TRunner

I know this whole vibration thing gets covered all the time and I have been involved in many of the threads. Especially since my last encounter with the drive shaft falling out due to the front u-joint busting. But I still have some vibration and it is getting worse. I took it by a shop after I replaced the front oil seal on the pinion and replaced the drive shaft to make sure I did everything correctly. I am not sure how well they checked it out, but they claim everything seemed well, except the seal where there pinion meets the differential. They tightened all those bolts and it barely weeps now. This was only a couple months back.

Now when I was driving home from work yesterday, it stuttered like the engine stalled, but it felt like I hit something. This was quick. A second at most. Then it happened again and would not maintain 65mph with out a lot of shaking. I was exiting the freeway anyways and once I got it to city driving, it seemed fine again. Well it started happening on my way to work again today, about 30 minutes into my drive again. It doesn't seem to do this until I have been maintaining a high speed for a while.

Anything to do with gears is where I fall ignorant, so as far as I know this could be differential, rear axle, transfer case, or transmission. Anyone tell me what I should do to track this down? This one may end up in a shop as I would hate to take out my daily driver by screwing up my drive train. Any advise will help. Thanks!

TRunner

HELLO? Someone wanna pipe in here before I have to try and make it back home in this thing. I don't think it is going to make it....

TRunner

dang it... I leave in ten minutes for another 30 minute plus drive home. Wish me luck at least fellas!

FilthyRich

good luck. Be safe....

naksukow

I would pull both drive shafts and take them to the best drive shaft shop around you. have them balance them for you. I would also order new toyota hardwear and make sure you torque ever thing to spec. Do you still have the vibration dampner on your transfer case?

This is assuming that your tires are balanced...

4Crawler

iTrader: (3)

Check the rear pinion flange for play. There should be no play up-down or side-side. Not uncommon for it to be shaken loose by other driveline vibrations. Sure, you may have fixed some/all of the other issues, but the loose flange can now cause problems. A 30mm socket to tighten the nut may help if the pinion bearings have not been damaged. Also check the balance and phasing on the rear shaft:

http://www.4crawler.com/4x4/CheapTri....shtml#Phasing

TRunner

Tires should be good, I have been keeping up with them rather well, but they are still a bit cupped from when my alignment was screwed up.
The dampener is still there.
I should probably balance the drive shaft.
What hardware you talking about?

TRunner

The pinion flange was loose once before and I tightened it, but it may need it again. It took a hard jolt when the front of the drive shaft landed on the pavement doing 70mph. The bearings seemed fine and I did replace the oil seal, but how do you set the torque on the nut? I couldn't ever get the preload and setting it back to where it was made it real lose, so I tightened it some more until it quit having play. I guess I will pull the rear shaft and have it balanced and phased for safe keeping.

BTW which way should the u joints be in relation to each other? lined up on the closer "u" or off by 90 degrees?

leiniesred

U-Joints need to be in phase. That means the SAME on both ends. inner "u"s should be the same. If they are not, and are off by only 1 spline, you would get vibrations.

I think you gave away the problem in the last post, Ted. When the front of the driveshaft dropped down to the pavement, it jammed back against the rear pinion thereby compressing the crush sleeve on the pinion shaft a little more. This allows your pinion bearing pre-load to drop to 0 and you have a wobbly pinion shaft. The shaft wobbled and wore out the seal which caused the leak. (that's bad!) you fixed the leak (that's good) but even after tightening the pinion nut, you can't get the preload back on the bearings again. It is possible for the pinion to "walk" deeper into the diff eventually contacting the carrier in extreme cases. (that's bad) either way, there may be gear damage from the loose pinion shaft. Hopefully that isn't the give 'n' go you are feeling.

So:
First, throw bod under truck and check the phase of your u-joints. You may be surprised that they are off a spline (or 2). if that doesn't fix it, then that shaft is probably bent from when the front u-joint broke. take it to a good driveshaft shop. They can check it out and retube if required. (always wanted a heavy duty DS didn't you?)

While the truck is down for the count and the DS is at the shop, think about pulling that rear diff and at least replacing the crush sleeve or switch to a solid spacer while you inspect the gears for damage. (I think you'll be OK).

I know it is a lot, but these are only suggestions, you don't have to do any of it

TRunner

Great post!!!

