OK guys, one of those difficult questions or maybe not so difficult, but here we go.

I've got a vibration in the driveline. I've had it for a while, but seems to be getting worse somewhat. Maybe I am just noticing it more now that I got a set of street tires on it instead of my loud rumbling M/T's. I don't seem to feel it though the steering wheel and if I had to describe it, it's more of a grumble or groan along with a vibration. But I know everyone's groan grumbles etc etc are different.

I would take a video but with ever other squeak, noise etc etc in the cab, not sure the cam would pick it up or not.

Anyway,

When it happens: slightly on the throttle & slightly off the throttle. Meaning pushing on the pedal and releasing pedal when the throttle is only slightly open. Might be there as well when throttle closed rolling but not really noticeable. Hubs unlocked and t-case in 2wd. 4th & 5th gear.

When it doesn't happen: Clutch in rolling down highway & Slow speeds.

What I have not tested: Hubs locked & t-case n 4wd. 3rd gear on highway.


Now I am not sure if it's a t-case, trans mount, u-joints or maybe pinion angle due to flat springs, or the rear diff. Doubtful its a motor mount since it doesn't seem to happen at slow speeds and gving more throttle makes it go away. And it's almost unnoticeable when throttle is closed.

Not sure how to test anything driveline related other than wiggling the u-joints. Is it possible for a driveshaft out of phase to cause these symptoms? Maybe it's been there since my rebuild a year ago just not sure and I had the D-Shafts out during the rebuild and my dumbass didn't mark them and I don't like my 25% chance of getting it right. Hahaha.

 

I had the same prolem, slight on/off accel vib. I replaced u joints and several other things. In the end I found the driveshaft flange (companion flange) on the back of the transfer case loose. I tightened it up to 87ft/lbs, about an 1/8th of a turn, restaked the nut and all vibs were gone. When I say loose I mean in nuetral and p-brake on the flage would wiggle. Hope this helps.

 

hmmm, I did notice yesterday some gear oil around that flange on the body but no obvious leak. Thanks, that will be the first thing I check tomorrow while I am under there. Do you remember off hand what the size of that nut is?

 

30 mm newbie

I'd check u joints

:wabbit2:

 

I used a 30mm socket, it seemed a little loose, but it got the job done.

 

Damn now I got to buy another $20 socket. lol.

I got a spare driveshaft, I might try that too. Hopefully it fits, I have yet to stick it on the truck since I bought it a year ago. For $20 I didn't care if it fit or not. haha.

 

Tcase and pinion nuts all 30mm so it's a good investment.

:wabbit2:

 

yeah I hear that. IIRC Harbor Freight I think had one as well. I was just up there twice in the past week too. haha.

 

30mm short or deep? Assuming short is fine. Napa has to order it for me but they are only like $8-11.

 

6 point 1/2" drive deep 30mm

Impact socket is too thick. Normal socket.

:wabbit2:

 

thx wabbit, almost ordered the 30mm short impact. Looking on 4crawlers site couldn't tell all but regular socket was used.

Dang napa and autozone both have 12pt. I guess that would work, but something that big I always like to use the 6pt as well. $15 at napa $20 at autozone which has it in stock.

In stock, looks to be 6pt regular but black oxide finish, no mention of impact. $14.75. http://shop.advanceautoparts.com/web...|GRP2062_____#

Use with 1/2" drive ratchet, breaker bar or torque wrench

 

Xtremme, I had the same problem, loose flange I replaced the seal and got a new nut from Toyota it quieted the vibe a little. Then I put the truck on a hoist and chained it down and while idling in 4th gear, I noticed my rear driveshaft had a little hop to it. Took it in and had it fixed and everything is smooth, no more shifter vibe in 4th or 5th gear. Im not saying your driveline is bent but take a look. Hope this helps somebody. I spent 400 bucks chasing the problem. Now I know to start at the cheapest part first

 

I've got several but 12 point rounds off old worn stuff, shorties are just short and impact too fat to fit. Only several places you need it like I said, but worth it for when needed.

Kinda like the 54mm or 2 1/8" socket. I got a good one so when I need it, I got it and I can put it on my torque wrench.

If I need a tool once, I'll need it again on another Toyota so I buy it.

If all your problems look like a nail, then all you need is a hammer.

:wabbit2:

 

Right now as it sits, I am either leaning towards that loose t-case flange since there is evidence of a leak or the pinion angle is a little messed up due to the spring sag. Possibly the pinion flange as that leaks too, but that might be because of a stuck breather valve.

But I do have that spare driveshaft in case this one happens to be bent. Crossing figures it's the right length. I believe it came off of a single cab 94ish pickup.

 

Oh and wabbit, the nail and hammer reference is probably not a good thing for me, I've been known to use adjustable and socket wrenches as hammers.

 

Note that a tight (non-wiggling) u-joint doesn't mean its not bad. I had a driveline vibe on my 4runner and took the driveshaft off to get it balanced, the rear ujoint was seized and the spider was actually cracked. i'm convinced this was my main vibration - but got the driveshaft balanced anyway. also, at the same time noticed the flange nut on the tranny propeller was loose - so did all 3 things and running smooth now.

 

Well gonna try one thing at a time, the companion flange nut on the t-case was in fact loose and leaking. Didn't replace the seal as they weren't available right away from the local auto parts stores. Re-tightened to FSM 90ft-lb. If it doesn't stop the leak or it starts to leak again, I will replace the seal. If it doesn't fix the vibration, I am gonna put that other driveshaft in. If that doesn't work then I am gonna look into the rear pinion nut. But afraid of that thing because there is a big range for torque specs on that and don't want to over tighten it. But doesn't seem to have alot of play in it with the front of the shaft disconnected from the t-case. Not sure on how much backlash I am supposed to have but there is some.

Now just to give it a test drive. And go from there. I don't like doing multiple things at once so.....

 

Vibration is still there, can't really tell if it's less noticeable or not, but it's still there. So onto the driveshaft. But not today.

 

I don't know if this has anything to do with it or not or if it's possible now that I am thinking about it again, but I measured the distances between the top and bottoms of the flanges, I came up with 45 1/8" on the bottom and 45 1/4" on the top. Now this truck has factory flat springs and shackles which leads me to believe flat springs can cause pinion angle issues?

I have not actually checked the angles yet as 4crawler mentions and don't want to do the trig work to figure out exactly what the angle difference is.

 

small update, greased the drivehsaft stuff and the vibs seem to be gone. But I also put 6" shackles and 2" springs on. So not sure if pinion angle did it or not as I don't know what it feels like with a bad pinion angle. If it comes back I will know it's something in the driveshaft. (u-joints)