Vintage Mustang Forums banner

1 - 13 of 13 Posts

·
Registered
Joined
·
656 Posts
Discussion Starter #1
I built a new engine for my coupe and this weekend I put it in the car. Now that I'm hooking up the transmission I'm having a problem that I know can't be good.

I've got a C4 Auto, the same transmission that was already in the car. I'm also using the same flexplate that was in the car. I am using a different torque converter, though, but it's one that I've pulled out of my convertible's C4.

My problem is that when I bolt up the transmission to the engine and tighten the nuts that attach the torque converter to the flexplate, when I spin the engine around to the last nut on the torque converter the flexplate hangs up on the starter gear. When I watch it I can see that the flexplate has plenty of clearance from the starter gear all the way around until right before it gets around that 4th nut, then it seems as though it just pulls in and catches the starter gear teeth.

I've tried two different flexplates, two different starters -- and all with the same results. After I bolted on the latest flexplate I bolted onto the engine a plain old C4 bellhousing and a starter and spun the engine around with absolutely no clearance issues whatsoever, but once the tq converter gets added into the equation I have problems. I'm pretty sure that it's all the way in place on the transmission...

What should I be doing different or checking out?

I'm really going crazy over this...

Thanks!!!
 

·
Registered
Joined
·
767 Posts
I'm having a hard time picturing exactly what's going on from your description, but are you absolutely, positively, without-a-doubt certain that your torque converter is fully seated down onto the input shaft of the trans?

It's pretty easy to put it on and think that it's correctly seated, when in fact you need to spin it around a few times with light pressure towards the trans and everything will suddenly line up and it drop in another 3/8". Very common.
 

·
Registered
Joined
·
656 Posts
Discussion Starter #3
I WAS pretty sure that the converter was all the way in, but I think I should probably quadruple-check that again. I guess that if I'm not having problems when there is no converter in there, but lot's of problems when it is there then it must be my problem...

But I know that I was spinning the converter to try to get it to seat all the way down, but it didn't seem to want to go any further in. Should there still be some wiggle in the converter when it's correctly seated?
 

·
Registered
Joined
·
656 Posts
Discussion Starter #4
Just to add a little bit more...

The transmission and the engine slid right together without any force and I was able to put all the bolts in that attach the two without any problems. I figured that since it just went right together that the converter must have been all the way in...
 

·
Registered
Joined
·
767 Posts
There is some fore and aft play, and when you bolt it to the flex plate, it gets pulled out a bit too, so it's definitely not an interference fit or anything. There shouldn't be a lot of side-to-side "rocking" type play.

If you have the trans out (or like me, are willing to take it out once you spend 2 hours getting frustrated enough to spend 15 minutes pulling it), I'd go to the bench and seat the new and old torque converters on the shaft a few times to check a couple things:

1. That they are the same.

2. That you get a good feel for that "extra" engagement when the front pump is engaged.

When you feel it engage that last tang, you'll know it's right. (And hopefully it'll be different than before, so that you'll know it'll go back together and work. ;) )
 

·
Registered
Joined
·
767 Posts
DannyOO said:
The transmission and the engine slid right together without any force and I was able to put all the bolts in that attach the two without any problems. I figured that since it just went right together that the converter must have been all the way in...
That usually does mean that. I think I'd still go hit the bench with the parts and mix/match/try until you are totally sure that the converters seat the same.
 

·
Registered
Joined
·
4,209 Posts
Ok let me try to help since I have a c4.


First the Torque converter needs to be seated properly. Make sure that you have pressed it while turning back and forth till it clunks 3 or 4 times.

Have the starter off and to the side.
Then When putting the Trans to the block the two alignment pins and spline should all go together smoothly. You will know if all is together correctly because through the WHOLE precess you should be able to grab a torque converter stud and freely rattle its rotation in the flex plate wholes. I finger tighten all of the mounting bolts and then last check to make sure the Torque converter is loos as a goose to the flex plate.

do not use a wrench until you know ... may I repeat...the torque converter is free and loose to the flex plate.Then when all studs are securing the trans housing you can put the nuts on the Torque converter finger tight while rattling each one to make sure the stud is centered. This process is the longest one because you have to advance the flex plate tooth by tooth to do this properly. at least four revolutions so you do not torque the nuts un evenly.
 

·
Registered
Joined
·
656 Posts
Discussion Starter #9
Ok, thanks guys!

I'll get back out there now and pull it all apart and see how it goes...
 

·
I won a special award
Joined
·
7,409 Posts
The very first time I put a transmission in the car in my signature, I had the exact same problem as you. What I did was not have the converter seated all the way in the transmission. When it's not seated correctly it will bend the flexplate forward towards the engine causing the converter studs to hit. And yes, the engine and transmission went together easily when I did that. There are 2 sets of splines you must get the converter seated on. You need to lightly shake the converter up and down and slowly rotate it while seating it. You should be able to feel is seating on splines.
 

·
Registered
Joined
·
656 Posts
Discussion Starter #11
Well thanks guys!

It appears that somehow or another the converter just wasn't quite in there right because now I'm good to go.

Now I hope that everything else goes well so I can get my newly built engine fired up for the first time today...
 

·
I won a special award
Joined
·
7,409 Posts
You gotta love this forum for stuff like this. I wish it had been around 25 years ago when I had my other car. I probably could have avoided a lot of the screwups and other mistakes I did.
 

·
Registered
Joined
·
656 Posts
Discussion Starter #13
I figured it all out. My converter was actually all the way in all the time. My problem, and I'm posting this so others don't overlook this as well, is that when I lined up my converter to my flexplate I only lined up ONE of my converter drain plugs with a hole on my flexplate. I can see the mark on my flexplate that the second drain plug made when I tightened it down.
 
1 - 13 of 13 Posts
Top