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cant turn engine by hand

5K views 24 replies 8 participants last post by  kahanabob 
#1 ·
4.2l just installed with rebuilt TF999 tranny, engine spun easy by hand on engine stand. Installed flexplate and put some tranny fluid into torque converter and installed.... no issues needed to hold crank bolt to torque flex plate to spec. bolted up torque converter. slid trans on. This took a few attempts but I've done this before and it normally does to get it lined up right.

I did not verify the engine spun freely at this point. :brickwall

Ive never had any trouble before and this is my 10th or better engine install.
dropped engine into jeep installed tcase/skidplate/driveshafts/linkage/etc. just to the point where I'm spinning the engine over to tdc and the damn thing wont spin. Trans is in neutral put tcase in neutral and drive shafts spin free. tcase in 2h or 4h and drive shafts spin with effort so the tranny output shaft is spinning.

I put a torqure wrench on the cranksnout. It doesnt spin with 80ftlbs of torque. Underneath I get on the torque converter bolts and I cant get it to spin. Like I said above the tcase is behaving normally. I'm thinking something is up with the torque converter... This is the original converter I had it rebuilt cause its rare and hard to find. I have confidence in the rebuild.... any ideas? Will call the tranny shop in the morning and see what they think.
 
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#2 ·
The only thing that comes to mind is the torque converter didn't properly engage the front pump when you slid the tranny up to the engine. If it bound on the pump tabs, you could be springing the flex plate as you draw the engine and tranny together.
 
#3 ·
so loosen the tranny bolts/ mounts get a bit of space between the bellhousing and the engine, work the converter back and forth to free it and snug everything back up?
 
#4 ·
That would do it.

It has been years since I have done this, but IIRC, you can remove the lower sheetmetal cover on the bellhousing and unbolt the converter from the flex plate. (without removing the tranny first). Once free of the flexplate, the converter should easily slide deeper (an inch or so) into the front pump, and should also spin freely.

This is a good time to check if the flexplate is binding, and/or the engine will spin without the converter.

BUT, this won't work if everything is locked up, as you have to rotate the engine to access all the converter bolts.
 
#5 ·
You should always seat the torque convertor fully before installing trans to engine. After the transmission is tight to the block THEN you will install your torque convertor bolts. You probably did not get the front pump tabs lined up and when you cranked down on the bellhousing bolts you did one of several things:
Broke the front pump gear (probably), Damaged the torque convertor (probably), damaged the input shaft of the trans (not too likely but could happen), and there is the option of having damaged the turbine in the torque convertor via input shaft being jammed in there (a good chance it happened).

What did we learn here boys and girls?
Don't use shortcuts. The attempt to save a bit of time will probably end up costing you several hundred dollars at least.

Install the torque convertor fully seated IN the transmission. Bolt trans to engine. THEN bolt torque convertor to flex plate. You will probably have to move the torque convertor about 1/4" toward the front of the engine to get it flush with the flex plate (this is completely normal and tells you the torque convertor was fully seated into the front pump). The only time the trans and torque convertor do not go in and come out together is if you have a bolt you cannot get off the flex plate with the trans in place (ie stripped, broken head, cross threaded, etc).
 
#7 ·
Did you install the converter in the trans then bolt it up to the engine. Or the other way around installed the TC to the flex plate then mounted the trans?
 
#8 · (Edited)
I mounted the flex plate to the engine then I bolted the torque converter to the flexplate. We lifted and slid the transmission onto the torque converter. It went in smoothly and the bellhousing slid snugly to the engine. I wasn 't trying to take shortcuts as I said I've done a number of these and this is how I've always done it. I didn't know I was doing it wrong or I would have done it the right way. If there was any binding or gap I wouldn't have used the bolts to pull it together. I've got a ton of money and time invested into this its pretty crummy to assume I did it this way even though I knew better.

The reason I assumed it went this way is its similar to how you would bolt the flywheel and clutch assemby together using a pilot bearing tool to the engine and then bolt the transmission up.... Sorry I'm stupid

Assuming its damaged, what will I see as far as the pump and torque converter. With everything sealed up int the t/c is there anyway to tell?
 
#9 ·
Well you should pull it a part and install the TC in to the trans then bolt it to the engine that is the way it should be done. Right now I think you have not messed up because of the give in the flex plate. You might get lucky to do it the other way but most likely you will blow the pump out because it's in a bind.


Your not stupid just did know better I had to learn the hard way too.
 
#11 ·
So Transmission and Transfer case are down... Engine still wont spin by hand... I know it spun just prior to/while installing the flexplate and converter... Once installed in the jeep I've added the intake and exhaust and the valve cover... I have no idea what else it could be.
 
#12 ·
Mmmm did you bend the flex plate?
 
#13 ·
We had a thread like this about a year ago his turned ou to bea a bearing climed over top on of another dont remember if it was a rod or main. I would check and see if the flex plate had a too long of bolt in it. If it dont the only other thing you can do is pull it down and check bearings.




PS C an you rock the crank and get it to move a little?
 
#15 ·
Yes if you remove the oil pan you can get to the mains and rod bearings.
 
#16 ·
So just an update. Work on the heap has been slow as I tear everything back out. Tranny, TC and Flex plate are out but still no engine rotation. The TC does fit nicely into the bellhousing and spins fine. No grinding or other indications of damage to the Tranny... This weekend I'll get an engine hoist and pull the engine back out and onto a stand... Sigh.

On the upside I jumped on an 89 YJ Sahara I saw for sale. In perfect shape very little rust with a rebuilt engine and tranny. 3500
 
#17 ·
I might be out of place here but did you put the spark plugs in the engine yet?
 
#20 ·
This was a fresh reman engine that I was installing to a rebuilt tranny If you read the whole thread you will get a better idea of where I'm at. At this point I'm updating more for documentation purposes then anything else. Theres no question the engine suffered some sort of problem from my installation of the tranny the question is what and how bad.
 
#21 ·
Willing to bet the tranny install shoved the crank forward hard enough to bind. Can't imagine what else on a fresh engine. If I didn't see anything obvious with the pan and timing cover off, then I would whap the front of the crank a few times with a BFH and see if that frees it up.
 
#22 ·
Well smack my *** and call me stupid. Turns out it was the pulley bolts around the balancer. They were contacting the block and preventing the engine from turning. Just about the dumbest thing I've ever done....

Well at least its fixed and it wasn't the bearings
 
#23 ·
:eek: Well, I gotta admit that I've never seen that one before. That woulda messed me up too. Never heard of it. So I guess you should feel good and party! :2thumbsup:

.
 
#24 ·
That'll do it! Must have been quite overly long for the job to go through everything and hit the block hard enough to prevent turning. I would inspect the damper closely to make sure it didnt get tweaked as it probably had a lot of pressure on it as well. If all is good toss her back together and get her running!
 
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