2. Check transmission mount - found it had been replaced, mint condition

3. checked motor mounts -not an inch of movement, prob replaced with transmission mount

4. Flushed transmission - I did this slowly 4 quarts at a time, now has some sweet spots where vibration can be minimized if I feather the gas

5. Changed transmission filter/ added new fluid - seemed to respond within the first test drive, vibration was back later that same night. drain/ added about 4 quarts?

Anyone delt with anything similar recently?I also found it hard to get a good reading on the fluid level maybe im just short and dont know it?

[BCC93QT]

Had a very similar issue on my 92. Turned out the bearing on the driveshaft was bad. On the 90-93 they cannot be replaced. The 94-96 can. Just grab a used driveshaft of the later model out of the junkyard. Can tell if its bad or not by just pushing up on it and you can probably see some splitting in the rubber.

[marcyprojects]

Had a very similar issue on my 92. Turned out the bearing on the driveshaft was bad. On the 90-93 they cannot be replaced. The 94-96 can. Just grab a used driveshaft of the later model out of the junkyard. Can tell if its bad or not by just pushing up on it and you can probably see some splitting in the rubber.

Yes that was my next course of action. where is this rubber? where should I look?

also, many of these i find for sale are selling just the rear portion and most of them are for models without traction control? does that matter

[Brew Q]

Wow, learn something new every day. I have the exact same problem. I was reading old threads on it yesterday, figured it was the trans mount, but now I'll know to check the driveshaft too. Now if I can just get a free day from work.

My vibration is also definitely present between 30 and 50 mph, but is worse under load, can't feel it much if at all if I coast or put it in neutral while rolling.

[marcyprojects]

Wow, learn something new every day. I have the exact same problem. I was reading old threads on it yesterday, figured it was the trans mount, but now I'll know to check the driveshaft too. Now if I can just get a free day from work.

My vibration is also definitely present between 30 and 50 mph, but is worse under load, can't feel it much if at all if I coast or put it in neutral while rolling.

Ditto on all that man. Been here at the job looking at info for the local junkyards in jville. Just found a new yard here that could have one for as little as $25! Just need to find out if I definately need one from a TCS enabled car or not. My car has TCS but it hasnt worked since I got it.

[marcyprojects]

Any other insights? im about to hit the junkyard tomorrow to hopefully snag a 94+ driveshaft. Still not sure if I HAVE to use a driveshaft from a tcs enabled car but looks like it so far. Anyone know?

[marcyprojects]

Had a very similar issue on my 92. Turned out the bearing on the driveshaft was bad. On the 90-93 they cannot be replaced. The 94-96 can. Just grab a used driveshaft of the later model out of the junkyard. Can tell if its bad or not by just pushing up on it and you can probably see some splitting in the rubber.

I was able to find out what rubber u meant btw. It was obvious, just wasnt thinking straight.lol

[BCC93QT]

30-50 is about correct as I recall. I noticed it stopped from about 50-70 and then under harder acceleration on highway speeds over 70. I am not 100% sure but I think the driveshaft on a Q with TCS is slightly shorter or longer.

[BCC93QT]

Wow, learn something new every day. I have the exact same problem. I was reading old threads on it yesterday, figured it was the trans mount, but now I'll know to check the driveshaft too. Now if I can just get a free day from work.

My vibration is also definitely present between 30 and 50 mph, but is worse under load, can't feel it much if at all if I coast or put it in neutral while rolling.

Putting it in neutral will have the same results as the wheels are spinning, essentially spinning the shaft. But will be more noticeable under load.

[mattd1979]

Hey marcyprojects... It's Matt, the guy you ran into at the yard. It's nice to know another Q45 owner from Jax. I'll PM you my phone number and such so we can meet up.

Matt

[marcyprojects]

Hey marcyprojects... It's Matt, the guy you ran into at the yard. It's nice to know another Q45 owner from Jax. I'll PM you my phone number and such so we can meet up.

Matt

nice meeting you as well. might need to call on ur advice on this whole driveshaft thing. still having issues.

