Is this a proper driveline test?

So trying to diagnose my vibration that goes away when put on 4 hi.

With the truck on the ground, in neutral and parking brake on, I grabbed the 1st piece of the drive shaft, between carrier bearing and transfer case, and I was able to move the entire drive shaft with about 1/8" of play. This play doesn't exist if put in park. Also with the truck In park and in 2wd, I was able to rotate the front prop shaft. However when rotated by hand, I could hear a metallic tap/ping sound from within the transfer case. Are these findings normal? Thx

 

I can't say for sure whether it's in/out along the drive shaft axis or if it's perpendicular to it.. the difference between those two movements is significant you say eh? I'll give it another go and confirm which direction the play is in.

However my thinking was, if a joint was bad, then even with the truck in Park, there should still be movement right? Everything is solid in Park.

 

When was the last time you lubricated the u-joints?

 

I bought the truck used 2 mos ago at 73K miles... When I greased her yesterday - The slip joints looked to be completely dry. The U-joint had black grease coming out when I put in new grease. No idea when it was last lubed though...

I ran out of grease yesterday and didn't get to lub

1) the front u-joint by the tranny
2) the double u joints by the carrier bearing
3) the slip joint on the front prop shaft

Given what has yet to be lubed, the vibration is still there when I drove it.. My last hope is after greasing the remaining zerks, that will cure the vibration, although I doubt it given that putting it into 4 hi ceases the vibration.

 

How fast are you doing when the vibration occurs ?
How fast are you going in 4WD - as fast as you are in 2WD?

Where do you feel the vibration most? Steering wheel? Floor boards? Front? Rear?

 

The vibration starts at 20mph and goes away at around 35mph.. although now the ceiling range is getting higher..

used to be only a rumblestrip type of vibration, with a frequency of about 1/2 - 1 sec. Recently, that symptom changed to sometimes being a constant rubbing type of vibrations. In all cases, the vibration can be felt thru the floorboard on the driver side (not sure about passenger side, never tested) and also be heard. It can also be felt thru the steering wheel albeit much less so than the floorboard. Tire is not rubbing because it doesn't matter if I'm turning or going straight.

Popping it into 4Hi takes away the vibration immediately. Putting it back to 2Hi results in the vibrations starting again. Putting into N and coasting thru that speed range makes no difference. An interesting observation - Say if the constant vibration hum develops, I can pop it into 4 Hi and then pop back out to 2HI and that vibration will then change into a rumblestrip type. It seems the act of engaging/disengaging 4WD has a direct effect on the vibration.

Actually, it looks like these guys have the same symptom as I'm experiencing.. And looks like so many Tundra ppl are experiencing it and it is a well known issue.. I'm surprised so little have been reported for Tacomas..

 

The only other thing I can guess...is something related to the actuation of the 4WD. Like....knowing the front axle shafts are always turning up front regardless - but as soon as a 'force' (from t-case) is added...the vibration goes away.

I wonder if there's a way to disconnect the actuation (vaccuum?) of the front diff...... to prevent it from actually engaging into 4WD at the diff. Then...put it in 4WD and see what you get.

If you shift it into 4WD and you get the same symptoms as in 2WD...then I'd say there's something going on inside diff/actuator area where the engagement occurs.

That's my only other 'thought'......

 

So when in 2WD mode, does the front prop shaft (from tranny to transfer case) turn? I assume not right?

 

I would tend to believe also - that it should not be turning while in 2WD.

The axle shafts at each wheel will be turning all the time, they're just not 'driven' in 2WD.

The other thought I had....if you have a problem in the transfer case. If you disconnected the front prop shaft and put it in 4WD, what result would you get?

 

so in 2wd, the front prop shaft should be free to move as it is so on my truck while it's in Park. So even while driving down the road, the front prop shaft is free to rotate and not locked? Can someone confirm this?

Okay so say I'm driving down the road in 2WD, with the transfer case shifter in the 4Hi position, can I push the transfer case lever to Neutral?