Pleas help me diagnose my vibration

[CJM]

I know many of you are sick of hearing this, but im still trying. What I was wondering what everyones thoughts are here, cause im literally sick of my T100 but I cannot afford anything else really right now.

1996 T100 3.4L V6, auto, 4wd, x-cab.

Heres what happens:
If you take off you can feel a profound movement on the drivers side rear of the truck. Kinda like wheel hop I guess is best to describe. Once i get to about 20mph you can feel the vibration when on the gas.

At speed I can feel a vibe right under my feet, actually right where the cab mounts are but it also vibes the entire truck as I go too. On the gas only do I feel it, while coasting along its barely there if at all. Step on gas again and it comes back.

Here is what I have diagnosed/done:
-Replaced passenger side rear axle shaft-the vibration lessened to a degree.
-Replaced trans mount (rubber was worn and coming off but no effect)
-Checked motor mounts. Drivers side seems to be looser of the two. Both seem to have play in them more than I expect. I dont know how much is bad tho, but I can wiggle the drivers side a good 1/2 inch or more. I bought new ones but havent gotten around to installing them.
-Checked the cab mount bushings, all are worn out BAD and i bought new but dont have time to replace right now. Right under the drivers door I can push the mount back and forth a good 1/2 inch or better.
-Noticed this bushing that connects part of the front differential to the whole front suspension is FLAKING apart. Gonna replace that I guess if I can get it from toyota.
-Replaced all shocks with HD
-Checked vehicle with rear drive shaft disconnected and off, the vibe still existed in what equates to fwd, in all gears..maybe not as bad however. The rear still spins if the tires go. But in the air it seemed tohappen too with only the fronts going.
-Had both driveshafts checked and balanced, had the propeller shaft replaced. Didnt seem to help but eliminated them from being an issue.
-Front CVs seem fine, dont seem to be bent, nothings leaking out of them.
-Replaced all brakes, calipers, rotors, shoes, drums, and rear wheel cylinders.
-New tires and wheels balanced perfectly and re checked again to be sure.
-Front end seems to be loose despite new idler arm, pitman arm, and all balljoints, tie rods and centerlink are fine and have no play. New steering stabilizer too. I have a small side to side play and can hear a decent clack when i push the wheels forward and back.
-Motor seems tight as does trans, engine runs very well and trans shifts super smooth and good. Also the motor was totally redone about 60k ago by previous owner with receipts from toyota.
-You can watch the 4wd shifter wiggle back and forth as you take off. It wiggles quite a bit but I dont have anything to compare it too.
-Added these small helper springs that sit on top of the leaf pack and take up slack-seems to have lessened the vibration and wheel hop a bit. This seems to have had the best effect. I would assume after 200k my springs are worn out but enough to cause axle wrap this bad I doubt it. It was 400-600 bucks for them to rearch and rework my springs after i called 5 different places and i didnt do it cause of the cost.
-I cannot tell if the flexplate is bad in the trans but the engine and trans connection has no play it seems.

So thats where I am at, i am gonna install the mounts when i get a chance and take it from there. I am thinking the drivers side shaft (although it had the same amount of play the pass replaced side does)is no good and bent. It makes sense b/c of the wheel hop and vibe at speed in any gear and in fwd too b/c although its disconnected the shaft still turns as you move no?

I just dunno anymore, I wanted to buy a newer tundra but at 10K plus they are being sold for I cant afford it. I really love this truck but its getting to me.

[Seanz0rz]

do your engine mounts!

i hate to even suggest this, but is it possible the axle tube has separated from the spring perch? im not very familiar with the way your rear suspension is setup, but it sounds like a broken perch, while still being held together with the ubolts, could cause that kind of vibration and "wheel hop". maybe something to look into.

[Good Times]

Seems like all of the repairs you have performed to date has resolved some of your vibration but you haven't found the source. I'm not sure how you'd go about in figuring out the source but I'd say eliminating variables you have on your truck may help you out instead of just trying to replace everything on the truck that appears to be worn. Not sure if you have time but try this cuz I'm actually lost as to what could be wrong.

