what should I do???

[Double-S-Diesel]

found .100 end play in the crank on the old motor with 284k, last sunday
swapped it out for a motor with 252k
pulled the oil pan off the old motor to see which side of the thrust bearing was shot, back side was bad along with the crank, there was no wear on the front side at all, there was some wear on the main part of the bearing, but not bad.

from what I know all that would wipe out a thrust bearing is if the TC was pushing on the crank.

dropped the inspection cover and loosened the Tc bolts, the tc slides back about 1/16 so I know its not pushing on the crank

truck had a trans put in 30k ago

Im wondering if the damage was done before, or from the old trans?

should I pull the trans and look further.
should I run her till she dies again

 

[trackspeeder]

Run it till it croaks.

I would think the damage was already done by the previous tranny. There is plenty of play in the converter. So that shouldn't be a problem. Did you recycle the flex plate from the old block? If you did, check the center for cracks. Bad thrust bearing will take out the flex plate after awhile.

 

[Double-S-Diesel]

checked carefully for cracks, seen my share of them.
I have only put 10k on the truck since I got it, would not have found the end play had it not been for the bad oil pump orings I was gonna change

 

[OLDBULL8]

[QUOTEfound .100 end play in the crank on the old motor with 284k, last sunday
swapped it out for a motor with 252k
pulled the oil pan off the old motor to see which side of the thrust bearing was shot, back side was bad along with the crank, there was no wear on the front side at all, there was some wear on the main part of the bearing, but not bad.
][/QUOTE]
What would cause the back side to wear like that other than a bent rod? If the TC was pushing wouldn't the front side of the thrust bearing be worn? The splines on the TC and tranny pump would allow movement without effecting the engine crank.
Standard crank end play should be .004 to .008 and service limit is .012.
Personally I would just put a new thrust bearing in and see what happens, who knows what the history was. With a new bearing in, rolling the engine over with the pan off might tell you something.

 

[Double-S-Diesel]

crank is too wore to just put a new set of bearings in.

 

[sle2115]

If I have this straight, you are asking about the running the motor that is in it? (replaced after end play was found) correct?

If that's the case, I'd say run it till it dies! Personally, I think you hit the nail on the head, the old tranny probably was the issue and with torque converter clearance like you've checked, I'd think you are good to go!

If you were going to use the motor you took out, then I'd say give it a thourough going over, check the rods, etc. but I still think you found the problem.