Well if you get the vibration at the same highway speed regardless of whether you are in 4th, 3rd or 2nd (will it even go that fast in 2nd) then it is something between the transmission output shaft and the wheels.

If you get vibration at different speeds in different gears but same engine rpm it is something between the engine and transmission input shaft.

I can hear my diff growling when I have the truck in the air and its in gear. This is not exactly the same test as having the wheels on the ground, because the only load on the driveline is the wheels spinning freely in the air. I still think it's a useful test. You need someone in the drivers seat though.

But see, it occurs at any speed in any gear-the only difference is it only occurs if your on the gas, off the gas its smooth. Little gas or moderate to punching the pedal it exists, no gas-nada.

I did some more testing: Update:

Tried to pull the front shaft again, got one end off, the other end is obstructed by a guard and part of the frame that bolts on. Tried to remove that part, no luck bolts on way to tight (breaker bar and pipe no help).

I took some videos of all the driveshafts as best I could, also some of the cv's./ Excuse the choppy video. (waiting on youtube)

I also drove it in 2wd and 4wd while on stands again, I think the problems in the frontend b/c as soon as 4wd is locked in and you give it some gas wow does it shake and vibrate. I hit 25mph and i felt like the entire truck was gonna fall off. Also looked at the wheels w/cruise on and 25mph and at idle speed. The fronts seemed to wobble decently. 2wd seemed fine, it did shake but nowhere near as much-4wd locked in and like I said it almost shook off the stands.

One other thing, while under the truck and in 4wd the transfercase output to the front made these clicking noises-dunno wtf that is but I could hear them.

Also the cv axles all moved fine at a lower speed than the driveshaft, this is good?

Video, note the truck is on stands and in the air front/rear:
http://www.youtube.com/watch?v=9aYGq_VWP5Q

http://www.youtube.com/watch?v=Sjd4EBQ-MDM

http://www.youtube.com/watch?v=ZFFVEfTdN1I

Im not sure if you mentioned what kind of lift or size tires you were runnin, but you should try a simple front end alignment. I know that sounds way too simple for as much vibrating that is happening but i had the same problem. I was runnin 33's and when driving on the skinny pedal i felt mi entire truck shake, from the bed to the steering wheel to mi seat, and it was a very violent shaking too. I looked into getting hubcentric rings, but the company i called to order helped me out the most. The guy i talked to said its very common with toyotas that havent been properly aligned to vibrate very badly, esp. lifted ones.

If you do decide to try this, you have to do one thing. Make sure to find a good shop. Your everyday alignment shops probably will not and cannot balance and align a larger tire and ur T with a lift on it, they just dnt really know how. I went to a small, kinda sketchy shop a little off the beaten path, but every person there knew exactly what they were talkin bout, you could just tell. Not only did they give me a very good price, they were much faster than any other place and after i picked it up, The ride was smoother than the day i bought mi truck still on the stock 31's. Good luck and lemme know if this helps!

Maybe the transfer case got dorked?

Oh its aligned and right on the money, I saw the printed out specs and its within super close tolerances and I had a 2nd shop verify for me. Im runing just basic all terrain 31 inch tires, no lift.

Bam, possible but unlikely imho since the mount wouldnt have lined up as nice as it did when I replaced the trans mount

Long story short here:
I honestly know what it is now, I aint saying im stupid but it was hard to pinpoint.

Again FYI:
Vibe begins on take off with a shudder, then when you hit 2nd gear if your easy on the gas and it shifts before 2900rpm its not really noticeable. Give it more gas so it shifts at about 2900-3500rpm and bingo it begins to vibe badly, then levels off as it switches into 3rd gear (or it could be 4th idk).

Its doing the same damn thing it did for my pass side real axle shaft now. I can physically feel the stinking back drivers side wheel hop around as I take off and this explains why when I let off the gas and it isnt under load that the vibration levels off. Get on the gas again and that slack I mentioned before is taken up and vibration comes back strong again around 2900-3500rpm. Its doing it just like the other side did. Trust me I checked EVERYTHING I can possibly do in my own garage, removed everything, checked mounts, u-jopints- cv axles, etc, etc.

When the other shaft had gone bad it was doing the same thing but was so bad it was locking up the rear brake on that side, this isnt locking up the break as it isnt as bad, but its noticeable. I am gonna get a dial indicator tomorrow and check it as per the FSM best as possible. But I really think its that damned shaft as I rode more and more and more the past few days I can feel its on that side of the truck, I can feel the slack being taken up on that side in the drivetrain and it feels just like the other side but not as worse. I had only been riding around the block and up and down the road for maybe 10 mins at a time int he past.

So I thank everyone for the help, lets hope the test tomorrow is conclusive and its that simple. These trucks had this issue for eons, they switched to tundra axles no issues.

I hope you dont have to buy another axle. If you take the axle out and it's straight maybe it's just the bearing.

The bearing for the old axle is just a 6308 w/ shields on both sides.

Im hoping so, i honestly dont fancy pulling the entire axle out tho-not a fun job by any means.

It was honestly stupid of me not to think of this before, but I thought to myself-cmon now both of them couldnt have been bad, could they?? The wheel hop on that side and the vibration when you gave it gas then stopped when you let off really sealed the deal.

Lets hope its just a bearing or even the shaft..

Here is the bearing check



(a) is trying to show the thrust play - moving in/out of the axle

(b) may show a bent axle

I cannot see how you can pass these tests if you have problems.

The actual shaft runout check is later on in the fsm, they want you to mount the shaft in a stand and check it along the length while it's spinning.

I think if the axle end is wobbling around like the other one the brakes would be glazed too. Right?

Checked as per FSM, nothing is amiss. No difference in play between the good one and the other one thats original to the truck. Both measure up fine with the dial indicator. The brakes are fine, no glazing a all, no locking like the other side would.

I think its stinking wheel hop, cause although it manifests it self as a bad axleshaft, all checks come back fine. I cant find anything else wrong at all, springs, shafts, frontend all seem fine, motor/trans is fine too. As It ake off I can feel it hop, my grandfather noted today that why the heck is my truck so damned torquey, he had v8s with less power. Something funny too, everyone always says the trucks are slow, imho it isnt at all, infact it has tons of power out of that V6-perhaps the guy before me had some engine work or had an RV cam set installed or soemthing when they did the engine-cause otherwise I dunno.

Someone suggested I get some antiwrap leafs put on, I found some on jcwhitney and will give it a shot. If it improves then we know what it is, if not I feel the thing is livable and will just pack it in. Or maybe ill work up traction bars or something.

You might want to take a look at this website. http://www.4crawler.com/4x4/CheapTricks/Driveline-101.shtml

I think that you have posted thinking that you were getting some movement "axle wrap" of the rear pinion and that was causing your problem, etc. This might help explain it better and possibly give you an area to at least look at. I am wondering if the stock springs have weakened (saggy rear end syndrome) and is helping to give a little more vibration, changing the angle of the driveshaft slightly so that the angle with the rear pinion is not correct under load. I know that I am not explaining it properly.

I have a similar problem (vibration) at about 60-65 MPH that I cannot get rid of. I am doing one thing at a time to hopefully find the problem and I have done most of the stuff that you have already done here with no fix, yet. My next move is to replace the wheels and tires and see if it goes away. I think that my 2 rear wheels are bent slightly and give me that at speed. I am not having the problems you are having with wheel hop, yet.

Good luck!