This ZF S5-47 is originally from a 460 superduty.
It looks like there may have been some play in the pilot bearing.
The current bushing is one of south bend's kevlar bushings.
I'm leaning towards the TIMKEN FC65662.
I received a call from the shop and they are finding nothing wrong
Being 4th is a direct drive any play in the system is multiplied there.
I tried to not say anything but I just can't stop myself from offering my tinhorn armchair quarterback opinion on the things that scream at me on this one.....
First...I have never been a fan of using a 460 case behind a 6.9-7.3 diesel...
Yes, I am sure there are some who have done it and it worked
fine for a million miles...
but...the locating dowels are different and the bolt holes that
may line up have too much clearance (in my opinion) to get the crankshaft and the input shaft centerlines located to the point that you will not have trouble down the road...
the whole thing just seems to be a wishful-thinking crapshoot...that I would not stake my reputation on....the only way to pull off something like that successfully would be if a good machine shop had built a template that would give you the places to drill or bush holes in the exact right locations to get it all lined up within an acceptable tolerance.
Speaking of tolerances...I am curious of how much clearance/preload the mainshaft on this unit was set at...if the input shaft has
any wiggle...anything other than being able to turn with some torque drag...the endplay/preload is too loose and will cause the popping out problem.
These are tapered bearings and the whole thing was probably designed by some german that would rather take a beating than to draw up a transmission that had loose tolerances...if you have had
any experience with any german-manufactured products you will notice how much pride they take in their reputation.
On pilot bearings...I always opted for a needle-bearing version...but...I also made sure that the tip on the input shaft was case-hardened and in good shape...and...I always used moly lube on the needles...I never trusted the lube that was on it to begin with...in case some pencil-necked bean counter decided to monkey with the lube spec before it went out the door.
Back to tolerances....I have run across a number of folks that work on stuff and assume that "what it came in with" is good enough for them...
I disagree...if I build the unit...I am measuring everything in sight and making sure my clearances are spot-on...this includes having to have bearing shims on hand to adjust the preload on the mainshaft and countershaft.
Without being too obvious...I would casually ask the rebuilder what specs he uses on this kind of unit and then watch and listen closely to the answer.
One thing that comes to mind other than the good suggestions the other guys have offered is fork wear...or anything that would keep the slider from going completely into its spot to couple up...and you ought to ask to examine the unit yourself and look for any wear on the fork, slider, hub, and engagement teeth on the input shaft...get a magnifying glass if you have to and give those parts a real going-over. ...oh...and the shift rails...look for wear at the shifter end as well.
Without being able to see the unit disassembled this is all I can offer up...
The popping-out problem is caused by the coupling parts not being paired up adequately, excessive wear on said parts, or the input shaft is wiggling and/or skewed...that is...not rotating on the correct centerline from mis-alignment.
Wishing you all the luck you can muster on this one...
Just my .02.
Merry Christmas to all of you, by the way...
