Shuddering on and off when going speeds above 40 mph

Check transmission fluid level.

you more than likely have a bad solenoid. have a reputable trans shop change out the solenoid pack located on front of trans right behind the cooling fans

did you scan to PCM to see if there are DTC errors from the TCM
the TCM is the logic that runs the transmission.
why assume it the TC or tranny, why not suspect engine misfire?
again scan it. (or get and engine tune,up, )

first, don't go 60 mph. next, are your lug nuts tight, wheels may need balanced. check front end tie-rods, idler arm, etc., this is unsafe, have your local mechanic check it out for you, make sure your lug nuts are on tight first.

it is missing if engine light is flashing

front or rear. you may have a shifted belt in a tire. to test this ... take off each tire and roll it down the driveway by itself... if it won't roll in a straight line or is very rough.... that tire needs to be replaced.

It's a step-by-step process. If it only happens on acceleration then it is a drivetrain problem. Start verifying from the outer cv joints and go in from there

Hi,

Appreciate the direct "Ask Me".

Initially, what comes to mind is probable faulty universal joints (U-joint), actually two of them and/or missing retainer clips. They would be coupling the transmission to the propeller shaft and then to the differential. The power train is nearly perfectly balance system and any missing needle bearing on any of the four ends of the U-joint wold cause a slight wobble on a particular speed. To check, the vehicle must be lifted and the propeller shaft yanked. There must be no noticeable play or slack.

Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information.

Good luck and kind regards. Thank you for using FixYa.

I would reccommend you go to the Nissan dealer and road test with either a technician or service advisor/manager to duplicate your concern.

How about the CV joint?? were they inspected for wear??