Transfer Case Vibration Issue

[loveofjazz]

My rig has developed a shimmy/vibration in second gear. It starts as soon as I shift into 2nd and accelerate. It goes away once the RPM's go up a bit (no tach on board, so I have to guess at 1500-2000 RPM's). I don't have any vibration issues in 1st, 3rd, 4th or 5th gear...just 2nd gear.

Thought it might be a u-joint on the intermediate shaft. Further inspection showed the rear u-joint on the intermediate shaft had a little movement, though not much. Had a friend look it over. He said the same thing. Slight movement detected at the rear u-joint.

Went wheeling -before- I swapped the u-joints and part of the shimmy went by the wayside. Swapped intermediate shaft u-joints before my most recent wheeling trip and the problem still exists. Seems like the first wheeling trip did more to alleviate the vibration than the actual repair.

While changing the oil on Saturday, I crawled around underneath and noticed the long arm on my transfer case was twisted at the rear mount. I can't tell if I parked it on a rock to do that, but I don't believe so. I'm going to look through my spare parts bin and see if I have another transfer case arm in better condition. I'd like to swap it out to see if it helps at all.

I know asking 10 guys will get 12 different answers, but I'm a bit stumped. Am I missing anything?

[fart box]

mine does the same thing and i haven't been able to pin it down either,

i'll post up what i find thats causing mine if i find it before you find yours, its probably the same thing, my u-joints are tight though and neither of my t-case arms appear bent or distorted, and mounts are good if not a little squishy

[loveofjazz]

I poked, prodded & pried at the t-case bushings. No issues there. No separation. All bolts tight. I'll probably throw some pics up here in a little bit. That twisted long arm had me a bit confused, though I don't believe it's the issue.

Mine used to shimmy so bad that heavy acceleration in 2nd created enough vibration once to knock the t-case shifter out of gear. Has yours done that too, fart box?

[beekiller]

Jim, a bent arm, however slight, can produce some pretty nasty vibes.  Replace it, then if ya still got vibes replace the ujoints.  They can give you vibes too, and you most def want good ujoints in there since failure will ruin the shaft.   


Or it could be your rig is telling you she wants to wheel more.   

[loveofjazz]

Jim, a bent arm, however slight, can produce some pretty nasty vibes.  Replace it, then if ya still got vibes replace the ujoints.  They can give you vibes too, and you most def want good ujoints in there since failure will ruin the shaft.   

Intermediate u-joints have been replaced. Did that the night before our last trip to Uwharrie. I'll post those pics of my set up in a little bit.

I'll be rummaging through what I have. Hopefully I've got a replacement part.

Or it could be your rig is telling you she wants to wheel more.   

She tells me that all the time. Look a good wife, she never hesitates to let me know that she should be on the trails climbing rocks, not on asphalt running errands. 

[fart box]

mine has only knocked it out of 4lo when i've been into the skinny pedal...HARD

[Surly]

I gave away two or three sets of stock t-case arms when I cleaned out my garage. I'm not sure if you or Ben got them, but one of you has spares laying around in a box.     Also, check the driver's side motor mount and the rear transmission mount. They're both prone to tearing, and will cause intermittent vibration issues when they do.  HTH

[Freebird01]

jim i would be very suspect of the t-case arms....both long and short. pull the case and compare those arms to some known good ones. i chased a similar vibe forever due to bent arms.

the short arm could be bent and you just cant visually see it right away from underneath. i actually bent my short arm about 1/2" and it didnt look much different.

also look at your transmission mount. it will cause vibes and is often overlooked.

but i would say tcase arms if you didnt have it before....make sure you check out the frame mounts as well.

what gears are you running in the diffs and tcase?

[loveofjazz]

mine has only knocked it out of 4lo when i've been into the skinny pedal...HARD

Yeah...the time it knocked the t-case out of gear, I was accelerating hard and turning to the left. I was on pavement, though.

I gave away two or three sets of stock t-case arms when I cleaned out my garage. I'm not sure if you or Ben got them, but one of you has spares laying around in a box. 

That's exactly where I was checking next. I re-organized my shelves recently. I looked on the shelves just to be sure when I got back in a few minutes ago but had nothing there.

Also, check the driver's side motor mount and the rear transmission mount. They're both prone to tearing, and will cause intermittent vibration issues when they do.  HTH

This does help, Ken. More than you realize. I hadn't even thought of either of those locations.

jim i would be very suspect of the t-case arms....both long and short. pull the case and compare those arms to some known good ones. i chased a similar vibe forever due to bent arms.

the short arm could be bent and you just cant visually see it right away from underneath. i actually bent my short arm about 1/2" and it didnt look much different.

also look at your transmission mount. it will cause vibes and is often overlooked.

but i would say tcase arms if you didnt have it before....make sure you check out the frame mounts as well.

what gears are you running in the diffs and tcase?

I'm running stock diff gears currently and 4.16's in the transfer case, Jason.
What "frame mounts" are you talking about? Do you mean where each transfer case arm mounts to the frame?  (I get confused easy, man...you know this. )

[Freebird01]

What "frame mounts" are you talking about? Do you mean where each transfer case arm mounts to the frame?  (I get confused easy, man...you know this. )

that's exactly where in talking about. the tower for the short arm can bend pretty easy. so can the rear most mount on the long arm. it doesn't sound like you got enough gearing going there to bend the frame mounts but you could very well have bent the long arm with just beating on it. you don't really have to park it on a rock to bend those.

[loveofjazz]

That long arm is bent. I'll post a pic a little later. It's kind of twisted.

[Freebird01]

That long arm is bent. I'll post a pic a little later. It's kind of twisted.

thats probably your culprit then

[fart box]

ill have to recheck my arms tonite, good thing i have a set of strengthened arms waiting to go in, if they are bent

[loveofjazz]

ill have to recheck my arms tonite, good thing i have a set of strengthened arms waiting to go in, if they are bent

Ain't it funny how we don't replace stuff until we absolutely need to?
When customers leave me alone for the day, I'll post a pic or two.

[Lizooki]

I think it's a loose screw behind the steering wheel. 

 

*Check the bolts on the tcase arms themselves.( arms to case)
*Tranny ( hee hee, I said tranny ) mount.
*Drivers side engine mount.
Uneven tire pressure.
Fat dude driving ... skinny chick ridin'.
Long floppy Fang-O-Death shackles.
Bad shocks.

Confused yet?

U-joints. PULL THE SHAFTS TO CHECK! I have tight ones explode the next day.

The ones with trhe asterisks are the 1st choices.