304 will not rotate.

Gearhead

Gearhead

Member
I recently pulled the 304 out of my 1969 800A to change the expansion plugs, valve stem seals and motor mounts. This Scout has a T39 Automatic Transmission. Engine re-assembly went great, no issues. Installed the engine back in, everything went nice and easy, smooth. I rotated the engine several times during the install process. The engine came down on the mounts fine, leaving about 3/4” between the engine and flywheel housing. I pulled the flywheel housing up to the engine block with a couple of bolts and did not feel any resistance during this process. Now with the T39(just rebuilt) out of park, the engine will not rotate. I mean it is Stuck. Any ideas? Thanks for any assistance.
 
Based on your details, my guess is the torque converter was not fully seated on position. You never use bell housing bolts to bring the two halves together. You always sit behind the trans and wiggle it side to side until things seat into position. There are three distinct clunks as a torque converted gets into position. Done right, you should be able to slide the converter fore/aft about 1/4 inch before it gets bolted to the ring gear. If its hanging up on one of the splines, the converter is locking up against the fluid pump and won't let the ring gear assembly rotate. You'll need to separate the trans an inch or so and see if that releases the pressure. If yes, then its possible you have hurt the fluid pump bushing in the trans by cranking the bell housing bolts to get the two together. You might want to have the shop that rebuilt te trans to take a look. I had a friend with a TH400 in a boat do this and he cracked the pump when installing the out drive (transmission) by using bell housing bolts to bring the two together. Hopefully you maybe have the ring gear on inside out or something simple.
EDIT...IH ring gears are not dished so disregard that.
Anyway, I would release the bell housing bolts and back the trans out and see what's going on.
 
What Dealbreaker said. DO NOT under ANY circumstances attempt to starter crank or even hand crank that engine any further. Damage may have already been done.
 
Thank you Dealbreaker74, and Scoutboy 74 for the info.
I did leave a couple details out in my first post. The T39 is sitting on a jack under the Scout, mounted to the trans case. When I installed the engine, I bolted the TC to the flywheel. I did not hear any distinctive clunks, I do think I felt them when moving the engine and tc towards the bell housing. Today I did loosen everything up like you said and the bell housing opened up about a 1/2” and it would also rotate. So, I got to looking through the service manual for some info on the TC and found a short paragraph on centering the TC. In the manual it indicated the tc mounting bolts needed to be loose and if not, loosen, which I did. With the spark plugs removed, the flywheel needed to be rotated at least two times using a bar and prying off the ring gear teeth. I also did this as well. Afterwards the bell housing bolted up, no resistance at all and the engine rotates just fine. I am hoping that the tranny is not damaged. I did the rebuild on it and it didn’t make any noise (no breaking noise) right up to when the TC would no longer rotate and I stopped immediately when that happened.
 
The way I've always done auto trans to engine unions has been to have the converter fully seated into the transmission first, since that is such a critical interface. After I'm certain that was done properly, then I bring the trans case and engine together and fasten those bolts. Then the converter can be slid forward and aligned with the flex plate mounting holes. Once one or two flex plate bolts are secured, I can then rotate the engine as needed to finish the remaining bolts. Were I in your shoes right now, I'm thinking I'd have some doubt creeping in about whether I had the converter properly engaged with the input pump before I snugged things together. Perhaps you got lucky. Perhaps not. Knowing for sure is better. I fail to see how you could know for sure using the method you did based on your explanation. I might just be dense though.
 
Sounds to me like there is no dense too you at all. Do you feel like the best course of action to take at this point is: Pull the engine and TC, inspect and re-assemble using the steps you described? I’m gonna be honest with you. I do have some doubt as to the TC seating and tranny interface. It just doesn’t seem like it is far enough back. While the engine does now rotate fine the exhaust pipes are not fitting up like they should. There is about 1/4” difference between the manifolds and piping. Not sure it was there before, but I don’t think so.
 
I would definitely get the engine and transmission separated. Ordinarily I would advise leaving the converter in the trans and either dropping the trans as a unit or pulling the engine to gain clearance, but that obviously requires engine rotation to access all of the converter to flex plate bolts. In your case, further engine rotation is probably best avoided. That means leaving the converter attached to the flex plate until the engine and trans are clear of one another. Then the trans input should be carefully inspected for damage. If none found, then the converter could be removed from the flex plate and seated into the transmission as previously described.
 
Thanks again, for the information and also the knowledge that goes with it. It’s settled. I’m going to remove the engine and tc as you described, inspect and go from there. I will get back, and let you know what the trans input looks like, including the tc and the tranny input shaft seal.
 
I hope it goes well for you. Back when I was a teen with zero mechanical experience, my dad and I hired one of his co-workers who was supposedly a good mechanic...to swap a 351 Cleveland and FMX auto trans, both from a '72 Ranchero, into my '57 F-100 pickup. The FMX trans is as I understand, is quite similar to the Borg Warner unit you have. Anyhoo, this guy lets my dad know one day at work that he has the engine and trans in the pickup and that it's ready for us to come and get. When we get there a few days later to take it home, he informs us that at first the engine refused to turn over with the starter, but that he kept trying and trying and finally it all of a sudden began cranking preceded by either a bang or a pop sound. That was wierd! Then he said that he tried putting it in gear but it wouldn't move in either direction. He attributed that to not having enough ATF to bring the level right and perhaps some air trapped in the system. Niether my dad nor I thought too much of it at the time and accepted his explanation as plausible. We fired up the engine and ran it for awhile. It sounded good, so we paid him and towed the truck home. We checked the fluid level, and in fact it was a bit low, so we added fluid to the proper level. The trans still would not engage any gear position. We ran the engine for some time trying to get the trans to go into gear, checking and re-checking the fluid level to no avail. At this point, both my dad and I became very concerned. We decided it was time to drop the trans to see if we could determine what the issue might be. Once the unit was down and out, the issue became instantly apparent even to us greenhorns. The input shaft was completely severed and the broken surfaces were worn partially smooth from all the engine running after the initial breakage. We then dropped the fluid pan and found it to be full of metal chunks and particulate. We asked of a trusted friend with experience what could have caused that and his reply was quite simply not having the converter properly seated when the engine and trans were mated, followed by trying and eventually succeeding in starting the engine. So we scrapped that trans and had the same trusted friend source a good, used C-6 for us, which we successfully installed ourselves. I can remember my dad being very nervous about making sure he got the converter fully seated, but he nailed it.
 
^^^All of that^^^
My boat story ended in misery too. Glad I was a spectator and not the "mechanic" on that one. Hopefully you didn't hurt anything. Keep us in the loop!
 
Well Scoutboy 74 and Dealbreaker 74, your were right. The TC was not seated all the way. I got very lucky as there was no damage to the tranny input to TC shaft or the TC shaft itself or ears. I pulled the engine and followed your directions in seating the TC. During the Install, I rotated the the TC and as you described, I heard the clunks, the last one was loud where the TC shaft bottomed out against the pump housing. Just to be safe, I pulled the TC back and installed it again. I have driven the Scout and she goes forwards and backwards. Thanks again for your help.
 
You must log in or register to reply here.
Back
Top