Bad Motor mounts...drivetrain not aligned?

[Asmoday]

Hello all,

So while under the M1009 yesterday to replace a speedo cable and front emergency brake cable I decided to take a look at the trans mount bushings on the cross member for the trans/transfer case. Ever since purchasing the vehicle last November I have noticed a clunk when I drive over a certain king of bump or dip in the road. I originally thought the transfer case was hitting some carriage bolts that where hanging down into the trans tunnel area from whatever the army mounted there at some point and after removing them a while back the clunk got better but was still there.

So after checking the mounting pads on the cross-member and deducing everything looked fine I started looking elsewhere and behold I found the issue...

The transfer case is hitting the trans tunnel. The upper right portion of the the transfer case above the speedo drive assembly is actually resting on the sheet metal of the tunnel. There is a portion of the transfer case that looks like a little step and it's laying right against the tunnel floor.

I have attached a pic with a arrow showing the contact area...

After looking closely at the drive train underneath it looks like the whole drive train is shifted to the right somewhat.

Where should I begin to try and fix this issue?

I was getting ready to do motor and trans mounts anyway so maybe that's a start.

 

[86m1028]

Could be bad trans mount and or motor mounts.
Also look at your body mounts, if they are bad the body could have shifted or dropped down.
Has the blazer been hit ? Frame bent ?

 

[Asmoday]

Not sure on how to check the body mounts but everything seems to fit correctly. Doors fits and close correctly and body lines look correct...

As far as I can tell the truck has never been hit. The underside of the frame looks good and the truck drives and tracks correctly. I looked the underside over real well and could not see anything out of the ordinary.

I did notice that not only does the drive-train look like it's slightly shifted to the right in its alignment....it also is sagging on the right side like the right side trans and motor mounts have collapsed somewhat.

The motor mounts visually look ok but something is obviously off....???

 

[wayne pick]

Checking a broken mount visually is hard to do. The best way to check for a broken mount is to place a jack under the engine and jack up slightly to see if there is any movement. use a short piece of 2x4 in between the jack and the oil pan so you don't damage it. If there is no movement and while you have the engine slightly raised, loosen the trans mount bolts and try to push the transfer case back into alignment, a small scissor or bottle jack between the frame and driveshaft yoke is your best bet. Oh i forgot, check the long motor mount bolt on both mounts and make sure the nut has not come off causing the bolt to back out of the upper half of the engine mount bracket. That will cause big time movement.

 

[czechers1999]

My transfer case does the same thing. it hits the tunnel in the same place. it mostly happens under hard acceleration from a standstill. No clunking while driving tho. i actually bent the tunnel up just a shade and that helped a bunch. my motor mts are good. my transmission mount may need to be replaced.