Thread: busted tranny

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I have been trying to find out why the tranny case cracked And a expert told me that if the engine was line bored it could raise the crank and cause the input shaft to be not centered to the crank has anyone ever seen this happen before he said there is a jig to correct the off center do you know where to get one?

Would have to be one heck of a line bore....................Probably cracked because it got stressed when the engine was put back onto it.

no. i have a customer that as a engine that has a .010+ up on the line bore and never broke any trans bells. this is on a drag car have had many out there that have a line bore with less crank drop.the bolt holds in the trans converter holds it to the fly wheel the crank hub bore and converter center up on the crank hub .so you would burn up the pump bearing if it was that far off to bust the bell.i would think .

There's far more then .010 slop on the converter to flex plate attachment. I line bore all my engine blocks and normally run a manual trans. I have a fixture to measure and make sure the tansmission mount is centered on the crankshaft centerline. Not sure how you could set one up with an automatic.... Are you sure the alingnment pins on the block are in good condition, and long enough to come all the way through the bellhousing holes???

i turned the trans. pans 350 and 400 (2 ea.) up against the floor board on a blown el camino 4 weeks in a row. sheared the bell-housing off at the pump. i was hooking to hard i guess (i changed everything on the truck) and with the blower, one of two things are gonna happen. you were gonna launch or break something. that when i built a blown drag only car and stopped dragging my st. car. has it happened more than once?

Originally Posted by Dave Severson

There's far more then .010 slop on the converter to flex plate attachment. I line bore all my engine blocks and normally run a manual trans. I have a fixture to measure and make sure the tansmission mount is centered on the crankshaft centerline. Not sure how you could set one up with an automatic.... Are you sure the alingnment pins on the block are in good condition, and long enough to come all the way through the bellhousing holes???

put the trans with out the converter put a dial indicator on the in put turn it around the crank hub or turn the crank with a dial indicator run it around the in put were this no splines just like when you would do a stick and if way off use the off set pins mr gasket sell would do the trick

Stick shift I would think has to be more ON the money as your pilot brgs in the crank. I would think the flex plate would compinsate for more than .010.

they do to a point the guys that use the super bell s.that cut off the old bells if you run them i was told that they can be out of line with the input .so i did not use one on my 400. i have never crack one in use but have welded them they are thin

Manual shifts are critical on input shaft alignment to the crank hub pilot bearing, I use the dial indicator much as Pat described. I've found so many block dowel pins out of alignment, it's not even funny!!!! Now they've come out with misalignment pins, used to have to do some creative machine work. Also, I've found that after I set my centerline, I torque (not just tigheten) the bellhousing to block bolts, then recheck the alignment. Occasionally torqueing the bolts can change the alignment!!!! Really crucial to get the alignment right on the soft-lok and multi-disc clutches.....

With all the up and down slop on a converter in the front pump, getting it within .010 probably beats the factory spec by .030!!!!!

ok great help THANKS!!