I already replaced the drive shaft with one from a junk yard, so it should be straight, but I plan on having it checked after I get the lose flanges tended to. I am waiting on a retainer clip for the rear bearing near the output flange of the transfer case. Nobody in the US has it, so I wait for the backorder to come through. After i get that back together, I need to dive into the differential, but I don't know squat about those, so it should be a good learning experience. Some questions, though:

How do I know how tight I should tighten the pinion nut? I don't follow all this preload stuff.

Also, when you mean the u-joints should bee the same do you mean like this:
]---[ (where the "u"s on the drive shaft are at the same angle making the assembled u-joints mirror images about the drive shaft)
or
]---~ (where the "u"s on the drive shaft are 90 deg. off making the whole assembled u-joints the same from front to back)

Beartracker

I would like to know how tight the pinion nut should be for my 01, 2.7, 4x4 Tacoma but I can't seem to get an answer from anyone on that either.
Sure hope you get yours fixed. Mike

4Crawler

iTrader: (3)

There is not really a torque, per se. If re-using the old nut, tighten it back down to the same place it was prior to removal (use the stake mark as a reference). Short of that, what I use is no more than 90 ft-lb to snug it up tight. Why 90? Well, 135 is the torque used for setting the pinion bearing pre-load with the crush sleeve (assuming that one was used vs. a solid spacer). So 90 is about 2/3 of the torque needed to alter the crush sleeve so seems the be "safe". Also, the exact same size nut on the transfer case flange is also torqued to 90 ft.lbs. And don't forget to unstake the nut prior to tightening it and re-staking it when finished:




I snugged up my old crush sleeve pinion a few times when it would loosen a bit. I now run solid spacers in both my diffs. and don't have to worry about that.

TRunner

90!? OMG!

When I put mine back to the same location, it had way too much slop. You could move the flange around more then 1/8" so I snugged it up until it could be moved around by hand (not turned, but moved around like vibrations would do). So I imagine I am about 20 ft-lbs or so. Good GOD! That might be my vibration problem still. I get to play with it this weekend again, so we will see.

leiniesred

Ted: Like your first ASCII art picture. The flanges are pretty soft material and tend to wear out faster than the shafts. (that's good, cause the are a lot easier to replace.)
I doubt, however, that the splines on the shaft are the problem. It is going to be tough to try to reset the pinion bearing preload without taking things apart. an option is to find the fancy pants tools or a person who has em to pull the front bearing off the pinion and then schange out the crush sleave. Now, setting the pinion pre-load on the truck is going to be even harder because you will only be able to measure the bearing preload in the tiny range of the backlash (about 1/8 of an inch on the pinion)

It might be easier to simply yank the entire diff and take it all apart on the bench.

What is all this preload crap? Well, bearings kinda like to have something to do all of the time. They spin better with little load on 'em and the shaft doesn't wobble around as much (If you can feel it wobble around, it is WAY too loose) preload is this little bit of load. In the case of used toyota v6 pinion bearings, were talking about 3-4 INCH pounds of torque required to spin the pinion shaft. (that's not a lot!)

If that were my truck, I would take it all apart, but if I had to drive it tomorrow, I would try to very carefully snug down the pinion nut until I could just FEEL a difference in how hard it is to crank the pinion shaft back and forth in the tiny amount of space afforded in the gear backlash. If you set that preload too tight, you will burn up the bearings and smoke the diff.

There was a guy on a jaguar site with a writeup on how he reset the pinion preload on his jag or ford-uar (I don't know what model it was) without diving into the diff.
I can't find the link, but here is what TIMKEN (inventor of the tapered roller bearing) has to say about the advantages of SLIGHT bearing preload.

http://www.timken.com/products/beari...Fs/Vol5No4.pdf

TRunner

GREAT STUFF!!! Thanks for posting!

4Crawler

iTrader: (3)

I did a pinion seal/flange replacement writeup:

http://www.4crawler.com/4x4/CheapTri...eal/index.html

Ironmike4x4

I don't know the specs for a Toyota but if you have a beam style torque wrench for an old nut on GMs only it should read around 15-20 ft/lbs. before the u joint starts to rotate. Make sure you read it while its turning and not the start of the turn. Find out what the spec should be w/ an FSM. If it falls below the spec then tighten the nut more.