Been lurking – and have found good info here.
So, I am a new member & this is my 1st post.
(yes, I have been searching the archives)

I am the relatively new owner of a 1992 F250 –
5.8 / AOD / D-50 TTB / BW 1356
I bought the truck @ 1 year ago knowing that it had front axle &/or 4-WD issues,
and have driven the truck over 5k – exclusively in 2-WD w/ free hubs.
In this mode, I regularly heard a noticeable single "clunk" noise
when shifting into drive or from drive to reverse and when coming to a stop.
I didn't think too much of it.

Then the truck experienced a major calamity:
A vibration appeared while driving (2-WD w/ free) that quickly (@ 50 miles)
grew louder and worsened until the TC was shaking about violently.
I observed that the TC tail-shaft bushing and seal had spit out of the casting,
and that (still in 2-WD / free hubs mode) the front drive-shaft would not turn.
I limped the truck home, and began the search & repair.

I removed the front drive shaft to find that the D-50 pinion bearing was shrapnel.
I thought this was odd since the bearing had obviously deteriorated
since I had inspected it at the time of purchase –
and the truck was only used in 2-WD w/ free hubs (?)
The TC front output yoke seemed tight in it's bearing and spun freely.

I refitted the tail-shaft bushing,
installed a new seal and a new slip-yoke (old one was measured to be worn past limits)
At that time, it seemed to me that the TC output shaft
had excessive end-play (no spec to verify) but little or no axial play (?)
Both rear drive shaft U-joints (also junk) – replaced
Driving the truck with these repairs but w/o the front drive shaft fitted
lessened the clunking noises and virtually eliminated vibration.

On to the front axle.
Everything inspected at tear down.
All 3 axle U-joints – replaced,
2 front drive shaft U-joints – replaced,
driver side spindle bearing – replaced
Associated seals – replaced,
4 worn ball joints – replaced,
and a used but solid JY D-50 replaced the trashed unit.
Grease and oil for everybody.
The front drive shaft was reinstalled.

Without that symphony of noise caused by worn axle and diff parts –
I am still (in 2-WD w/ free hubs) hearing a banging noise, sometimes repetitive, while coming to a stop,
especially on downhill slopes (it seems).
Now sometimes accompanied by grinding noises, too.
The noise now sounds to me as if the TC is trying to engage 4-hi on it's own
by banging the parts into submission.

The BW 1356 vent hose is clear, and the external shift linkage appears to be in working order,
although it takes some effort to shift the TC into any position and especially neutral and 4-low.
I will be headed out after posting this to take another look at the external linkage and to check the trans mount.

In the meantime ...

Is there anything that might have happened inside the TC
to cause these symptoms ?

My suspicions are:
the internal shift linkage,
the rear shift fork or it's facings,
or something with the lockup assembly ...

Any leads, thoughts, or ideas to put me onto the short road to a solution ?
TIA

 

The shift linkages seizing up are a common issue on these trucks, I suppose it's possible it's not letting you put it fully back into 2WD. Only fix is to take the linkages all apart, clean the corrosion and grease all the joints.

The 1356 has a known issue where the oil pump will fail, and starve the case of oil. This could be why the rear output bearing/bushing blew out.

Also, are you sure you have an AOD? What's your transmission code on the door sticker?

 

I'll be taking your advice re: linkage for sure.
FWIW - trans operates flawlessly. Code = G

 

I swapped the BW1356 on my dad's 95 F350 with one I got from craigslist. The "new" one came with the link between the TC shift arm and lever. They were different lengths, and neither would work. I had to modify one of them to get the right length.

 

Lead Head – You may have been on to it –
Without taking the linkage apart,
but rather using my time, a liberal application of Kroil,
followed by a vigorous wire brushing and some grease ...
the shifter is now moving cleanly and smartly into all of it's positions.
Preliminary testing in the drive still has a "clunk" when shifting to drive ...
but none of the banging and grinding I had heard earlier.
Tomorrow's further test-driving will tell if the problem remains,
but, even in the worst case scenario here,
your advice has eliminated a bad situation.

Thanx !

 

Apparently not the external linkage.

I am still often hearing and feeling the same double clunk and grinding
happening while coming to a stop.
The clunk sounds and feels as if it is the front axle trying to engage.
I can "feel" the grinding with my hand on the TC shift lever ...

Once stopped, the front drive shaft is free to spin, as it should be (2-WD).