Pleas help me diagnose my vibration

[DHC6twinotter]

I don't have any good suggestions, but would a bad torque converter cause vibration issues?

[fustercluck]

Why did you only replace the passenger side rear axle shaft? As you described the vibration and used 'hop' in association, it reminded me of my 84 truck. It had a pronounced vibration that I felt under the seat at a certain RPM range regardless of the RPMs of the motor/tranny.

Turns out that both rear axle shafts were slightly bent. You replaced one and got some improvement. While we are throwing parts at it, I would give the other shaft a shot.

I am sorry you are so frustrated. It's no consolation, but if you give up, don't sell the truck. You should part it out on ebay and the like (forum classifieds), you'll make twice to three times the money....especially since T-100 parts are as common as horse feathers.

[YotaFun]

Why did you only replace the passenger side rear axle shaft? As you described the vibration and used 'hop' in association, it reminded me of my 84 truck. It had a pronounced vibration that I felt under the seat at a certain RPM range regardless of the RPMs of the motor/tranny.

Turns out that both rear axle shafts were slightly bent. You replaced one and got some improvement. While we are throwing parts at it, I would give the other shaft a shot.

I am sorry you are so frustrated. It's no consolation, but if you give up, don't sell the truck. You should part it out on ebay and the like (forum classifieds), you'll make twice to three times the money....especially since T-100 parts are as common as horse feathers.

HEY MARC!!!
What did I say to you?

I am all with fuster on the one, I would replace the other shaft!

[CJM]

Yes Avy you are right and so is Fuster imho.

It works like this:
1. Motor mounts are def bad, and only cost 50 bucks to do.
2. Cab mounts are bad and only 100 to buy them all and my freetime or pay to have them done..whats that maybe another 100 in labor
3. The mount under the diff is probably dealer only but what could it be, 100? Easy to install
4. An axle shaft, associated parts, etc is 500 bones.

I dont have 500 bones atm to play with nor the time to do it.

Im curious Fuster about your vibration issue. Is it very similar to mine?

@Frank: Although I still felt it-remember even tho the rear isnt connected-the shaft in the axle still turns and the leaf spring is still connected to the truck and thus you feel it. However a motor load issue could be it. The truck has no vibration unless the wheels are spinning!

I dunno. Its so many different thing its insane. One friend said it was in the trans, another said the drivetrain/shafts, another says maybe its the cab mounts, then yet another says motor mounts, etc etc. All of these thinks can be it, but I just lack the time. I finally gave up and am paying someone to do it for me. The final straw is the other axle shaft, althought it doesnt seem to be bent I feel the axle wrap on that side and that sides the vibration is on.

I just dunno, but I am making more money at work since we got busier and willing to try these few things.

[reggie 00]

If you want to know for sure and you can squeeze the time,

Swap axles around.

Put the known good in the suspected bad spot and see if your wrap and vibration follow the suspected bad axle.

Its the rear so both side are the same right?

it would really suck to drop 500 bucks and find out it was just a small part of the problem again.

jmo

[2ndGen]

have you checked your pinion angle? it could be the problem for lifted tacoma if the rear drvie shaft has u-joints one on each end. probably a good idea to get a pair of (leaf)spring shimms to correct the pinion angle.

i did a little research on that last month, it's not an issue for my 4runner because it has double-cardan joint(CV) and coil springs. but on a taco, the pinion angle is better to be less than 2 degress.

[fustercluck]

Yes Avy you are right and so is Fuster imho.


Im curious Fuster about your vibration issue. Is it very similar to mine?

Can't tell until I feel it, but as I read your description again, a bell sounded and reminded me of my 84.

If you don't have the cash to throw at it, you can still eliminate it by removing and taking it to a machine shop. have them throw it on their lathe and put a trueness gauge to it (that's not what it's called, but I forget the name...). That way at least you can know. Also, and I think we are zeroing in on the trouble, you should have your entire rear axle checked for trueness. I know it's not likely, but you could have tweeked it somehow.

If it turns out that your axles are true, the housings are true, the alignment is correct, you are not 'dog tracking', and your thrust angle is right and you still have hop, you may be SOL....

[CJM]

Easier said than done Reggie.

I got lucky, a person I went out to today to jumpstart is giving me thier 99 ford taurus for free. All it needs is a headlight and balljoints. I dont care its beat up, I really dont care so long as it runs and drives. This gives me a chance to diagnose my issues further. But in reality it cant be much else, not much else is left to cause the rear to hop like that. The the rear axle itself CANNOT be bent, toyota axles are SUPER thick and strong compared to domestics with axle tubes. Worst case I replace the shaft and nada, gears? Doubt that since I changed the fluid more than once to be sure and no chunks of cshavings.

have you checked your pinion angle? it could be the problem for lifted tacoma if the rear drvie shaft has u-joints one on each end. probably a good idea to get a pair of (leaf)spring shimms to correct the pinion angle.

i did a little research on that last month, it's not an issue for my 4runner because it has double-cardan joint(CV) and coil springs. but on a taco, the pinion angle is better to be less than 2 degress.

Pinion angle hasnt ever changed, there is no lift whatsoever. It also has a double cardan shaft (2pc) so thats not it.

[fustercluck]

What does your rear view mirror do when you feel the vibration starting? If it vibrates, does it continue at all speeds or does it 'smooth' out?

[CJM]

What does your rear view mirror do when you feel the vibration starting? If it vibrates, does it continue at all speeds or does it 'smooth' out?

I never really looked Fuster, I dont think it vibrates tho.

Here is exactly what happens (to reiterate):
From a dead stop you hit the gas pedal. The drivers side rear of the truck feels like wheel hop. Could give it a little gas or alot of gas it hops a bit. As you pick up speed this same side vibrates and I can see in the mirror the bed is kinda vibrating.

When you let off the gas at speed the vibration lessens or possibly goes away (could just be lessened enough that I dont feel it tbh). Back on the gas you can feel that side hop as you go.

While driving you can feel the floorboards right under and next to the door vibrate-the cab mount there has a good half inch of play and I can move it all about. That same side the motor mount seems to be looser than the other side. Incidentally this is also the side there is a bushing of some kind for the front suspension thats totally flaking apart too.

There is no vibe felt in the wheel, the pedals, the seat really. ITs the floorboards and the whole truck itself.

So I dunno really, the main problem is I cannot do the work myself I just have no time and before I had no money as work was super slow but I get paid by a per job basis, not hourly. So it was tough.

Right now I am having the motor mounts put in, see if improves. Then I will see about cab mounts, that bushing and see what happens, then finally as a last resort the drivers side axle shaft. Im really leaning towards the shaft, but those other bushings and junk could have some effect too.

Like I said in the very first post: I have eliminated ALOT of other things by replacing or checking them thoroughly. So its down to a very few select options.