Vibration/shaking at @1500 under boost.

Only under large boost/high power gives some clues. Slipping clutch? Smell burnt afterwards? Torsional twist? More power, more twist. Check motor/trans mounting and for body contact.

 

The plug swap john referred to is getting an extra drain plug so you can check for metal on the magnets without draining the trans and rears

 

Someone mentioned greasing the throw out bearing "a lot" I've always been told a pump or two is plenty that to much grease is worse than no grease. Not to mention all that extra grease will get thrown around in the housing and make a mess. Any thoughts on that. I've always been a believer that to much grease on certain things is bad.

 

I was going to comment on this also, but had decided to leave it alone as John, as an old and experienced hand is usually spot on with his advice. Maybe he will come back in to explain this. Most places extra grease isn't a big problem, but that bearing is pretty small and should only need a couple shots periodically, I usually do mine at oil change time. Too much grease in there and you risk getting it in the clutch itself, not too mention a pile of it down in the bell housing. Right John P?

 

I run a '13 4900ex glider. Same issue. I was told it has to do with the engine mounts. My truck only has two engine mounts up front. The tranny holds the back of the engine up and in place, if that makes sense. I would think having less support at the bell housing would allow a little more movement of the engine/ transmission when under a hard load. What y'all think?

 

Check with eaton as kenworth and western star 2012 to2013 build trucks are having a recall for excessive clutch adjustment and shudder for all aust models , my customer just had one changed under warranty. Cause faulty springs in pressure plate causing uneven wear and throwout bearing issues

 

If you ever have a preasure plate out look inside the tube that the input shaft runs in, there is a brass sleeve, if it gets dry it will disintegrate, that allows the release bearing assembly to flop around. That will cause a vibration. You can not get the grease to ever get on the clutch discs, the sleeve end at the middle of the preasure plate and at worst it might get on the springs.
The clutch brake is also made to run in grease, if it is run dry it will wear out a lot quicker.
If you ever get worried about grease in the bell housing, when you are preasure washing it leave the engine running and there are extra holes in the bell housing for cross shafts put the muzzle in those holes and wash it out, or remove the plug in the bottom of the rear housing, put the spray in that hole centrifical forse will clean out the housing. and will not get in the release bearing.
Just a thought!

 

JohnP3 I have never heard of greasing the throwout bearing while the clutch is depressed. What is the reason for that? I know some guys grease it with the engine running.

 

I been chasing a vibration in my T660 . My steer tires last 9 months then there junk. I have bought 3 sets and had 8 3 axle alignments ,shocks,and many other parts replaced all for nothing.

I was so frustrated i was ready to give up on the truck and get a new 1. I gave it 1 more shot . I met Chad at MD ALIGNMENT in KC it cost me 350.00 . He basically jacked up the truck spun the wheels told me everything the truck was doing as far as how it drives he knows his business very well. So i told him to do his magic . He used a laser system that didnt look anywhere as accurate as a Hunter system. I told myself i just wasted 350. On this clown but sure enough 30 min later he runs the truck in out of the shop bay 5 6 times and gets a feel for the steering wheel . Jumps out of the truck checks the aligment again for 2 time give me a thumbs up im done .

I take the truck for a drive steaming this clown just got me . But that wasnt the case i noticed for the first time in 3 yrs my steering wheel is straight. And the truck drives better. So i get aload drive down the road all my vibrations are gone .


The symptoms alot of you are describing in here are a mirror image to what i had ,i swear most of the time you guys were driving my truck.

The problem is there are alot of mech out dont have a clue what there doing. They dont get that 3 axle true with a new set of steers you just wasted a 1000.00. The casing gets damaged truck tire will always have a wierd ware pattern. Took me 8 trys to get it right. But all my headaches are gone. I hope this helps . Give him a call . I hated spending that much money but im glad i did.