Transmission won’t rotate. I think this means it’s toast

[Phillytwotank]

Hi y’all,

In process of putting back together this 92 with the used om602. Got excited to try it out and went ahead and mounted the engine with out the trans. Everything fired up and ran perfectly. I’m thinking there’s light at the end of this tunnel so I make a push to wrestle in the trans from underneath.

As soon as I get the trans in I notice that I can no longer rotate the engine.

Pull everything apart again and this is what I find
- engine rotetes just fine with out the trans attached

- the output flange of the trans rotates free, spins all the way through to the smaller splined shaft at the front.

- The larger/outer splined shaft will not rotate. See pics

Can anybody help me confirm what this means please?

[Frank Reiner]

Originally Posted by Phillytwotank

As soon as I get the trans in I notice that I can no longer rotate the engine. Pull everything apart again and this is what I find

- engine rotetes just fine with out the trans attached
- the output flange of the trans rotates free, spins all the way through to the smaller splined shaft at the front.
- The larger/outer splined shaft will not rotate. See pics

Can anybody help me confirm what this means please?

1) The input shaft of the trans should rotate freely, independently of the output shaft.
2) The larger splined shaft is the stator shaft; it does not turn. (Stator = Stationary!!)
3) Install the torque convertor to the trans, making sure that the pump drive lugs have entered the pump.
4) No pics.

[Sugar Bear]

#3 ^^^

The converter probably isn't seated in the front pump. Did the transmission mate flush to the block without bolts? It has to and then the converter should slide forward about 3/16" or so to the flex plate.

Good luck!!!

[t walgamuth]

Some of these swaps have two lengths of bolts and will hit and stop.

[Phillytwotank]

Good info here. Thanks y’all. I guess I’ll mount the TC to the trans first this time then take another stab at it

[tangofox007]

Originally Posted by Phillytwotank

I guess I’ll mount the TC to the trans first this time then take another stab at it

It sometimes takes a bit of wiggling to get the converter seated fully. In my experience, that's best done with the transmission in a vertical position.
In any case, mounting the TC separately to the flex plate is not an approach that I would recommend.

[Sugar Bear]

While rotating the converter and pushing it inward it has two "jump" twice toward the tailshaft. One jump for each of the two splined shafts it couples with.

Good luck!!!

[Zulfiqar]

Originally Posted by Phillytwotank

Good info here. Thanks y’all. I guess I’ll mount the TC to the trans first this time then take another stab at it

Are you trying to mount the transmission to the engine with the torque converter bolted to the flex plate?

If you proceeded to crank down the bellhousing bolts with the torque converter jammed against the flex plate then there is a high chance you have broken the oil pump and that is causing the engine to act as if its locked.

[barry12345]

Never heard of anyone attempting this before. Hopefully no damage.

[BillGrissom]

Sounds the same as the A-904 transmission in my 1969 Dodge Dart, indeed same as my 2002 Chrysler. The larger outer splined shaft which sticks out from the front pump is stationary. A smaller inner shaft is turned by an impeller inside the torque converter (TC). You have to keep rotating and wiggling the TC until it fully engages, which is 2 drops past steps. When correct, the TC bolt-up pads should be 1/2" or more below the bellhousing face (older Chrysler). I didn't know this when a neophyte reinstalling a rebuilt transmission in my 1969 Dart and just kept tightening flange bolts until I stripped a large tapped aluminum hole. Eventually, it settled after driving so could bolt it flush. I don't know what the correct distance is to verify correct seating in my M-B transmission (never touched), but should have a similar spec, and don't force things like this once dumb-kid did.

[Phillytwotank]

Seems to be on the right track now. Pulled everything apart, wiggled the tc onto the safety of the trans first this time. Got it started going back together again. Just got to get the tc bolts off n through the little window which seems like it’s going to be a little tricky

[Sugar Bear]

The transmission bell housing must mate completely flush to the engine block without bolts. If it has to be drawn in flush with bolts the converter is not on the front pump inner splined shaft.

Good luck!!!

[Zulfiqar]

Originally Posted by Phillytwotank

Seems to be on the right track now. Pulled everything apart, wiggled the tc onto the safety of the trans first this time. Got it started going back together again. Just got to get the tc bolts off n through the little window which seems like it’s going to be a little tricky

stuff a tiny magnet into your socket to hold the bolt as you screw them into the converter. Dont forget the medium (blue) threadlocker.

with the converter in place, the transmission should mate up to the engine without issue, and a small gap of about 3/16 inch should exist between the flexplate and the converter. Please make sure the locating dowels are in place otherwise you may have the converter off center to the crank and damage its pilot and have a bad vibration while driving.

[Junkman]

Originally Posted by Zulfiqar

stuff a tiny magnet into your socket to hold the bolt as you screw them into the converter. Dont forget the medium (blue) threadlocker.

You can also put a piece of paper across the socket when you put the bolt head into the socket. Tear off the excess paper and what's left will hold the bolt in the socket. It makes installing bolts easier than having them dropping on the floor.

[Phillytwotank]

I meant “tricky” as in... getting the bolt holes on the TC lined up with the holes in the flywheel and keeping them there whilst push everything together. I’m thinking about using a longer bolt with the head cut off screwed into the TC as a guide to help those holes find each other.