Bolts missing --> Cracked 904 case

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CordobaDart

CordobaDart

318 SLANTMAN
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Location
Wabasso, Minnesota
So I am finally getting back to work on my 73 Dart Sport. 318/904/8 3/4"


Here is a quick run down on what is going on here.

When I first got the car, it had a bad driveline vibration that the previous owner thought was u-joint/drive shaft related.

I first checked underneath to find both U-joints were tight, one even looked new, then I spotted that the rubber in the trans mount was shredded. I did not see anything else amiss at this point.

So I picked up a polyurethane trans mount and put that sucker in. The car felt noticeably better already but there was still a driveline vibration.

I took the drive shaft to a reputable shop in my area and had it balanced at the cost of 40 bucks. This did not help the car at all and the vibration continued. I only took the car out for a couple short blasts around town every other weekend or so, as highway driving was far from smooth and something else was obviously wrong with the car.

While under the car draining the engine oil, I noticed transmission fluid dripping from the pan and figured it needed a new pan gasket. A couple moments later I spotted something odd about the flexplate, as it looked to be aftermarket, I took a closer look. Only to find that the flexplate was badly cracked in multiple places. Hmmmm.

As I proceeded to eye up the situation, I noticed something that gave me the "Aha!" moment I had been looking for. There were a couple bolts missing from the transmission bell-housing to engine and there was a 1/4" gap between the two on the passenger side! I finished the oil change and took a look from up top. There were more bolts missing up here as well! Turned out that only three bolts were holding the engine and trans together, the two starter bolts, and one above those two.#-o

I gathered some bolts and bolted everything up, backed it out of the garage, and parked it in the car port for when I could get to dropping the transmission.

I finally got time to remove the transmission from the car and replace the destroyed flexplate. The car fired right up, I backed it into the street, did a quick little burnout to lift my spirits, and drove the car into the garage.

Got the trans dropped and voila! A huge crack in the case along the casting line where the pump mounts... It was now time to tear the trans apart.

I had a 904 in the corner with a smoked kickdown band to use for parts and the case so that worked out well for me. I have not rebuilt a torqueflite yet but my friend who has some experience with them helped my inspect all the internals. The best parts from the two are now all laid out ready to go, I will be ordering my seals/clutches/steels next week.

I do have a small block 727 in the shed I could just built instead but the torque converter that was in the car is a TCI 142300 which is not a cheap converter, and the car did work well with it. So I am sticking with the 904 setup. My new b&m flex-plate came in the mail and it is ready to install.

I am kind of paranoid that bolts are just going to start falling out now, and plan on using locktite on the converter bolts, but should I use locktite on the flexplate to crank bolts? Should I use locktite on the engine to trans bolts, lockwashers on the bolts, or both?

Thanks for reading about my silly problem. Here are some more pictures..

I put a flashlight inside the case on one of the below pics to better show the crack in my piece of scrap aluminum.
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Thanks for reading/looking.
 

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My guess is that someone didn't get the converter seated all the way into the front pump and pulled it in with the bolts. Possibly leaving a gap between bell housing and block. Once the crack progressed it relieved the load on the bolts and they vibrated out. I personally would use a torque wrench and torque things to spec. Maybe use some on the flex plate to crank and converter bolts.
 
That does sound like a possible explanation on how this happened.

I am definitely leaning toward using locktite on the bolts going into the crank and converter.

I can torque the converter bolts and flexplate to crank bolts no problem, I will have to find the torque specs on those.

As far as the bellhousing bolts to the engine, there is no way I will be able to fit a torque wrench on those, so some new lock washers and bolts will have to do.

Also there were more than a couple other things going on with the car that suggested some inexperienced work had been done to it. I have learned lots from repairing this car so far.

Thanks for the reply Dubob
 
i think the mechanic didnt tighten the bellhousing bolts and they fell out.or just didnt seat the trans tothe block.i have fixed this issue twice on cars myfreinds bought. just make sure everything is tight going back together you will be fine....
 
At least it appears you found the vibration.
 
I also bet the last guy didn't tighten the bolts good. Who knows what he may not even installed all of them. I saw that once when I was young. The kid down the street from me bolted a Buick trans to his Chevy engine and the only bolts that lined up were the bottom 2 so that's all he put in. Broke the trans case in no time at all.

I use blue Loctite (medium strength) on the flexplate to crank bolts and flexplate to torque converter bolts but have never used it on the trans case to engine bolts and never once had a trans come loose.
 
i was being nice,lol might not have put them in at all....lol
 
Follow up on this post. I just finished the rebuild, it went well and I have celebrated already with some short burnouts(though burnouts are not as smokey or cool at 10 degrees F, dang November cold) and am happy to say disaster and problem averted.

My first torqueflite build welt well with the help from a friend and specs(excluding tolerances, those all checked out within spec) are as follows:

TCI converter 142300
Alto Red clutches
Raybestos Pro Series kickdown(direct drum) band
Re-used a factory double-wrap low reverse band
blocked the accumulator down against the valve body
TCI 4.2 band apply lever
Re-used the valve body that was already in the car(it worked well with it, but I have no idea what shift kit may be in it)
And all new seals of course

The old trans case has probably been smelted into a KIA by now.

Most importantly, I put bolts in all the holes and properly TIGHTENED THEM. I will have to follow up again after I get the chance to take the car out again.

Happy Thanksgiving all.
 
Looks like you got it figured out..and You Cracked the case...
 
When I had the transmission out I noticed my Dart Sport has what looks to be a .45 caliber bullet hole that was hastily covered with a piece of steel and self tapping screws. Whatever trans was there when that happened would have been toast, likely proving torqueflites not truly "bullet proof". The factory column, carpet, seats and driveline are long gone too. Makes me curious of where the car came from.
View attachment IMG01193-20131122-2107.jpg

View attachment IMG01192-20131122-2106.jpg

View attachment IMG01191-20131122-2105.jpg
 
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