So I have an 03 g35 its been doing this for awhile. Every morning first start of the day if I turn out of neighborhood and accelerate between 40 and 60 I get a pretty bad shudder or vibration for about half a mile. Then it’s gone and doesn’t do it at all the rest of the day. Any thoughts or ideas would be great. I have replaced a lot of parts on this car basically restored but it is my daily and I am running out of ideas.

 

Any idea if it's front/middle/rear on the chassis? Rpm or speed based vibration?

My guess would be tires, if it's been a while you should have them balanced you should have it checked.

Inspect the propeller shaft carrier bearing as well, they fail in various ways on this vehicle. Mine started clunking on accel/decel but I could definitely see the "internal goo packing" around the bearing failing in a way that causes vibration until it's shaken itself around a bit.

 

I don’t think its the tires but I am getting 2 new ones on the passenger side Monday. I picked up some screws. All four tires are new. I would say the vibration feels like passenger rear. I have not done anything to the driveshaft yet as far carrier bearings. But it all seems in good shape. Plus it only happens once in the morning. I would think that tires would be consistent. I recently replaced diff bushings thinking that might fix it but no luck.

 

Replaced the two tires on passenger side. It did seem to help some but the vibration is still there. I think net time I get paid I am going to either replace rear axles or rebuild driveshaft. I have 180k on this car and I haven’t done them yet. Any suggestions on brands for u joints and carrier bearing? I think if I do axles I’m going to replace hubs and axles with g37 factory option.

 

Were your tires balanced and did you get an alignment?

 

Tires are balanced. Alignment is good. I recently did the alignment after I replaced rack and pinion. I have been through this car several times and I can tell you it’s nothing obvious.

 

^^
Possible vacuum leak that disappears upon warm up?
Instead of just throwing parts why not just spend the diagnostic fee at your local Infinitii dealer?
A consult tool can confirm the problem
Your vehicle is seventeen years old and many parts are at close to end of life

 

Is this vehicle a 6MT or a 5AT ?

 

It’s a 5at. I know it’s not engine related or a vacuum problem. I could take it to Infiniti but I doubt they would be able to duplicate it. I have been a mechanic for 20 years. I don’t mind throwing money at this car it’s been my daily for 9 years. If I suspect something might be wrong I try to upgrade it.

 

This car literally runs and drives perfect all day after. I think likely it’s a driveshaft issue or a cv axle.

 

I never heard and answer if you thought the vibration was related to engine rpm or travelling speed.

As for the driveshaft, it's about $150 for a new carrier bearing, I didn't bother trying to source U-joints to try rebuilding it because that would probably be another $75 or so. I decided just to go with an aluminum driveshaft which cost me $525 shipped to the house.

I REALLY doubt it's a CV axle issue but you can check that yourself by getting the vehicle on jackstands when it's cold and trying to get any play out of the shaft. Also look for any play on the differential output stub shaft.

Just out of curiousity, do you have the "axle click" when you move the vehicle first time for the day?

 

No noise or clicking. I don’t think it it rpm related I can take my foot off the gas or accelerate and it doesn’t change. It’s just there first acceleration between 40 and 60. Goes away past 60 and never comes back. Also if I drive it a bit in the neighborhood then get to speed I don’t feel anything.

 

Any difference if you let the engine get FULLY up to temp before you drive?

Does it go away after the first time you do some moderate braking or will it just go away on it's own without using the brakes at all.

 

Does not matter if I let car warm up before driving either. What brand carrier bearing would you recommend? Also did you replace both driveshafts with aluminum?

 

Maybe braking does help. It all depends which way
i go
to work. I go one way trough neighborhood and stop
at Like three stop signs and then get to speed no vibration. I go the other way tap brakes once and get on highway vibration is there.