rexrunner

2003 Prerunner, 2.7L, auto w/OD, regular cab (all stock except corbeau seats GTS II)

Hello new to forum.

I have been all over this and other forums and I seem to be getting closer to fixing this issue.

First my frame is not bent. The dealer has verified this prior to warranty work (pinion gear replacement, motor and transmission mount replacement, drive shaft replacement and new Michelin tires balanced good) all due to a loud cyclic vibration at 45 to 50 miles per hour that occurred after lower ball joint recall work was done. Vibration is barely noticeable now. And I have no center support bearing due to being regular cab.

During highway trips it seems the ride is too soft and dips often and it almost feels as though engine is missing but it is not (been verified also).

Also around town while driving, my shifter movement is normal but at times would have a slapping sound (you can feel it in the shifter and floor at shifter). If I punch the gas numerous times I get a slapping sound and yes I greased the u-joints and the slip yoke I grease the hell out of it about 30+ pumps.

From a stop with wheel turned hard left or right I punch the gas and I get a thud sound from rear. Mostly happens on right turns while accelerating, hammering the gas.
Also at times if I am hitting gas and let off and hit dip in road my shifter makes a violent slapping sound not the normal bounce.

Is this axle wrap or just soft annoying springs?
I think my rear RIGHT leaf spring may be causing my pinion angle to be off slightly and while I am steady at 50 miles per hour the torque maintains this faulty angle causing the vibration.

Today I measured the open space between rear leaf springs to frame (truck was on flat level ground):

Left rear 8.5?
Right rear 8?

Also my springs do not arch.

Also my driver side leaf spring seems to have been replaced (you can see shipping labels on it).

I think the previous owner had a bad driver side spring and replaced it only.

I am considering Alcan spring pack with new shocks and maintain stock height for my 265/70 16 (no off road).
I am wondering if I put a set of Alcan springs on if there would be any improvement??

I am thinking my pinion angle is changing.
All this started after my ball joint recall fix.
I am heading to dealer in the morning..

Thanks for your help in advance...