Hey Guys, Long Time No Hear.
I Got On Here A While Back To Tell Everyone That The 64 On The 76 Frame Was All But Done, Since Then I Have Pulled All But One Patch Of Hair Out!!!! Heres The Problem, If Anyone Can Help I Would Be More Than Greatfull!!
I Have A Model 24 Transfer Case And A Fe With C-6 Trans. That Has Short Shaft Between,i Have A Vibration More Like A Chatter When First Accel From Dead Start,seams Better At Speed But Still There.
Sounds Simple I Know- Here Is What I Have Done To Fix With No Changes In Symptom.
I Have Changed Transfer Case Heights,angles,ihave Made The Mounts Solid With No Change.i Have Changed Angles Between Trans And T-case Up,down,even With Eachother,side To Side And Even Made Trans Mount Solid And No Changes In Symptom.
I Have Changed Short Shaft Between T-case And Trans 3 Times And No Changes.
It Does This In 2 Wheel Drive Or With Rear Driveshaft Out And Running With Front Wheel Drive.it Does It On The Hoist With Brake Load On It,in Rear Or Front Drive With Rear Shaft Out.
The Truck Did Not Have This Prob. On Old Frame,ive Tried Everthing I Can Think Of,with No Changes. It Seems That With All Changes We Have Tried We Could At Least Make It A Little Better Or Worse, Nothing Has Changed At All.
So, If Anyone Has Any Ideas, Please Help, Sometimes We Get Caught Up In The Big Things And Forget The Simple Things,im Not To Proud To Learn Some New Lessons About Simple Things!!!!!
Thanks For Looking.
Gpa

 

I'm not that knowledgeable in tranny's or engines yet, but are you sure the chatter isn't coming from the motor?

Also, did you drain and replace the fluid in the Tcase?

 

my bro did somthing on the order of that it had the worst chatter in itwas runin a 205 behind a 4sp with a real short shaft betwween the them dont know why but we made new mounts and run a longer shaft between the two and it worked or make shure your shafts are "timed" rite

 

Slayer And 351
Running The T-case In Neutral, Theres No Vibration,but Theres Realy No Way To Put A Load On It, So I Dont Know If Its In The Trans Or T-case. The Fluid In The Trans Is Clean And Smells Good And We Serviced The T-case With New Oil So Both Seem To Be In Good Order. The Driveshafts Including The One In Between Trans And T-case Are Original Equipment Length. All Shafts Run Real True,thats What Has Me Puzzled. Hope The Info Helps.
Thanks For The Input, Please Keep It Coming.
Gpa

 

Have you thought about looking st the motor mounts?

 

Ok so with an automatic tranny, there's a chatter in forward gears and none in neutral. What about reverse?

 

The Motor Mounts Are New And I Have Checked Them For Any Play And Found None. The Truck Has The Vibration In All Gears Including Reverse. The Thing Is, Its Only On Acceleration And Under A Load. When You Go To Take Off It Shakes The T-case Shifter Like Its Going To Tear It Off!!!! 351- We Had The T-case In Neutral Not The Trans, So All We Runing Was The Driveshaft Between The Two,nothing Else,in Other Words, We Wanted To See If The Short Shaft Would Make It Vibrate Without Any Other Drivetrain Parts Moving, It Didnt Because We Couldnt Put A Load On It That Way.
Man, Ive Tried All The Things I Can Come Up With From Past Expeariances And Nothing Has Changed A Bit, Its Driving Me Crazy!!
Im Greatful For The Input!! Maybe This Info Will Help With Some Other Ideas, Please Dont Give Up.
Thanks,gpa

 

Did you check to see if the converter's pilot bushing proper size ???, under load it could , or may do this. Don

 

Yomow, When We Did This Swap The Engine And Trans Were Never Split And It Didnt Have The Problem Before,so I Think The Converter Ok.
What The Vibration Realy Feels Like Is Like When You Have A Bent Shaft Or A Carrier Bearing Completely Gone, It Is Pretty Violant Shake,thats Why I Thought It Would Be Easy To Find, But Ive Been Humbled Over And Over By This One!!!! Any Way, Thanks For Your Thoughts.
Gpa

 

flywheel? my 79 had a vibration and a knock sometimes (i thoght it was cam baering or crank bearing) kept driver father in law borrewed it was driving 60 and kaboom no more foward movment went to start it and screech the fly wheel had broke off in a star around the bolt holes har to see with out taking the fly wheel off (before it broke)

 

can you crawl up under it and snap a pic of the center shaft and post it??betting its outa time or somthing that cant be explained with words but if we could see it mabe somone could clear it up for ya.over the last couple months ive had to spend thousands to get all this rite on my work truck so there isnt much i havent seen as far as what could cause vibrations

 

Wizzard And 460429,
The Flex Plate Is In Top Shape,engine Runs Almost Perfectly Smooth And With No Noises.
As Far As Yoke Placement They Are Phased Perfectly, The Shaft That Was In It First Was The Oe Shaft And We Have Put 2 Others In Since. They Been Balanced And Dead Straight.
Ive Worked On Drivetrain Problems For Years And Havent Had Any Like This One, All Things Mentioned So Far Are The First Things We All Look For, But This One Has Really Whipped Myself And My Co-worker!!!!!
Any Help Would Be Great.
Gpa

 

You sound like you were pretty through. Is there anyway you got a bad u-joint that is rattling and causing your vibraton? I would say check to make sure your wheels are balanced but it wouldnt happen at low speeds if it was a whell that was inbalanced. Check your u-joints. Thats all I can say, this is very strange.

ON EDIT: What about the tires? Maybe there worn funny and causing this vibration?

 

352. We Changed All The U-joints,wich Doesnt Mean Their All Good, But The Driveshafts Run True With No Noises And No Deflection. The Reason We Dont Think Its Tires Is It Will Do The Vib. On The Hoist In Two Wheel Drive Four Wheel Drive Or Front Wheel Drive With Rear Shaft Out.the Shutter Is From A Dead Stop Too About Maybe Ten Too Fifteen Mph And Then It Seems Like Its Got A Harmonic Vibration But Not Real Bad. Guys, This Is Why Its Driving Us Crazy, We Have Covered All The Basics And Then Some!!!
Thanks For The Input, Please Keep Trying. We Have A T-case Comeing Monday That Were Going To Try, Lets Hope For The Best ,but Any Other Ideas Would Be Great!!
Thanks. Gpa

 

With all you've changed and done and with all of your extensive experience with past drive line troubleshooting it sounds like you've exhausted the obvious. You mentioned the engine and tranny were never split. How long was the motor/trans sitting? When you think of something that has enough mass to cause that kind of vibration and only when in gear and excluding all of the items you already tried I would suspect something with the torque converter and flexplate. You said it runs smooth and with no noises. Are you looking at it on the lift before and after it is in gear? Watch for vibration as far forward as possible and eliminate the engine if possible. I actually had a broken crank that snapped forward of the forward-most rod journal but it broke such that it still messhed perfectly and only vibrated under load. The whole truck shook fiercely but I could still drive that Ford home!