Thread: c6 fitting problems

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Trying to get the c6 tranny bolted to the 460 today. Had it together but the torque converted was jambing, took it apart and realine the torque converter, which sort of press fits into the flexplate/flywheel? Once they were connected we slid the tranny up the torque converter shaft, but the housing wont come together. Guessing some of the splines aren't lined up. Any tricks wopuld be appreciated. Steve.

Stovens; There are only a couple things I can think of that would cause that problem.
One is the alinement like you said and you should have a cheap alinement tool for that!
The other is what was behind the 460 before, if it was a stick shift look in the back of the crank and make sure there is not a race in there.
This would keep it from slidding all the way in. Hope this helps Kurt

Steve: I'm a little confused by how you described putting it together.......you weren't bolting the convertor to the flexplate THEN mounting the transmission to the convertor, were you? What you need to do is first put the input shaft into the transmission till it seats. Then put the convertor onto the input shaft and slightly elevate the front of the transmission so gravity is helping you. Turn the convertor round and round and it will start seating itself into the transmission. It will seat deeper until it finally seats all the way down in. The input shaft consists of a shaft within a shaft, so you have to get all those splines aligned for it to drop in all the way.

Sometimes you THINK it is seated all the way down, but it still is sitting one step up. That final seating will be noticeable as it drops down to the correct depth. As a check, you can measure from the engine block surface where the tranny goes to the level on the flexplate where the convertor bolts on. Then compare that dimension to what you get from the front edge of the transmission back to where the convertor is resting.

Finally, make sure your flexplate is not mounted backwards. You wouldn't be the first to do that. Some are marked out or engine side, but not all are.

My bet is that your convertor isn't fully seated down in the transmission though.

Don

Did an engine swap 302/C4 into '83 Mitsubishi pickup. Motor/trans had to go in as a unit. Got it in, mufflers and pipes all connected and mounted, fuel lines connected, cooling system ready to go. Just ready to fire it off when I turned around and spied the converter/pump driveshaft sitting on the toolbox.

Originally Posted by techinspector1

Did an engine swap 302/C4 into '83 Mitsubishi pickup. Motor/trans had to go in as a unit. Got it in, mufflers and pipes all connected and mounted, fuel lines connected, cooling system ready to go. Just ready to fire it off when I turned around and spied the converter/pump driveshaft sitting on the toolbox.

Fewer parts just make them more efficient Richard.

Don

Originally Posted by Itoldyouso

Steve: I'm a little confused by how you described putting it together.......you weren't bolting the convertor to the flexplate THEN mounting the transmission to the convertor, were you? What you need to do is first put the input shaft into the transmission till it seats. Then put the convertor onto the input shaft and slightly elevate the front of the transmission so gravity is helping you. Turn the convertor round and round and it will start seating itself into the transmission. It will seat deeper until it finally seats all the way down in. The input shaft consists of a shaft within a shaft, so you have to get all those splines aligned for it to drop in all the way.

Sometimes you THINK it is seated all the way down, but it still is sitting one step up. That final seating will be noticeable as it drops down to the correct depth. As a check, you can measure from the engine block surface where the tranny goes to the level on the flexplate where the convertor bolts on. Then compare that dimension to what you get from the front edge of the transmission back to where the convertor is resting.

Finally, make sure your flexplate is not mounted backwards. You wouldn't be the first to do that. Some are marked out or engine side, but not all are.

My bet is that your convertor isn't fully seated down in the transmission though.

Don

Don thats exactly what I did!
Kurt you were right it wasn't seated all the way back. it required alot of finese to get it all aligned. So a couple of hours later we had it all apart and back together again. I noticed when I sinced down the housing bolts and coverter I couldn't turn the engine over by hand, but it is seated all the way, and did go together easily the third time!
We next try to fit the engine in the bay, but one side mount got held up against a shock absorber mount bolt on one side. I can cut back the base of the mount to get the clearance, but I think I'll try cutting the old tranny crossmember back a bit to allow the c6 tranny to go further back into the firewall, which should also solve the problem. Clearances are very tight in front, so the farther back it goes the better! Right now the way it wants to sit, the crank pulley will hit the front crossmember. I know it will work, because the motor mounts are made for this specific application for this year truck as are the headers, so just more cutting and tweaking. Patience grasshopper!

Of course, I personally have never made a mistake like that. I also have this great bridge for sale that once resided in London.

Don

Actually I wanted to thank you all for at least getting me over that hurdle. Anyone know the torque specs for the torque conveter nuts?

If I remember correctly Steve, they should be 7/16 size and go to 55 ft lbs, I like to torque in increments. Go 20 all around, then 40, then end up at 55 all around. BTW, did you prefill the torque converter with fluid? You will want to turn the snout up and put enough fluid in there so that you can look down inside and see it at the bottom of the snout.

Don

Don it was prefilled by the guys who rebuilt the tranny. A little fluid came out we we were taking it off the tranny and reseating it, so it should be ok. It is just wierd that I could turn the engine over while sequencially tighting the bolts on the converter, but when I sinched the bolts tight and tighted the bell housing to 25lbs, it would no longer turn over. I'm fairly sure the torque converter was seated all the way down. So I'm a bit mystified as to why I can't hand crank it over now. My only thought is that something is binding against something else in there right now, not allowing it to turn properly. For engine mounting purposes it is ok for now to leave it alone until I get the thranny bracket and motor mounts aligned, but it sure would be nice to fix it now, before mounting everthing, one less thing to do!

Well at least I now know that I was not the only kid watching Kungfu. Kurt

Well I have an idea as to what the binding issue may be. I was told there are two different torque converters for early model c6 transmissions, and that the diameters of the shaft on the converter where it slides into the back of the crankshaft are different. So when we originally mounted the converter first to the flywheel, it would not slide into this slot. The bolts barely went into the flexplate holes, to where we could only get a few threads on at a time and slowly had to work them around to get the torque converter on. It did eventually go on but could this be the problem of why it binds up when the housing is torqued on? Just trying to figure this out now, before I go to work so I know where to start tomorrow! Any thoughts ford people?
should the torque converter fit less tightly to the back of the crankshaft or should it have to be bolted into place to press fit the shaft into the back of the crankshaft seat?

Its snug but not a press fit buy far.
Did you know what was behind the engine before?
And did you make sure that there is not a race in the
back of the crank. That will keep it from seating too.
This will also make it hard the get the converter nuts on.
Kurt

Thanks Kurt. The old motor is gone, and the transmission place rebuilt the old transmission last summer, and gave me a new torque converter that supposedly was the right one, though the old one was recycled by them when I picked up the new one. Not sure about the race in the back of the crank. I'm sure I'll have to pull it apart tomorrow, so I'll call the tranny shop and post pictures of whats there on both sides. It may be that the new longblock has a different style to the rear hub on the crank shaft?

Well I took the torque converter out and back to the transmission shop. Sam the main guy there remembered me, said he'd run the numbers of the torque converter and see if they could locate one that fits the pilot to the crank. Very nice guy, no questions or hassles even though they rebuilt it last May! He said he should be able to get the right one by tomorrow or the next day.
I'm working till the weekend so it really doesn't matter, I managed to pick up some bug at work that seems like a cold or sinus infection, so I guess this week just wasn't meant to be!