Hey all- I've been doing some of my own work on my '93 22re Toyota pickup and I'm trying to diagnose/solve a problem I'm having with the 4x4. When driving at speeds higher than 25mph in 4 high I have a severe shake, and I can't figure out where it's coming from. I'm going to list some of the things I've done/had done to the truck since I've encountered the problem as I've eliminated these as issues:

• Tires are less than one year old and balanced.
• Wheel bearings have been done in the last year
• U-joint and front axle shaft were replaced last year
• Replaced locking hub mechanism (one hub was extremely difficult to turn, but when replaced shake remains)

Some folks have mentioned steering box, but I'm looking for anything else obvious I should be checking/replacing on an older truck that might cause the severe shake. For what it's worth, the 4x4 actually does engage and I can drive it well in the snow, I just can't drive it faster than 25mph without the shake.
Any tips, tricks, and helpful "how to videos" strongly encouraged! Thanks y'all.

 

Wiggle your front axles. Play? At the diff?
Is the truck lifted?
Last alignment?

You shouldn't be driving in 4 high on road anyhow.

 

This was the symptom in my '85 pickup when the problem turned out to be the splines in the front drive shaft slip yoke were all buggered up. You could rotate the two halves of the shaft a good amount, maybe 1/4 turn or so, independently.

 

On deep snow? Or road?

Since we don't have a "center differential," driving in 4wd on a non-slippery surface (a road) will usually lead to slight binding between front and rear axles, which I feel as a "shake."

 

Hey all, thanks for your input. Yes, I understand that driving in 4x4 on dry pavement isn't what it's designed for- this shake has been continuous since last winter in Colorado where we did have a lot of deep snow. I'm trying to get things working properly before the snow flies again... so currently while I'm working on it the only surfaces I have to "test" it now are dirt roads and pavement.

OldBlueMidnight- are you referring to the splines that the locking mechanism lines up with in the hub housing? The new locking hubs I installed seemed to line up and turn together well. I did read up on greasing the splines, but I'm assuming that they might be located further into truck? Where exactly should I be looking to test their rotation? Thanks again for the advice!

ev13wt- The truck is lifted and has a little loose-ness when driving in regular 2-wheel, but that's something I'm pretty used to. The 4x4 shakes hard, a significant difference from 2 wheel. It also shakes hard in 2 wheel when the hubs are locked. Alignment was done last year with new tires.

 

Sounds to me like an unbalanced front drive shaft, or a bad u-joint. It's a bit of work, but try pulling off the front drive shaft and driving at speed in 4wd. That will tell you if the drive shaft is part of the problem. If the problem goes away, take the driveshaft to a driveline shop and have them inspect it.

Also look at the bearing on the front output shaft of the tcase. Check it for radial play. Shouldn't be more than .002-.003".

 

I'm referring to the splines in the slip yoke of driveshaft connecting the transfer case to the front differential--see attached photo, I've placed a wire handle on the slip yoke. I'm with RJR as far as how to eliminate driveshaft as the culprit. Could be the slip yoke, could be balance, could be U-Joints (U-joint problems are probably the most common). If problem persists with driveshaft out and hubs locked, the problem is in the front diff / axle, but it sounds like you've replaced most of what can go wrong up there. Also, if problem only happens in 4H and not at the same speed (25 mph) in 4L, then I don't think it is the axle or driveshaft. That would have to be a problem with the t-case I think.

 

I am with the others on this, it is most likely your front driveshaft.
When you say "I have a sever shake" is the steering wheel shaking or are you feeling it through the seat (with your assometer)?
I can tell you right now the steering box IS NOT the cause of your shaking. If there is too much play in your steering box (there HAS to be SOME) it will allow more shaking, but it is originating elsewhere and it would be all the time not just when you have the hubs locked in.

 

What does the vibration sound like? At 25 mph the wheels are rotating about 4 times/second, so a wheel related problem is more of a thump-thump-thump-thump kind of noise than a "hmmmmm" (unless it's a bearing going out, but you've replaced those. Bearings sound more like a growl, without a lot of shake.) The drive shaft is rotating 16-20 times/second, so problems with it will be heard more as an actual vibration.