hey all, yesterday morning I noticed that between 2.5k-3k in second accelerating under load my truck was developing a shudder. But the end of the day it's almost constant in all gears and pretty violent. If I can find a sweet spot somewhere in the rpm range it's OK as long as it's not under load. But pretty much Un drive able. I checked the u joints. Which I had replaced once about 15k ago. Both seem tight and there is no play. Driveshaft does have some rotational play, probably more than normal but no more than it has had in previous inspections. The 3rd on the other hand... Leaks, whines, hums, it has done this for 50-60k I was just gonna let it ride till it failed. Always made sure it had fluid and just kept truckin. Can a failing rear 3rd cause the symptoms I've mentioned? Thank you. Truck is 1989 4Runner 3vze 5spd 395k

 

Please help with any info

 

i find it hard to believe that no one has any info on this at all. Other things I should check? Anything?

 

Jack up the rear end, both sides, and check for roughness in the wheel bearings, and in the pinion bearing.

Run the truck in gear and listen, if you are satisfied that your lifting measures are strong and safe.

May well be in the rear third, or it might even be something totally unrelated like an engine management issue, like TPS prob, or similar.

 

What have you checked?
Your truck has been to the moon and back
Check Motor mounts, Transfer Case mount, rear spring bushings etc

 

I would suspect clutch or flywheel.

 

that could be.
Do your problems persist if you have the truck in neutral and rev it?

 

Not sure if this helps but I had this issue in my tacoma, ended up being a combination of dirty MAF and faulty O2 sensor. Somehow it didn't trip the CEL.

 

Since I am dealing with this now....

I suspected the U Joints.
I REMOVED the drive shaft.
There was a tiny tiny almost impercetible "click" felt when twisting the shaft and the uJoint flange.

So I removed one uJoint (its a "custom" shaft, the spare uJoints I got with it are at my parents house 100 miles away, so I have no idea what size the joints are)

It turns out that the UJoints are Spicer 1310

Ordered new joints.

But now, paranoid, I'm thinking - rear wheel bearings?

So I put the truck in 4WD with the rear driver shaft missing...

No vibration - its no the wheel bearings! (and its obviously the drive shaft)

 

That is amazing that the driver's side motor mount lasted 394,000 miles.