Hello,


I wish my first post could be better, but I am in need of some help from more knowledgable people than I.


I bought a 2000 Ex PSD 4x4 in september. I have refreshed the suspension in the last 4 months; leafs, shocks, etc. I developed a vibration over 50mph after I installed the suspension and have been chasing it since.


I have replaced the U Joints, professionally balanced and lubed driveshaft twice, adjusted driveshaft angle to less than 1*, replaced the flanges for the TC output and the driveshaft companion flange. I have not touched the diff, but there is no decernable play in the pinion or leaks. Also, I removed the rear housing of the TC and replaced the output needle bearing and seal 2 weeks ago.


The output of the TC still has 1/4" play and a clicking noise coming just forward of the chain section of the TC. I assume the play is coming from other bearings on the main shaft in the TC.


I am about to purchase a remanufactured TC, but before I do, I need a reality check. Is it possible there is damage to the output bearing of the Transmission or something else?


I don't want to buy a TC to put in and experience a TC failure again in a short time. It doesn't make sense to me that there would still be so much play after changing the output shaft needle bearing of the TC if the TC main shaft is supported not just from the TC bearings but the output of the transmission unless there was possible play in the output of the transmission.


Thanks!

 

The transmission output shaft is supported by bushings in the rear of the case and the input of the transfer case is supported by a ball bearing within the housing. I don't think the issue would be with these. The main shaft of the transfer case is "two piece" and contains a planetary gear assembly to provide the low range gear reduction and couples to provide the high range. This assembly would be in the area just before the drive gear for the chain and could be the trouble spot.
Here is a pdf with illustrations. Transfer Case .pdf

 

Thank you, I misunderstood the main shaft is two piece, that make a lot of sense what I am feeling.

Well, off to get a rebuild.

 

Roland,
Thank you for posting the transfer case drawing. A picture communicates where words just don't do it. The sheer number of pieces in the case shows how complicated the t.c. is inside. And it can handle the torque of the 7.3--that is amazing!
Larry

 

So a bit followup.


I am a bit frustrated now. I replaced the transfer case yesterday and I am still getting vibrations at 50mph+. But now I get this buzzing and low droning sound in the cab at idle and it vibrates the whole truck until I start moving, where the buzzing and low drone goes away, but the vibration can be slightly felt when moving but coasting. At idle, it is a high frequency vibration and is felt in the seat and if something is put on the dash it starts buzzing.


Wondered if this vibration and buzzing is realted to the transmission mount? I wonder if the droning at idle may be related to the exhaust downpipe might be leaking now (had to mess with the exhaust while trying to get the tranny to TCase bolts out). Exhaust is MBRP 4"


Thoughts?


Thanks ahead of time.

 

Make sure your exhaust isn't touching anything. With a 4" there is not a lot of room between it and other certain things, leaf spring hangers being one, especially since you told us you had to mess with your exhaust.

When you go to move the exhaust could move just enough to pull it off whatever it is touching.

 

Sounds like exhaust to me as well.

 

Thanks for the help. I looked around some more and found that the heat shield had gotten stuck on the lip of the tranny pan and kinked it up. Just spent an hour bending things back in shape and all is well, the buzz and low drone is gone.

Now I need to figure out why I'm still getting vibration now that I have changed the transfer case for a new one, as well as completely rebuilding and balancing the driveshaft and getting the driveshaft angles to almost 1 degree of each other. Guessing the next thing to check is the rear diff?

 

Does the noise go away when you lift off the skinny pedal? My carrier bearing in my rear end went a couple of years ago and this was one of the symptoms. I pulled the fill plug and could see where the bearings had been delaminating, it was covered in stuff that looked like silver never seize. I also chocked the front wheels and put the rear on jack stands. Once I put it in gear and walked back there it was obvious there was a problem!

Oh and make sure to stop the rear wheels before throwing it into park (kind of deceiving when you are not moving) the parking pawl makes a hell of a racket if you forget, ask me how I know!

 

Thanks for the ideas, but I have no carrier bearing to deal with. Noise reduces when letting off gas, but still there.

I'm planning to lift the rear up and do what you mentioned to see if the diff is the issue. Don't know what else it could be other than the diff.

 

Sorry my bad, pinion bearing, not carrier bearing.......

 

Good question, but I can't feel any play in the pinion when it's in neutral. I'll double check and see what might be going on with it.