[marcyprojects]

so after 10 hours of junkyards/labor, I still have vibration... It is slightly less than before but still very noticable. only felt between 40-50mph only. Not quite sure what the issue is but there were many findings and questions that came up along the way. right now I only have one thoery about where I might have gone wrong. Heres the rundown:

1. Found that the driveshaft that came with my car was actually an aftermarket replacement. Non nissan. had a new but odd looking center bearing like some of the ones on ebay ive seen.

2. While me and a buddy were mounting the replacement 1994 driveshaft we realized that we didnt pay close enough attention to the bolts that mount the front of the driveshaft to the transmission.

there are 6 bolts in total but there are only 3 holes on the driveshaft and and 3 on the other side. I lined them up and bolted them together but it doesnt look right to me as that leaves 3 bolts that arent really attached to anything but that rubber damper in between? Also the 3 bolts that are tight and holding most of the weight, seem to have just enough length to tighen? just seems a bit short to me.I hope that this is the fix cuz im out of options.

could somone possibly post a picture of an correctly mounted and bolted driveshaft on the transmission so I can see? thx in advance.

[marcyprojects]

so after 10 hours of junkyards/labor, I still have vibration... It is slightly less than before but still very noticable. only felt between 40-50mph only. Not quite sure what the issue is but there were many findings and questions that came up along the way. right now I only have one thoery about where I might have gone wrong. Heres the rundown:

1. Found that the driveshaft that came with my car was actually an aftermarket replacement. Non nissan. had a new but odd looking center bearing like some of the ones on ebay ive seen.

2. While me and a buddy were mounting the replacement 1994 driveshaft we realized that we didnt pay close enough attention to the bolts that mount the front of the driveshaft to the transmission.

there are 6 bolts in total but there are only 3 holes on the driveshaft and and 3 on the other side. I lined them up and bolted them together but it doesnt look right to me as that leaves 3 bolts that arent really attached to anything but that rubber damper in between? Also the 3 bolts that are tight and holding most of the weight, seem to have just enough length to tighen? just seems a bit short to me.I hope that this is the fix cuz im out of options.

could somone possibly post a picture of an correctly mounted and bolted driveshaft on the transmission so I can see? thx in advance.

Also wonder if maybe I just need to rotate the shaft 180 degrees so that it lines up with the same spots as the car the shaft came from? so many questions...
I had no idea this was so involved. Spoke with a drivetrain shop earlier today also and its starting to get pricey.. Might have to cut my losses on this car and let it go

[Brew Q]

Felton Auto has some OEM driveshafts - I may do this myself (instead of wasting my time at a junk yard). It'll cost you more, but they stand behind the parts they sell.

This is copied and pasted from there inventory search:
http://www.feltonautoparts.com/asp/parts/

Change vehicle selection Change part selection
Year Model Exact Side Description Code Price
1996 Q45 NA 802 0.0 $100.00
1995 Q45 NA 802 0.0 $100.00
1994 Q45 Yes NA 802 0.0 $100.00

I would call them too..., shipping won't be cheap either, but you'll know you are getting OEM.

[marcyprojects]

thx for the info man. After another long day at work, researching between phone calls im about 99% positive where I screwed up. Looked at pics of some similar cars and discovered I infact have the flex disc mounted wrong between the driveshaft and the transmission. I have unused bolts because Ive got the driveshaft and the transmission bolted directly to each other with the flex disc in between. I need to turn the shaft so that it fills the empty holes and allows the flex disc to do its job.lol. Working late night after a long day, neither me or my buddy could see it but now that my mind is rested its obvious. Hopefully the wife will have mercy on me and let me put in another hour in the driveway tonight and i should be golden.

[mattd1979]

I know that your supposed to put a line across the yoke and the coupling to the shaft according to the service manual so that when you take it apart, you can line it all back up so that there aren't any balance issues.

Matt

[BCC93QT]

I don't recall this job being difficult nor so involved... Maybe I am just used to the more complicated things the Q can throw at you.

[marcyprojects]

UPDATE : Got my bolts aligned right. all is good. Maybe one day I'll get out of the habit of working til 2am. Too many errors like this can happen. But, the old gal is back to riding smooth.

[BCC93QT]

Feel free to send me a case of beer for my services... Good job

[marcyprojects]

Feel free to send me a case of beer for my services... Good job

Lol. Next time I go home (Hartford, CT) Ill look you up. not too far from me there.