Help with 4 speed trans install

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Veryfastdart

Veryfastdart

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I have a 69 GTS 340 4 speed. We call it the "Bastard Child", It was purchased as a disassembled basket case. The issue is I installed the bellhousing and it fit flush on the block. I installed the transmission and it wouldn't go all the way in the bellhousing. It was out about an 1/8". The crankshaft has a new needle bearing in it. The clutch was installed and aligned. The transmission was in neutral and the tailshaft turned freely, until I tightened up the 4 bolts to pull the trans into the bellhousing. I then heard the "POP", I just cracked the aluminum bellhousing. "DAMN"! I pulled the trans out and the bellhousing off, located the crack, TIG welded it and tried to re install it. Same problem, 1/8" gap and it stops?? The tail shaft turns freely, UNTIL I tighten it again, now the shaft will not turn?? Also the bottom of the bellhousing pushes out the 1/8" that the transmission would not go in.
I assume the input shaft is hitting the end of the crankshaft?? I'm going to remove it AGAIN and cut the tailshaft down. I will measure from the inside deepest point of the crankshaft to the outside of the bellhousing. My question is, IF this is the issue, How much should I cut off? My gut feeling the 1/8" that it won't go in now plus a 1/4"?? So 3/8"??? thanks
 
I believe 1/8" clearance is plenty..
FWIW, Here's some numbers I came up with for a 440 with a steel auto trans crank and un-cut trans input...…...
InputCrankDepthDiam.jpg
 
It sounds like a bunch of unknown Parts going together wrong. Possibly, I know this sounds labor-intensive, but trying it with a different or a testing bell housing. Maybe someone else will step in, but I've never heard of anybody having to cut the end of their perfectly good transmission off in a stock application.
 
I'm not sure the crank shaft was drilled for a 4 speed? But the Needle Bearing went in, so maybe it was? Maybe just not deep enough? I have heard of plenty of people cutting the input shaft, I agree, I shouldn't have to, but I don't know what else to do?
 
Yes, but only using the aftermarket pilot that fits in the converter register on the crank. If the crank doesn't have a pilot bearing hole in it but has a retrofit roller bearing but in the converter register then the pilot should be trimmed back to give about a little air gap between the end of the crank and the pilot. You only need enough pilot to go all the way through the bearing.
 
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^^^ See skep419 post. Did you test fit?
Per MP, all the stock bells are 7.380". Then too, a block saver from a previous scatter shield setup might be the gap you are missing.
You'll need to measure your set up to know exactly what you have. Measure twice, cut once.
 
So that would mean the pilot bushing hole would have to be at least 1.245 in the end of the crank, right, might be a pain, but could you mock up all the components out of the car (except the motor of course) add the numbers and then measure the depth of the pilot hole, and add that also, them measure the assembled mock up. and make sure the needle bearing is fitting on the trans input shaft right. Just some thoughts, been outta the game a while.
 
Thanks for all the comments, I'll measure twice, cut once! I'll let all of you know how I made out next week!
 
Yep, I have forgotten the procedure, but Ya use a dial indicator to precisely align the trans and the pilot hole, if it's offset, ya use offset dowels to center the bells trans hole and the pilot hole.
 
" I'm going to remove it AGAIN and cut the tailshaft down."


Why are you wanting to cut the the tailshaft when it's the input shaft having the issue ?
 
With a crank not drilled, about 5/8" off the input shaft will work.
 
I had a hydro lock issue similar to this. I put grease on the input bushing when I put it in, and I must not have cleaned out the hole. I couldn’t get the trans to go all the way in no matter what. Hammers, tightening the bell bolts one at a time, nothing. I cleaned the pilot hole and she slid in like butter off a hot biscuit
 
AJ/FormS said:
I've never used a needle bearing pilot, and I don't think I ever would. I think it would eventually wreck your input shaft. IDK, but there's at least two better ideas, IMO.
Click to expand...


Seen them used many times with no issues, If you ever need to replace the input shaft there around $90, just bought on the other day online.
 
Cut the shaft and all is well now, took 3/8" off and beveled the edge. Looked inside and saw where it was contacting the crank!
 
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