1. truck on stands (all of em)
2. remove both driveshafts
3. start engine and "pretend" you're driving and get your vehicle up to normal driving speed to see if you experience vibration.

If you experience vibration here then you know it has to do with something with your engine/tranny mounts or the engine and/or the drivetrain (tranny/transfer case)

If no vibration then we can immediately eliminate the mounts/engine/tranny/transfer case.

4. Add one driveshaft (rear)
5. Try again - get your truck up to normal driving speeds and see if vibes appear

If you get vibes then you know it's either the shaft or axle/tire. (rear) If no vibes then move on.

6. Add other driveshaft (front only - remove rear)
7. Try again - same thing here

If you get vibes then you know it's either the shaft or axle/tire (front)

If none... move on

8. Do it with both and see what happens

If you get vibes at this point then I'm stumped cuz it shouldn't since it had no problems when running separately. The only thing I can think of is something in the transfer case at that point?

If no vibes... move on

Now time for a test drive...

9. remove front driveshaft - drive

10. swap driveshaft - drive

It's gonna be a pita but at this point I dunno. I'm not a certified mechanic or anything just a garage junkie but I figure this should help ya out or something.

Good luck

[CJM]

All good ideas lance, but I cannot get the front shaft off b/c I need to remove the cross member for the trans and I cant get it off no matter how hard I try-the bolts are STUCK! Heat, penetrant oil, battery impact and a breake rbar witrh a cheater bar havent budged them. I may have to borrow a air impact gun somewhere along he line.

I checked the axle tubes and perches, good to go there.

[CJM]

Small update:
Talked to my mech today about the leaking seal in the axle shaft side he replaced. Seems its fine now, dont understand why its leaking. The shaft and whatnot seems to be true and no issues.

Also asked him to take a look and replace my motor mounts. I already bought them but I lack the time to do them. I only have off from work tues/thurs and its sweltering outside. Plus I feel bad for my mech, the guy has always done me good and now his biz is way to slow for him to even support himself while my job has really turned around. Speaking of which, alone in tips the other day I made over 100 bucks Thank god work has picked back up.

[Crinale]

you a server? i make about that on a good night shift serving here

[CJM]

you a server? i make about that on a good night shift serving here

I wish, I work for a roadside assistance company. Basically drive around and change peoples batteries, flat tires, unlock thier cars, etc. We mostly work for AAA as a contractor, hard work but i enjoy it.

If I did want to be a server, you wont make that kinda money around here unless your in a higher end restaurant.

[elripster]

Did you ever remove the front half shafts and take it for a test drive? I think I recall you had some issues trying to get them out.

Frank

[CJM]

I couldnt get the front drive shaft out itself, cannot remove that without dropping the trans a bit.

The front doesnt seem to have the vibration after ALOT of testing, it seems to be dependent on RPM range. Very low RPMs like crawling along does nothing, but give it gas to go and you can feel the rear drivers side rear axle wrap. When I take off I can physically feel this end lift up.

Also the vibration is right under the seat up front which coincidentally is where not only is some kinda bushing for the front suspension absolutely shot but also the cab mounts have alot of play. Also the motor mount on that side seems to be way looser and have alot more play than the other side.

I cannot discern if the front cv axles are warped, but front what I can tell when I had the truck going on jackstands and the front going they didnt look like they were spinning out of round-infact looked fine. Didnt try to remove them tho, but they dont spin at all on my truck when the hubs arent locked in.

I removed the rear driveshaft, the vibe still existed but not as bad. So I need to narrow it down to a few different things. Most of my issue is the fact I cant sit and play around, just dont have time.

[elripster]

If you removed the rear shaft, axle wrap is out.

So what you are saying is that you can get the vibration with the truck running but not moving? If it's the engine that would be the case.

Or, is it more like and engine load issue?

Frank