Checked the FSM further and found that the transfer case bearings are not shown in the main exploded view. There is a ball bearing in the extention housing. There is also a roller bearing in the rear chain case.

I will try to pull the driveshaft tonight and check the output flange tightness.

Has anyone replaced the bearing in the extension housing? The Toyota manual says it can only be replaced with the housing. That probably means it is an expensive assembly from Toyota. Maybe it can be found in the aftermarket from say Transtec or Transtar that handle standard A340H transmission parts.

 

I pulled the driveshaft off at the transfer case and it looks like the vibration may be caused by a loose transfer case output flange. The nut holding the flange was not even finger tight. It was only held in place by the stake. I'll go to the dealer tomorrow and pick up a new nut. The threads on the old nut are not too good and the area around the stake chipped away when I tried to remove it. The output shaft looks ok. I'll post an update when I put it back together tomorrow.

 

http://www.vibratesoftware.com/

Good Info!!!

 

Retorqued the t-case flange nut last night and put the driveshaft back in. Yeah, the vibration and noise is gone on the highway. Also looks like the bearing at the back of the case is still ok. I'm really surprised the fix was so easy since it has been going on for a year or so (oops). I haven't checked the flange angles yet (haven't found my angle gage).


SurgeGT,

Any update? FYI, you might have more luck find anything loose around the driveshaft if you have the truck on level ground, place the trans in neutral, and block the front wheels. I think some of my problem with an earlier investigation was the tranmission being locked in park and a slight driveway angle placing load on the driveshaft. Maybe...

 

No need for and angle gauge, a simple tape measure works just as well:

http://www.4crawler.com/4x4/CheapTri...n-Measurements

 

I read about your tape measure method, but I bought a cheap angle gage a few years ago to do this (when I ran 6" lift rear springs). The problem is my wife re-arranged the garage and I can't find the gage. I'll get it tonight and check...

 

Ok since you guys are on the subject. I have developed a nasty vibration all of a sudden. I have no lift and have not changed anything to the driveline or suspension. This vibration appeared 1/2 way to work this morning. Can you give me a run down of things to check and how to check them i.e u-joints (how do you check them out, what method). The vibration can be described as bad when starting off or whenever under a load (going up hill), bad at low RPM, better but still there at high RPM (speed is not a factor), and still there but faint when coasting. It is definitly something to do with the driveline, because I can push the clutch in and it subsides but if I let the clutch out it comes right back and is very prevelent under load. I am leaning to u-joints or center bearing, but would like a check list and how to, if someone could help out.

 

Short list of causes: u-joints, center bearing, pinion/t-case flanges, or t-case mounts.

I would recommend parking on level ground, block the front wheel(s), place the trans in neutral and start pulling on the different parts in different directions. It only takes a few minutes of inspection. Also look for things like missing or loose bolts on the flanges, mounts, etc.