Ok I have a 96 T100 SR5 x-cab, 3.4L V6 4x4, 197K on truck/trans and 50k on newer engine. If I cant figure this out im just gonna have to dump it off on someone..

It has a CONSTANT vibration, it vibrates the floor, seats and the steering wheel-infact the whole truck pretty much. It can be felt in any gear fwd or reverse, at any rpm range, take off, when on gas, strangely off gas its smoother but still there. Give it less gas and its not as noticable-still there tho. I just drove in fwd (4x4 with no rear driveshaft) and its still there

What I have done:
-REAR 2pc Driveshaft balanced, propeller shaft replaced, tailshaft replaced, u joints all seemed fine to them, I just pulled the shaft and they seem fine to me. They have NO play whatsoever.. done march 08

-All new brakes all the way around, calipers, rotors, discs, shoes, drums, wheel cylinders. No issues at all with brakes. done this past year.

-Tranny mount replaced, was worn. done over this past summer

-Motor mounts checked, all fine done this past summer

-Rear passenger side axle shaft, replaced the bearing in there as well. T100s are known to have these go bad, I had it replaced this past summer and the vibration got much better. Before I had wheel hop severally-its gone now entirely. Could the drivers side be bad??? No way to tell without pulling it and bearing is 1x use, all parts are superseded by tundra parts so they all need to be replaced

-About the only thing I havent done is give it a tuneup, I got it with 50k on a new engine and I have only put on 15k so yea.

-The tires arent the greatest and cannot be balanced any better(trust me i been to 3 places). But even so off the gas truck is smooth. But, even so I traded someone else for his one day, still vibrates.

Whats left:
-Bad motor mounts. I checked these and so did a mechanic friend and my own mechanic-all said fine. Motor does not move around in engine bay when on gas powerbraking, all rubbers seem intact.

-One of the bodymounts on the cab isnt snug looking, I dunno but the rubber isnt against the mounts to well imho.

-Bearings, front, rear what have you.. no hum or whine, but maybe?

-Trans has worn gears?

-Cant be the rear, thats disconnected right now and i changed the fluid 2x thinking that. 1st time no metal in there, 2nd time same. Fluid looked perfectly fine, no whine from the rear. Front fluid looks fine too, no water in it.


I just dont know what to do anymore, a friend states it could be bad wheel bearings in the front and or rear. He drove my truck this past saturday and things after eliminating the rear driveshaft it could be the front ones as the steering wheel vibrates-but would the floors and seats vibrate too? He states that perhaps when I am on the gas they have more force on them and off less force means less vibration?

I just dunno anymore, this is becoming a headache as I cant drive the truck this way, its drives me crazy. What the heck else is there that could cause it to vibrate? I mean I replaced/checked nearly everything that is related to the drivetrain that one can service. about the only thing I can think of its the trans.. I did hear about problems surging with worn out plugs and wires not firing right and causing surges due to them not having a powerfull enough spark-but thats way out there imho.

So can anyone help me, throw some kinda ideas out? Im open to just about anything at this point.

Hmmm...

Guess you could always hook up a transducer to various suspect areas to record the vibration and see what the frequency is of the vibration.

If the bearings are suspect...pull the hubs and check?

Could it possibly be the motor? Pull that and have it checked on the stand? Could it be the flywheel?

Thats just it, im stumped and so is every single person I talk to or take it too.

A friend and I discussed that perhaps the other axleshaft is bad, if replacing the one helped significantly then the other might as well be it.

I just dont know wtf to do anymore. So far its been to toyota (who kept hehawing back and forth it could be this or that and wanted 90 bucks from me for a looksee with no guarantee of what it could be-I left), my mechanic who diagnosed the other bad axleshaft in the end after the other work was done an sts who didnt have a clue, a friends shop who replaced the little parts as a first step, and the driveshaft guy who says my d/s is fine.

I think im gonna start by replacing wheel bearings in the front and put on the tires I got with rims that are known to be true. While im at it ill check the rear shaft for runout.. if all else fails another rear shaft..

Thought you tried swapped wheels and tires. I have one rim that is a little bent and I get a narrow rpm range wobble at about 62. Does not seem to affect the tire, so I just go faster or slower.

If you have a manual transmission, can you take it to some hill, push in the clutch and turn off the motor? Don't do it on a crowded highway since your power steering and brakes will lose effectiveness.
If the vibration goes away it's in the engine. If not, it's elsewhere.

How about connecting the rear drive shaft and removing the front hub plates? That should allow you to tell if it's the front drive train out to the bearings at least.

Also, it could be a tire too. I had a tire on a car once that must have had some internal cordage defect which caused quite a vibration. I don't think the balance was affected but the ride was. Perhaps swapping your spare for each of the four tires.

Does the vibration peak at a certain speed or just get worse as speed goes up? Is it related to engine RPM or just vehicle speed?

Chip

I did swap tires and wheels, still there. I had known good tires/wheels on there and drove the other truck with them on there and mine on his-mine had some vibe but not like my truck does where the seats, wheel, floor all vibrate.

No manual trans, I checked this. Truck running go down the road, shut off and roll-no vibe.

It really begins to vibe bad at about 3k rpm, foot off and i roll pretty smooth. Also when it shifts-the delay between the gears the vibe gets less but then picks back up again.

Im driving around in 4wd (well fwd)as I removed the rear driveshaft, its like I never even removed it-still vibrates the same-so that could possibly preclude the rear axleshaft I think..

you should really consider looking at the flex plate i have run in to this twice in the past can have hair line crack or maybe a ballancing weight spun off any the best of luck to you <img src="/forums/images/graemlins/patriot.gif" alt="" /> <img src="/forums/images/graemlins/patriot.gif" alt="" />

I thought you checked the left axle shaft when you found that the right one was bent. I don't think you need to replace it unless it has runout.

Does your rear diff make any noise?

Had a Chevy that did that to me. Harmonic balancer on the crank snout crapped out. The outer casting had shifted on the crank snout core. Racers with high output engines see that too. Anyway, mine was ok except in a rpm range of 3K to 3.5K. Drove me nuts. Racing buddy told me to swap it out and see if that was it. As you do not see the vibe while rolling not under power, that may be it.

What do you Toy experts think?

To follow up, can you put it in neutral and rev the engine up to 3k without vibration?

Since rolling at "vibrational speed" without the engine on produces no vibration, it seems unlikely that it's bearings or drive shafts. It's unlikely that it's the front end since you had the vibration with rear wheel drive and the front disengaged IIRC.

Is it RPM related? Is it at 3K regardless of which gear you are in? If it's RPM related, that would point heavily to pongoboy's suggestion of the flex plate or something similar.

Chip