Engine to transmission issue

[maxwellwedge]

Hi All. Not Charger - but a T/A Challenger with 727.
This has perplexed me for awhile now and I have an opinion on the problem I am experiencing.
I keep eating transmissions. I substituted the matching 727 for a known, good working one. Same issues.
The trans works fine for a short while then leaks massively - mostly from the input seal.
I tried different flex plates and convertors. Even, as I said, a good working trans from another car.
I have never had the engine apart - but I suspect the crank journals possibly were align bored/honed incorrectly - making the engine to trans alignment cock-eyed? Is that something that could be causing the transmissions to fail? Side load?
I don't know if the offset bushings used on a 4 speed bell housing would correct this - and even if it's possible to do with an automatic. But if the crank centerline is tilted off center, it probably won't help.
Can the mains be welded up and corrected to where they are supposed to be? The drive train is original and matching and I want to keep it that way....and be able to drive the car without issues. I think I need to find someone that can tackle the engine with trans line-up in mind.
Any thoughts from peeps like Challenger340, John K? 

[John_Kunkel]

It's quite possible for severe misalignment to cause front seal failure, this is usually accompanied by one-sided wear patterns on the bushing and an abnormal wear pattern on the converter hub.

Are both dowel pins in the block extended far enough from the block to ensure full-depth engagement with the trans? Sometimes the dowels get pushed in too far and won't properly align the engine/trans.

The empty transmission case can be dial-indicated and offset bushings used to correct any misalignment.

[maxwellwedge]

Thanks John.
I believe the dowel pins were ok. I'll pull the engine and trans and recheck.
I wasn't sure if you could align an auto trans case like you would a bell housing - that's good news.
I still don't trust the engine build. The engine seemed to run ok, but I want to check that as well.
Challenger340 - I'm in Ontario - do you want to do that engine for me? We can see what a stock headed, small block 6 pack will do 

[c00nhunterjoe]

I would think if it is burning out bushings and seals that fast, it should be easy enough to tell when trying to bolt the converter to the flex plate? If the holes dont line up without persuasion, its obviosuly a problem. If they all 2 finger in, i doubt alignment of the crank iw off, but like john said, only wqy to verify is measure

[maxwellwedge]

After fixing the original trans a few times, and then trying another, all within a month - I got pissed off and parked it a few years ago. I don't totally remember if the bolts were two finger - but I seem to remember they didn't go in "like butter".
I'm going to redo the engine anyway and make sure everything is as it should be, crankshaft-wise. I'll have the trans to engine alignment checked then as well.

[Jake0625]

Did you have the engine rebuilt at any point in time? I had a truck that would kill input seals and wipe out the tranny turned out to be lateral movement in the crank the thrust washers were toast. It allowed the crank to slide front to back almost a half inch. If the alignment is all good it's something to check.

[Jake0625]

To add to it I couldn't even tell the crank had that much movement by the way the engine ran granted it was a 318 but still truck never missed a beat which is surprising with how much movement I had.

[62dodge]

Just a quick few questions was the engine properly balanced, is the torq converter correct for the engine, is the balancer correct for the motor

[maxwellwedge]

I believe everything was balanced - engine-wise. It's been over 10-12 years so my memory is foggy. But I used a good shop for this and other engines. Makes me wonder though....as the same thing happened to a replacement trans I tried.
I will get the engine apart and check crank alignment, balance - etc. As well as checking the trans to block alignment.